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- <html>
- <head><title>Thyroid: Therapies, Confusion, and Fraud</title></head>
- <body>
- <h1>
- Thyroid: Therapies, Confusion, and Fraud
- </h1>
-
- I. Respiratory-metabolic defect II. 50 years of commercially motivated fraud III. Tests and the "free hormone
- hypothesis" IV. Events in the tissues V. Therapies VI. Diagnosis
-
- <strong>I. Respiratory defect</strong>
-
- Broda Barnes, more than 60 years ago, summed up the major effects of hypothyroidism on health very neatly when
- he pointed out that if hypothyroid people don't die young from infectious diseases, such as tuberculosis, they
- die a little later from cancer or heart disease. He did his PhD research at the University of Chicago, just a
- few years after Otto Warburg, in Germany, had demonstrated the role of a "respiratory defect" in cancer. At the
- time Barnes was doing his research, hypothyroidism was diagnosed on the basis of a low basal metabolic rate,
- meaning that only a small amount of oxygen was needed to sustain life. This deficiency of oxygen consumption
- involved the same enzyme system that Warburg was studying in cancer cells. Barnes experimented on rabbits, and
- found that when their thyroid glands were removed, they developed atherosclerosis, just as hypothyroid people
- did. By the mid-1930s, it was generally known that hypothyroidism causes the cholesterol level in the blood to
- increase; hypercholesterolemia was a diagnostic sign of hypothyroidism. Administering a thyroid supplement,
- blood cholesterol came down to normal exactly as the basal metabolic rate came up to the normal rate. The
- biology of atherosclerotic heart disease was basically solved before the second world war. Many other diseases
- are now known to be caused by respiratory defects. Inflammation, stress, immunodeficiency, autoimmunity,
- developmental and degenerative diseases, and aging, all involve significantly abnormal oxidative processes. Just
- brief oxygen deprivation triggers processes that lead to lipid peroxidation, producing a chain of other
- oxidative reactions when oxygen is restored. The only effective way to stop lipid peroxidation is to restore
- normal respiration. Now that dozens of diseases are known to involve defective respiration, the idea of
- thyroid's extremely broad range of actions is becoming easier to accept.
-
- <strong>II. 50 years of fraud</strong>
-
- Until the second world war, hypothyroidism was diagnosed on the basis of BMR (basal metabolic rate) and a large
- group of signs and symptoms. In the late 1940s, promotion of the (biologically inappropriate) PBI (protein-bound
- iodine) blood test in the U.S. led to the concept that only 5% of the population were hypothyroid, and that the
- 40% identified by "obsolete" methods were either normal, or suffered from other problems such as sloth and
- gluttony, or "genetic susceptibility" to disease. During the same period, thyroxine became available, and in
- healthy young men it acted "like the thyroid hormone." Older practitioners recognized that it was not
- metabolically the same as the traditional thyroid substance, especially for women and seriously hypothyroid
- patients, but marketing, and its influence on medical education, led to the false idea that the standard Armour
- thyroid USP wasn't properly standardized, and that certain thyroxine products were; despite the fact that both
- of these were shown to be false. By the 1960s, the PBI test was proven to be irrelevant to the diagnosis of
- hypothyroidism, but the doctrine of 5% hypothyroidism in the populaton became the basis for establishing the
- norms for biologically meaningful tests when they were introduced. Meanwhile, the practice of measuring serum
- iodine, and equating it with "thyroxine the thyroid hormone," led to the practice of examining only the iodine
- content of the putative glandular material that was offered for sale as thyroid USP. This led to the
- substitution of materials such as iodinated casein for desiccated thyroid in the products sold as thyroid USP.
- The US FDA refused to take action, because they held that a material's iodine content was enough to identify it
- as "thyroid USP." In this culture of misunderstanding and misrepresentation, the mistaken idea of
- hypothyroidism's low incidence in the population led to the acceptance of dangerously high TSH (thyroid
- stimulating hormone) activity as "normal." Just as excessive FSH (follicle stimulating hormone) has been shown
- to have a role in ovarian cancer, excessive stimulation by TSH produces disorganization in the thyroid gland.
-
- <strong>III. Tests & the "free hormone hypothesis"</strong>
-
- After radioactive iodine became available, many physicians would administer a dose, and then scan the body with
- a Geiger counter, to see if it was being concentrated in the thyroid gland. If a person had been eating
- iodine-rich food (and iodine was used in bread as a preservative/dough condition, and was present in other foods
- as an accidental contaminant), they would already be over saturated with iodine, and the gland would fail to
- concentrate the iodine. The test can find some types of metastatic thyroid cancer, but the test generally wasn't
- used for that purpose. Another expensive and entertaining test has been the thyrotropin release hormone (TRH)
- test, to see if the pituitary responds to it by increasing TSH production. A recent study concluded that "TRH
- test gives many misleading results and has an elevated cost/benefit ratio as compared with the characteristic
- combination of low thyroxinemia and non-elevated TSH." (Bakiri, Ann. Endocr (Paris) 1999), but the technological
- drama, cost, and danger (Dokmetas, et al., J Endocrinol Invest 1999 Oct; 22(9): 698-700) of this test is going
- to make it stay popular for a long time. If the special value of the test is to diagnose a pituitary
- abnormality, it seems intuitively obvious that overstimulating the pituitary might not be a good idea (e.g., it
- could cause a tumor to grow). Everything else being equal, as they say, looking at the amount of thyroxine and
- TSH in the blood can be informative. The problem is that it's just a matter of faith that "everything else" is
- going to be equal. The exceptions to the "rule" regarding normal ranges for thyroxine and TSH have formed the
- basis for some theories about "the genetics of thyroid resistance," but others have pointed out that, when a few
- other things are taken into account, abnormal numbers for T4, T3, TSH, can be variously explained. The actual
- quantity of T3, the active thyroid hormone, in the blood can be measured with reasonable accuracy (using
- radioimmunoassay, RIA), and this single test corresponds better to the metabolic rate and other meaningful
- biological responses than other standard tests do. But still, this is only a statistical correspondence, and it
- doesn't indicate that any particular number is right for a particular individual. Sometimes, a test called the
- RT3U, or resin T3 uptake, is used, along with a measurement of thyroxine. A certain amount of radioactive T3 is
- added to a sample of serum, and then an adsorbent material is exposed to the mixture of serum and radioactive
- T3. The amount of radioactivity that sticks to the resin is called the T3 uptake. The lab report then gives a
- number called T7, or free thyroxine index. The closer this procedure is examined, the sillier it looks, and it
- looks pretty silly on its face.. The idea that the added radioactive T3 that sticks to a piece of resin will
- correspond to "free thyroxine," is in itself odd, but the really interesting question is, what do they mean by
- "free thyroxine"? Thyroxine is a fairly hydrophobic (insoluble in water) substance, that will associate with
- proteins, cells, and lipoproteins in the blood, rather than dissolving in the water. Although the Merck Index
- describes it as "insoluble in water," it does contain some polar groups that, in the right (industrial or
- laboratory) conditions, can make it slightly water soluble. This makes it a little different from progesterone,
- which is simply and thoroughly insoluble in water, though the term "free hormone" is often applied to
- progesterone, as it is to thyroid. In the case of progesterone, the term "free progesterone" can be traced to
- experiments in which serum containing progesterone (bound to proteins) is separated by a (dialysis) membrane
- from a solution of similar proteins which contain no progesterone. Progesterone "dissolves in" the substance of
- the membrane, and the serum proteins, which also tend to associate with the membrane, are so large that they
- don't pass through it. On the other side, proteins coming in contact with the membrane pick up some
- progesterone. The progesterone that passes through is called "free progesterone," but from that experiment,
- which gives no information on the nature of the interactions between progesterone and the dialysis membrane, or
- about its interactions with the proteins, or the proteins' interactions with the membrane, nothing is revealed
- about the reasons for the transmission or exchange of a certain amount of progesterone. Nevertheless, that type
- of experiment is used to interpret what happens in the body, where there is nothing that corresponds to the
- experimental set-up, except that some progesterone is associated with some protein. The idea that the "free
- hormone" is the active form has been tested in a few situations, and in the case of the thyroid hormone, it is
- clearly not true for the brain, and some other organs. The protein-bound hormone is, in these cases, the active
- form; the associations between the "free hormone" and the biological processes and diseases will be completely
- false, if they are ignoring the active forms of the hormone in favor of the less active forms. The conclusions
- will be false, as they are when T4 is measured, and T3 ignored. Thyroid-dependent processes will appear to be
- independent of the level of thyroid hormone; hypothyroidism could be caller hyperthyroidism. Although
- progesterone is more fat soluble than cortisol and the thyroid hormones, the behavior of progesterone in the
- blood illustrates some of the problems that have to be considered for interpreting thyroid physiology. When red
- cells are broken up, they are found to contain progesterone at about twice the concentration of the serum. In
- the serum, 40 to 80% of the progesterone is probably carried on albumin. (Albumin easily delivers its
- progesterone load into tissues.) Progesterone, like cholesterol, can be carried on/in the lipoproteins, in
- moderate quantities. This leaves a very small fraction to be bound to the "steroid binding globulin." Anyone who
- has tried to dissolve progesterone in various solvents and mixtures knows that it takes just a tiny amount of
- water in a solvent to make progesterone precipitate from solution as crystals; its solubility in water is
- essentially zero. "Free" progesterone would seem to mean progesterone not attached to proteins or dissolved in
- red blood cells or lipoproteins, and this would be zero. The tests that purport to measure free progesterone are
- measuring something, but not the progesterone in the watery fraction of the serum. The thyroid hormones
- associate with three types of simple proteins in the serum: Transthyretin (prealbumin), thyroid binding
- globulin, and albumin. A very significant amount is also associated with various serum lipoproteins, including
- HDL, LDL, and VLDL (very low density lipoproteins). A very large portion of the thyroid in the blood is
- associated with the red blood cells. When red cells were incubated in a medium containing serum albumin, with
- the cells at roughly the concentration found in the blood, they retained T3 at a concentration 13.5 times higher
- than that of the medium. In a larger amount of medium, their concentration of T3 was 50 times higher than the
- medium's. When laboratories measure the hormones in the serum only, they have already thrown out about 95% of
- the thyroid hormone that the blood contained. The T3 was found to be strongly associated with the cells'
- cytoplasmic proteins, but to move rapidly between the proteins inside the cells and other proteins outside the
- cells. When people speak of hormones travelling "on" the red blood cells, rather than "in" them, it is a
- concession to the doctrine of the impenetrable membrane barrier. Much more T3 bound to albumin is taken up by
- the liver than the small amount identified in vitro as free T3 (Terasaki, et al., 1987). The specific binding of
- T3 to albumin alters the protein's electrical properties, changing the way the albumin interacts with cells and
- other proteins. (Albumin becomes electrically more positive when it binds the hormone; this would make the
- albumin enter cells more easily. Giving up its T3 to the cell, it would become more negative, making it tend to
- leave the cell.) This active role of albumin in helping cells take up T3 might account for its increased uptake
- by the red cells when there were fewer cells in proportion to the albumin medium. This could also account for
- the favorable prognosis associated with higher levels of serum albumin in various sicknesses. When T3 is
- attached chemically (covalently, permanently) to the outside of red blood cells, apparently preventing its entry
- into other cells, the presence of these red cells produces reactions in other cells that are the same as some of
- those produced by the supposedly "free hormone." If T3 attached to whole cells can exert its hormonal action,
- why should we think of the hormone bound to proteins as being unable to affect cells? The idea of measuring the
- "free hormone" is that it supposedly represents the biologically active hormone, but in fact it is easier to
- measure the biological effects than it is to measure this hypothetical entity. Who cares how many angels might
- be dancing on the head of a pin, if the pin is effective in keeping your shirt closed?
-
- <strong>IV. Events in the tissues</strong>
-
- Besides the effects of commercial deception, confusion about thyroid has resulted from some biological clich"s.
- The idea of a "barrier membrane" around cells is an assumption that has affected most people studying cell
- physiology, and its effects can be seen in nearly all of the thousands of publications on the functions of
- thyroid hormones. According to this idea, people have described a cell as resembling a droplet of a watery
- solution, enclosed in an oily bag which separates the internal solution from the external watery solution. The
- clich" is sustained only by neglecting the fact that proteins have a great affinity for fats, and fats for
- proteins; even soluble proteins, such as serum albumin, often have interiors that are extremely fat-loving.
- Since the structural proteins that make up the framework of a cell aren't "dissolved in water" (they used to be
- called "the insoluble proteins"), the lipophilic phase isn't limited to an ultramicroscopically thin surface,
- but actually constitutes the bulk of the cell. Molecular geneticists like to trace their science from a 1944
- experiment that was done by Avery., et al. Avery's group knew about an earlier experiment, that had demonstrated
- that when dead bacteria were added to living bacteria, the traits of the dead bacteria appeared in the living
- bacteria. Avery's group extracted DNA from the dead bacteria, and showed that adding it to living bacteria
- transferred the traits of the dead organisms to the living. In the 1930s and 1940s, the movement of huge
- molecules such as proteins and nucleic acids into cells and out of cells wasn't a big deal; people observed it
- happening, and wrote about it. But in the 1940s the idea of the barrier membrane began gaining strength, and by
- the 1960s nothing was able to get into cells without authorization. At present, I doubt that any molecular
- geneticist would dream of doing a gene transplant without a "vector" to carry it across the membrane barrier.
- Since big molecules are supposed to be excluded from cells, it's only the "free hormone" which can find its
- specific port of entry into the cell, where another clich" says it must travel into the nucleus, to react with a
- specific site to activate the specific genes through which its effects will be expressed. I don't know of any
- hormone that acts that way. Thyroid, progesterone, and estrogen have many immediate effects that change the
- cell's functions long before genes could be activated. Transthyretin, carrying the thyroid hormone, enters the
- cell's mitochondria and nucleus (Azimova, et al., 1984, 1985). In the nucleus, it immediately causes generalized
- changes in the structure of chromosomes, as if preparing the cell for major adaptive changes. Respiratory
- activation is immediate in the mitochondria, but as respiration is stimulated, everything in the cell responds,
- including the genes that support respiratory metabolism. When the membrane people have to talk about the entry
- of large molecules into cells, they use terms such as "endocytosis" and "translocases," that incorporate the
- assumption of the barrier. But people who actually investigate the problem generally find that "diffusion,"
- "codiffusion," and absorption describe the situation adequately (e.g., B.A. Luxon, 1997; McLeese and Eales,
- 1996). "Active transport" and "membrane pumps" are ideas that seem necessary to people who haven't studied the
- complex forces that operate at phase boundaries, such as the boundary between a cell and its environment.
-
- <strong>V. Therapy</strong>
-
- Years ago it was reported that Armour thyroid, U.S.P., released T3 and T4, when digested, in a ratio of 1:3, and
- that people who used it had much higher ratios of T3 to T4 in their serum, than people who took only thyroxine.
- The argument was made that thyroxine was superior to thyroid U.S.P., without explaining the significance of the
- fact that healthy people who weren't taking any thyroid supplement had higher T3:T4 ratios than the people who
- took thyroxine, or that our own thyroid gland releases a high ratio of T3 to T4. The fact that the T3 is being
- used faster than T4, removing it from the blood more quickly than it enters from the thyroid gland itself,
- hasn't been discussed in the journals, possibly because it would support the view that a natural glandular
- balance was more appropriate to supplement than pure thyroxine. The serum's high ratio of T4 to T3 is a
- pitifully poor argument to justify the use of thyroxine instead of a product that resembles the proportion of
- these substances secreted by a healthy thyroid gland, or maintained inside cells. About 30 years ago, when many
- people still thought of thyroxine as "the thryoid hormone," someone was making the argument that "the thyroid
- hormone" must work exclusively as an activator of genes, since most of the organ slices he tested didn't
- increase their oxygen consumption when it was added. In fact, the addition of thyroxine to brain slices
- suppressed their respiration by 6% during the experiment. Since most T3 is produced from T4 in the liver, not in
- the brain, I think that experiment had great significance, despite the ignorant interpretation of the author. An
- excess of thyroxine, in a tissue that doesn't convert it rapidly to T3, has an antithyroid action. (See Goumaz,
- et al, 1987.) This happens in many women who are given thyroxine; as their dose is increased, their symptoms get
- worse. The brain concentrates T3 from the serum, and may have a concentration 6 times higher than the serum
- (Goumaz, et al., 1987), and it can achieve a higher concentration of T3 than T4. It takes up and concentrates
- T3, while tending to expel T4. Reverse T3 (rT3) doesn't have much ability to enter the brain, but increased T4
- can cause it to be produced in the brain. These observations suggest to me that the blood's T3:T4 ratio would be
- very "brain favorable" if it approached more closely to the ratio formed in the thyroid gland, and secreted into
- the blood. Although most synthetic combination thyroid products now use a ratio of four T4 to one T3, many
- people feel that their memory and thinking are clearer when they take a ratio of about three to one. More active
- metabolism probably keeps the blood ratio of T3 to T4 relatively high, with the liver consuming T4 at about the
- same rate that T3 is used. Since T3 has a short half life, it should be taken frequently. If the liver isn't
- producing a noticeable amount of T3, it is usually helpful to take a few micorgrams per hour. Since it restores
- respiration and metabolic efficiency very quickly, it isn't usually necessary to take it every hour or two, but
- until normal temperature and pulse have been achieved and stabilized, sometimes it's necessary to take it four
- or more times during the day. T4 acts by being changed to T3, so it tends to accumulate in the body, and on a
- given dose, usually reaches a steady concentration after about two weeks. An effective way to use supplements is
- to take a combination T4-T3 dose, e.g., 40 mcg of T4 and 10 mcg of T3 once a day, and to use a few mcg of T3 at
- other times in the day. Keeping a 14-day chart of pulse rate and temperature allows you to see whether the dose
- is producing the desired response. If the figures aren't increasing at all after a few days, the dose can be
- increased, until a gradual daily increment can be seen, moving toward the goal at the rate of about 1/14 per day
-
- <strong>VI. Diagnosis</strong>
-
- In the absence of commercial techniques that reflect thyroid physiology realistically, there is no valid
- alternative to diagnosis based on the known physiological indicators of hypothyroidism and hyperthyroidism. The
- failure to treat sick people because of one or another blood test that indicates "normal thyroid function," or
- the destruction of patients' healthy thyroid glands because one of the tests indicates hyperthyroidism, isn't
- acceptable just because it's the professional standard, and is enforced by benighted state licensing boards.
- Toward the end of the twentieth century, there has been considerable discussion of "evidence-based medicine."
- Good judgment requires good information, but there are forces that would over-rule individual judgment as to
- whether published information is applicable to certain patients. In an atmosphere that sanctions prescribing
- estrogen or insulin without evidence of an estrogen deficiency or insulin deficiency, but that penalizes
- practitioners who prescribe thyroid to correct symptoms, the published "evidence" is necessarily heavily biased.
- In this context, "meta-analysis" becomes a tool of authoritarianism, replacing the use of judgment with the
- improper use of statistical analysis. Unless someone can demonstrate the scientific invalidity of the methods
- used to diagnose hypothyroidism up to 1945, then they constitute the best present evidence for evaluating
- hypothyroidism, because all of the blood tests that have been used since 1950 have been.shown to be, at best,
- very crude and conceptually inappropriate methods. Thomas H. McGavack's 1951 book, The Thyroid, was
- representative of the earlier approach to the study of thyroid physiology. Familiarity with the different
- effects of abnormal thyroid function under different conditions, at different ages, and the effects of gender,
- were standard parts of medical education that had disappeared by the end of the century. Arthritis,
- irregularities of growth, wasting, obesity, a variety of abnormalities of the hair and skin, carotenemia,
- amenorrhea, tendency to miscarry, infertility in males and females, insomnia or somnolence, emphysema, various
- heart diseases, psychosis, dementia, poor memory, anxiety, cold extremities, anemia, and many other problems
- were known reasons to suspect hypothyroidism. If the physician didn't have a device for measuring oxygen
- consumption, estimated calorie intake could provide supporting evidence. The Achilles' tendon reflex was another
- simple objective measurement with a very strong correlation to the basal metabolic rate. Skin electrical
- resistance, or whole body impedance wasn't widely accepted, though it had considerable scientific validity. A
- therapeutic trial was the final test of the validity of the diagnosis: If the patient's symptoms disappeared as
- his temperature and pulse rate and food intake were normalized, the diagnostic hypothesis was confirmed. It was
- common to begin therapy with one or two grains of thyroid, and to adjust the dose according to the patient's
- response. Whatever objective indicator was used, whether it was basal metabolic rate, or serum cholesterol. or
- core temperature, or reflex relaxation rate, a simple chart would graphically indicate the rate of recovery
- toward normal health.
-
- <strong><h3>REFERENCES</h3></strong>
-
- McGavack, Thomas Hodge.: The thyroid,: St. Louis, Mosby, 1951. 646 p. ill.Several chapters contributed by
- various authors.Call Numbers WK200 M145t 1951 (Rare Book). Endocrinology 1979 Sep; 105(3): 605-12.
- Carrier-mediated transport of thyroid hormones through the rat blood-brain barrier: primary role of
- albumin-bound hormone. Pardridge WM. Endocrinology 1987 Apr;120(4):1590-6. Brain cortex reverse triiodothyronine
- (rT3) and triiodothyronine concentrations under steady state infusions of thyroxine and rT3. Goumaz MO, Kaiser
- CA, Burger A.G. J Clin Invest 1984 Sep;74(3):745-52. Tracer kinetic model of blood-brain barrier transport of
- plasma protein-bound ligands. Empiric testing of the free hormone hypothesis. Pardridge WM, Landaw EM. Previous
- studies have shown that the fraction of hormone or drug that is plasma protein bound is readily available for
- transport through the brain endothelial wall, i.e., the blood-brain barrier (BBB). To test whether these
- observations are reconcilable with the free-hormone hypothesis, a tracer-kinetic model is used Endocrinology
- 113(1), 391-8, 1983, Stimulation of sugar transport in cultured heart cells by triiodothyronine (T2) covalently
- bound to red blood cells and by T3 in the presence of serum, Dickstein Y, Schwartz H, Gross J, Gordon A.
- Endocrinology 1987 Sep; 121(3): 1185-91. Stereospecificity of triiodothyronine transport into brain, liver, and
- salivary gland: role of carrier- and plasma protein-mediated transport. Terasaki T, Pardridge WM. J.
- Neurophysiol 1994 Jul;72(1):380-91. Film autoradiography identifies unique features of [125I]3,3'5'-(reverse)
- triiodothyronine transport from blood to brain. Cheng LY, Outterbridge LV, Covatta ND, Martens DA, Gordon JT,
- Dratman MB Brain Res 1991 Jul 19;554(1-2):229-36. Transport of iodothyronines from bloodstream to brain:
- contributions by blood:brain and choroid plexus:cerebrospinal fluid barriers. Dratman MB, Crutchfield FL,
- Schoenhoff MB.. Mech Ageing Dev 1990 Mar 15;52(2-3):141-7. Blood-brain transport of triiodothyronine is reduced
- in aged rats. Mooradian AD Geriatrics Section, Tucson VA Medical Center, AZ. Endocrinology 1987
- Sep;121(3):1185-91. Stereospecificity of triiodothyronine transport into brain, liver, and salivary gland: role
- of carrier- and plasma protein-mediated transport. Terasaki T, Pardridge WM. J Clin Invest 1984
- Sep;74(3):745-52. Tracer kinetic model of blood-brain barrier transport of plasma protein-bound ligands. Empiric
- testing of the free hormone hypothesis. Pardridge WM, Landaw EM. Endocrinology 1980 Dec;107(6):1705-10.
- Transport of thyroid and steroid hormones through the blood-brain barrier of the newborn rabbit: primary role of
- protein-bound hormone. Pardridge WM, Mietus LJ. Endocrinology 1979 Sep; 105(3): 605-12. Carrier-mediated
- transport of thyroid hormones through the rat blood-brain barrier: primary role of albumin-bound hormone.
- Pardridge WM. Endocrinology 1975 Jun;96(6):1357-65. Triiodothyronine binding in rat anterior pituitary,
- posterior pituitary, median eminence and brain. Gordon A, Spira O. Endocr Rev 1989 Aug;10(3):232-74. The free
- hormone hypothesis: a physiologically based mathematical model. Mendel CM. Biochim Biophys Acta 1991 Mar
- 4;1073(2):275-84. Transport of steroid hormones facilitated by serum proteins. Watanabe S, Tani T, Watanabe S,
- Seno M Kanagawa. D Novitzky, H Fontanet, M Snyder, N Coblio, D Smith, V Parsonnet, Impact of triiodothyronine on
- the survival of high-risk patients undergoing open heart surgery, Cardiology, 1996, Vol 87, Iss 6, pp 509-515.
- Biochim Biophys Acta 1997. Jan 16;1318(1-2):173-83 Regulation of the energy coupling in mitochondria by some
- steroid and thyroid hormones. Starkov AA, Simonyan RA, Dedukhova VI, Mansurova SE, Palamarchuk LA, Skulachev VP
- Thyroid 1996 Oct;6(5):531-6. Novel actions of thyroid hormone: the role of triiodothyronine in cardiac
- transplantation. Novitzky D. Rev Med Chil 1996 Oct;124(10):1248-50. [Severe cardiac failure as complication of
- primary hypothyroidism]. Novik V, Cardenas IE, Gonzalez R, Pena M, Lopez Moreno JM. Cardiology 1996
- Nov-Dec;87(6):509-15. Impact of triiodothyronine on the survival of high-risk patients undergoing open heart
- surgery. Novitzky D, Fontanet H, Snyder M, Coblio N, Smith D, Parsonnet V Curr Opin Cardiol 1996
- Nov;11(6):603-9. The use of thyroid hormone in cardiac surgery. Dyke C N Koibuchi, S Matsuzaki, K Ichimura, H
- Ohtake, S Yamaoka. Ontogenic changes in the expression of cytochrome c oxidase subunit I gene in the cerebellar
- cortex of the perinatal hypothyroid rat. Endocrinology, 1996, Vol 137, Iss 11, pp 5096-5108. Biokhimiia 1984
- Aug;49(8):1350-6. [The nature of thyroid hormone receptors. Translocation of thyroid hormones through plasma
- membranes]. [Article in Russian] Azimova ShS, Umarova GD, Petrova OS, Tukhtaev KR, Abdukarimov A. The in vivo
- translocation of thyroxine-binding blood serum prealbumin (TBPA) was studied. It was found that the TBPA-hormone
- complex penetrates-through the plasma membrane into the cytoplasm of target cells. Electron microscopic
- autoradiography revealed that blood serum TBPA is localized in ribosomes of target cells as well as in
- mitochondria, lipid droplets and Golgi complex. Negligible amounts of the translocated TBPA is localized in
- lysosomes of the cells insensitive to thyroid hormones (spleen macrophages). Study of T4- and T3-binding
- proteins from rat liver cytoplasm demonstrated that one of them has the antigenic determinants common with those
- of TBPA. It was shown autoimmunoradiographically that the structure of TBPA is not altered during its
- translocation. Am J Physiol 1997 Sep;273(3 Pt 1):C859-67. Cytoplasmic codiffusion of fatty acids is not specific
- for fatty acid binding protein. Luxon BA, Milliano MT [The nature of thyroid hormone receptors. Intracellular
- functions of thyroxine-binding prealbumin] Azimova ShS; Normatov K; Umarova GD; Kalontarov AI; Makhmudova AA,
- Biokhimiia 1985 Nov;50(11):1926-32. The effect of tyroxin-binding prealbumin (TBPA) of blood serum on the
- template activity of chromatin was studied. It was found that the values of binding constants of TBPA for T3 and
- T4 are 2 X 10(-11) M and 5 X 10(-10) M, respectively. The receptors isolated from 0.4 M KCl extract of chromatin
- and mitochondria as well as hormone-bound TBPA cause similar effects on the template activity of chromatin.
- Based on experimental results and the previously published comparative data on the structure of TBPA, nuclear,
- cytoplasmic and mitochondrial receptors of thyroid hormones as well as on translocation across the plasma
- membrane and intracellular transport of TBPA, a conclusion was drawn, which suggested that TBPA is the "core" of
- the true thyroid hormone receptor. It was shown that T3-bound TBPA caused histone H1-dependent conformational
- changes in chromatin. Based on the studies with the interaction of the TBPA-T3 complex with spin-labeled
- chromatin, a scheme of functioning of the thyroid hormone nuclear receptor was proposed. [The nature of thyroid
- hormone receptors. Thyroxine- and triiodothyronine-binding proteins of mitochondria] Azimova ShS; Umarova GD;
- Petrova OS; Tukhtaev KR; Abdukarimov A. Biokhimiia 1984 Sep;49(9):1478-85. T4- and T3-binding proteins of rat
- liver were studied. It was found that the external mitochondrial membranes and matrix contain a protein whose
- electrophoretic mobility is similar to that of thyroxine-binding blood serum prealbumin (TBPA) and which binds
- either T4 or T3. This protein is precipitated by monospecific antibodies against TBPA. The internal
- mitochondrial membrane has two proteins able to bind thyroid hormones, one of which is localized in the cathode
- part of the gel and binds only T3, while the second one capable of binding T4 rather than T3 and possessing the
- electrophoretic mobility similar to that of TBPA. Radioimmunoprecipitation with monospecific antibodies against
- TBPA revealed that this protein also the antigenic determinants common with those of TBPA. The in vivo
- translocation of 125I-TBPA into submitochondrial fractions was studied. The analysis of densitograms of
- submitochondrial protein fraction showed that both TBPA and hormones are localized in the same protein
- fractions. Electron microscopic autoradiography demonstrated that 125I-TBPA enters the cytoplasm through the
- external membrane and is localized on the internal mitochondrial membrane and matrix. [The nature of thyroid
- hormone receptors. Translocation of thyroid hormones through plasma membranes]. Azimova ShS; Umarova GD; Petrova
- OS; Tukhtaev KR; Abdukarimov A. Biokhimiia 1984 Aug;49(8):1350-6.. The in vivo translocation of thyroxine-
- binding blood serum prealbumin (TBPA) was studied. It was found that the TBPA-hormone complex penetrates-through
- the plasma membrane into the cytoplasm of target cells. Electron microscopic autoradiography revealed that blood
- serum TBPA is localized in ribosomes of target cells as well as in mitochondria, lipid droplets and Golgi
- complex. Negligible amounts of the translocated TBPA is localized in lysosomes of the cells insensitive to
- thyroid hormones (spleen macrophages). Study of T4- and T3-binding proteins from rat liver cytoplasm
- demonstrated that one of them has the antigenic determinants common with those of TBPA. It was shown
- autoimmunoradiographically that the structure of TBPA is not altered during its translocation. Endocrinology
- 1987 Apr;120(4):1590-6 Brain cortex reverse triiodothyronine (rT3) and triiodothyronine concentrations under
- steady state infusions of thyroxine and rT3. Goumaz MO, Kaiser CA, Burger AG. Gen Comp Endocrinol 1996
- Aug;103(2):200-8 Characteristics of the uptake of 3,5,3'-triiodo-L-thyronine and L-thyroxine into red blood
- cells of rainbow trout (Oncorhynchus mykiss). McLeese JM, Eales JG. Prog Neuropsychopharmacol Biol Psychiatry
- 1998 Feb;22(2):293-310. Increase in red blood cell triiodothyronine uptake in untreated unipolar major depressed
- patients compared to healthy volunteers. Moreau X, Azorin JM, Maurel M, Jeanningros R. Prog Neuropsychopharmacol
- Biol Psychiatry 1998 Feb;22(2):293-310. Increase in red blood cell triiodothyronine uptake in untreated unipolar
- major depressed patients compared to healthy volunteers. Moreau X, Azorin JM, Maurel M, Jeanningros R. Biochem J
- 1982 Oct 15;208(1):27-34. Evidence that the uptake of tri-iodo-L-thyronine by human erythrocytes is
- carrier-mediated but not energy-dependent. Docter R, Krenning EP, Bos G, Fekkes DF, Hennemann G. J Clin
- Endocrinol Metab 1990 Dec;71(6):1589-95. Transport of thyroid hormones by human erythrocytes: kinetic
- characterization in adults and newborns. Osty J, Valensi P, Samson M, Francon J, Blondeau JP. J Endocrinol
- Invest 1999 Apr;22(4):257-61. Kinetics of red blood cell T3 uptake in hypothyroidism with or without hormonal
- replacement, in the rat. Moreau X, Lejeune PJ, Jeanningros R.
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