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Hyperthyroidism Insulin Resistance

Thyroid Disorders And Diabetes

Thyroid Disorders And Diabetes

Thyroid disorders are very common in the general U.S. population, affecting up to 27 million Americans, although half that number remains undiagnosed. It is second only to diabetes as the most common condition to affect the endocrine system — a group of glands that secrete hormones that help regulate growth, reproduction, and nutrient use by cells. As a result, it is common for an individual to be affected by both thyroid disease and diabetes. Since the thyroid gland plays a central role in the regulation of metabolism, abnormal thyroid function can have a major impact on the control of diabetes. In addition, untreated thyroid disorder can increase the risk of certain diabetic complications and can aggravate many diabetes symptoms. Luckily, abnormal thyroid function can easily be diagnosed by simple blood tests, and effective treatment is available. For all of these reasons, periodic screening for thyroid disorder should be considered in all people with diabetes. What is the thyroid? The thyroid is a butterfly-shaped gland located in the neck, just below the Adam’s apple and above the collarbone. It produces two hormones, thyroxine (T4) and triiodothyronine (T3), which enter the bloodstream and affect the metabolism of the heart, liver, muscles, and other organs. The thyroid gland operates as part of a feedback mechanism involving the hypothalamus, an area of the brain, and the pituitary gland, which is located within the brain. First, the hypothalamus sends a signal to the pituitary through a hormone called TRH (thyrotropin-releasing hormone). When the pituitary gland receives this signal, it releases TSH (thyroid-stimulating hormone) to the thyroid gland. Upon receiving TSH, the thyroid responds by producing and releasing the two thyroid hormones (T3 and T4). The Continue reading >>

Insulin Resistance In Hyperthyroidism: The Role Of Il6 And Tnf

Insulin Resistance In Hyperthyroidism: The Role Of Il6 And Tnf

Insulin resistance in hyperthyroidism: the role of IL6 and TNF 1Hellenic National Center for Research, Prevention and Treatment of Diabetes Mellitus and its Complications (H.N.D.C), GR-10675 Athens, Greece 22nd Department of Internal Medicine, Athens University Medical School, Research Institute and Diabetes Center, Attikon University Hospital, 1 Rimini Street, GR-12462 Haidari, Greece (Correspondence should be addressed to G Dimitriadis; Email: gdimi{at}ath.forthnet.gr) Objective Although insulin resistance is a common finding in hyperthyroidism, the implicated mechanisms are obscure. The aim of this study was to investigate whether interleukin 6 (IL6) and tumour necrosis factor (TNF) are related to the development of insulin resistance in hyperthyroidism of nonautoimmune origin. Design and methods A meal was given to ten hyperthyroid (HR) and ten euthyroid (EU) women. Plasma samples were taken for 360 min from the radial artery for measurements of glucose, insulin, and nonesterified fatty acids (NEFA). IL6 and TNF were measured preprandially from the superficial epigastric vein and from the radial artery. Results i) In HR versus EU: (a) arterial glucose was similar (AUC0360 208757 vs 201043 mMmin), but insulin was increased (AUC0360 17 2672447 vs 10 331666 U/mlmin, P=0.01), (b) homeostasis model assessment (HOMA) was increased (2.30.4 vs 10.1 kg/m2, P=0.007), (c) arterial NEFA were increased (AUC0360 13618 vs 897 mmol/lmin, P=0.03), (d) arterial IL6 (20.3 vs 0.90.1 pg/ml, P=0.0009) and TNF (4.20.8 vs 1.50.2 pg/ml, P=0.003) were increased, and (e) IL6 production from the subcutaneous adipose tissue (AT) was increased (186 vs 51 pg/min per 100 ml tissue, P=0.04). ii) (a) Subcutaneous venous IL6 was positively associated with HOMA (-coefficient=1.70.7, P=0.049) and (b) Continue reading >>

Why Can Insulin Resistance Be A Natural Consequence Of Thyroid Dysfunction?

Why Can Insulin Resistance Be A Natural Consequence Of Thyroid Dysfunction?

Journal of Thyroid Research Volume 2011 (2011), Article ID 152850, 9 pages Department of Endocrinology, Dr. César Milstein Hospital, La Rioja 951, C1221ACI, Buenos Aires, Argentina Academic Editor: Masanobu Yamada Copyright © 2011 Gabriela Brenta. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Abstract Evidence for a relationship between T4 and T3 and glucose metabolism appeared over 100 years ago when the influence of thyroid hormone excess in the deterioration of glucose metabolism was first noticed. Since then, it has been known that hyperthyroidism is associated with insulin resistance. More recently, hypothyroidism has also been linked to decreased insulin sensitivity. The explanation to this apparent paradox may lie in the differential effects of thyroid hormones at the liver and peripheral tissues level. The purpose of this paper is to explore the effects of thyroid hormones in glucose metabolism and analyze the mechanisms whereby alterations of thyroid hormones lead to insulin resistance. 1. Introduction The effects of T4 and T3 have a large impact on glucose homeostasis. This concept was acknowledged by Nobel Prize winner Dr. Bernardo Alberto Houssay in his lecture in 1947 “The blood sugar and the production and consumption of glucose are kept within normal bounds, therefore there is an equilibrium between the glands of internal secretions which reduce the blood sugar (pancreas) and those which raise it (anterohypophysis, adrenals, thyroid, etc.)”. Thyroid hormones exert both insulin agonistic and antagonistic actions in different organs. However, this occurs in a fine balance necessary Continue reading >>

High Thyroid Levels And Insulin Resistance??

High Thyroid Levels And Insulin Resistance??

high thyroid levels and insulin resistance?? high thyroid levels and insulin resistance?? Just a quick question...If you lose weight with your diabetes and have hypothyroidism, but because you lose weight, can the thyroid medication be too much and cause insulin resistance in the end? I seem to have lost whatever good control of my numbers lately, but have lost 17 pounds over 3 1/2 months...somehow I feel like the thyroid is acting up and I have too much medicine going into my body. Can you give me any pointers? The only way to know whether you thyroid is acting up is to go to the doc and have him order some blood work. Thanks Dusty60, I have contacted my doctor and asked him if he would run a thyroid tsh test on me soon. I was diagnosed with hypothyroidism, but have symptoms of hyperthyroidism and feel sort of sick from it. I know it needs checked, and the sooner the better, because it can cause many more problems than just high numbers. D.D. Family Getting much harder to control Are your bs running high at all. know Lloyd reported when his medicine was off he had lots of lows cause he lost weight. D.D. Family T2 for 24 years, pumping 3/07/07,no complications Losing weight caused me to have too high a dose of synthroid, which sped up my metabolism and caused me to have lows. D.D. Family Diagnosed T1 January 2009 MDI (for now) Yes...what you say is true and happened to me. I went through a period of time with insulin resistance and could not figure out why. It dawned on me that my thyroid level may be too high. I lowered the dose after the doctor tested and I was correct. Within a two week period i was able to drop my basal back down and my carb to insulin ratio returned to what it had been prioe. Get your thyroid level tested. Yes, drsoosie my doctor is sending me a s Continue reading >>

Background

Background

Hyperthyroidism is a condition of thyroid hyperfunction and overproduction of thyroid hormones. Autoimmune Graves' disease is the most common cause in young people, especially women, and toxic goitre or toxic adenoma are more common in older individuals. BACKGROUND In 1786 Caleb Perry made the first description of the association between goitre and exophthalmos. In 1835 Graves and in 1840 von Basedow independently described the condition associated with their names. Toxic multinodular goitre (Plummer's disease) was first described in 1913. Graves' disease accounts for nearly 60% of cases of hyperthyroidism, and occurs at a median age which is 20 years younger than patients with adenoma (about 10% of cases), and 10 years younger than multinodular goitre (30% of cases). Adenoma and multinodular goitre have a higher prevalence in iodine-deficient areas than in iodine-sufficient ones[1]. These different groups of patients have different relationship to diabetes. Diabetes is more likely to occur in hyperthyroid patients [2], and glucose intolerance is often present in untreated hyperthyroidism. Autoimmune thyroid disease also frequently occurs within type 1 diabetes (anti-TPO antibodies are present in up to 50% of insulin dependent diabetes mellitus patients) or vice versa, in the Autoimmune Polyendocrine Syndromes[3], due to overlapping HLA associations. Thyroid dysfunction does not cause type 1 diabetes, but patients with Graves' disease are more likely to develop type 1 diabetes, and vice versa. EPIDEMIOLOGY A Japanese study showed that patients on treatment for hyperthyroid Graves’ disease are almost twice as likely to develop type 2 diabetes than members of the general population, are less likely to have been overweight, and are less likely to have a family history of Continue reading >>

Insulin Resistance And Thyroid Disorders.

Insulin Resistance And Thyroid Disorders.

Insulin resistance and thyroid disorders. Endokrynol Pol. 2014;65(1):70-6. doi: 10.5603/EP.2014.0010. Insulin resistance is defined as a glucose homeostasis disorder involving a decreased sensitivity of muscles, adipose tissue, liver and other body tissues to insulin, despite its normal or increased concentration in blood. Insulin resistance may be asymptomatic or occur presenting a variety of disorders, such as: glucose tolerance impairment, type 2 diabetes, as well as hypercholesterolaemia, hypertriglyceridaemia, obesity, and arterial hypertension. Insulin acts via specific receptors present on the surface of most cells of the body. The greatest number of these receptors is found on adipocytes, hepatocytes and striated muscle cells. There are three mechanisms of insulin resistance: pre-receptor, receptor and post-receptor. Multiple methods of assessing insulin resistance are based on the concurrent measurements of glucose and insulin levels in blood serum. The glucose and insulin measurements are conducted in baseline conditions or after intravenous administration of a specific quantity of glucose or insulin. The methods of assessing insulin resistance are divided into direct and indirect. The current 'gold standard' in the assessment of insulin sensitivity is the determination of tissue glucose utilisation using the metabolic clamp technique. The presence of disorders of carbohydrate metabolism has been demonstrated in thyroid disease involving either overt hyperthyroidism or overt hypothyroidism. The severity of the disease is proportional to the severity of these disorders. The possible influence of subclinical forms of both hyperthyroidism and hypothyroidism on carbohydrate disorders is still under discussion. Thyroid hormones have a significant effect on glucose Continue reading >>

Insulin Resistance In Hypothyroid Patients Under Levothyroxine Therapy: A Comparison Between Those With And Without Thyroid Autoimmunity

Insulin Resistance In Hypothyroid Patients Under Levothyroxine Therapy: A Comparison Between Those With And Without Thyroid Autoimmunity

Abstract A chronic inflammation resulting from an imbalance between pro-inflammatory and anti-inflammatory cytokines in Hashimoto’s thyroiditis (HT) might be responsible for IR in hypothyroidism. This study was performed to investigate a probable association between autoimmune background of hypothyroidism and IR. In this clinical study, 63 subjects with Hashimoto’s thyroiditis and 49 subjects with post-ablation hypothyroidism were enrolled. All the participants were euthyroid for more than one year through Levothyroxine therapy. Serum concentrations of Thyroid-stimulating Hormone (TSH), Free Thyroxin (FT4, FT3), Anti-Thyroid Peroxidase Antibodies (Anti-TPO Abs), Total Cholesterol (TC), HDL-Cholesterol (HDL-C), Triglyceride (TG), Fasting Blood Glucose (FBG), and insulin levels were measured and Oral Glucose Tolerance Test (OGTT) was performed for all of the subjects. Participants with anti TPO levels more than 1000 IU /ml were classified as having highly positive antibodies. No significant differences regarding to plasma insulin, glucose and lipid concentration, were detected between subjects with and without Hashimoto’s thyroiditis. However, subjects with highly positive Anti TPO Abs had higher prevalence of elevated fasting insulin level than those with lower titers of Anti TPO Abs and subjects without autoimmune background (94.1% vs. 62.8% and 71.4% respectively, P = 0.05). Subjects with highly positive titers of Abs also had a lower serum HDL-c levels than the rest of the subjects (40.6 ± 2.1 vs. 47.2 ± 1.7 and 47.4 ± 1.4, P = 0.04). There is no obvious association between thyroid autoimmunity and metabolic indexes of hypothyroid patients. Only patients with Ani TPO antibody levels more than 1000 IU/ml may experience higher insulin level and less HDL-c with Continue reading >>

Blood Sugar, Insulin, And Thyroid

Blood Sugar, Insulin, And Thyroid

Insulin and blood sugar can effect your thyroid in 4 main ways; they can effect adrenal hormones, inflammation, your gut and autoimmunity. Dr. Ruscio discusses how you can identify if any of these are effecting your thyroid health and what you can do address to fix it. Subscribe to Dr. Ruscio’s YouTube account Blood Sugar, Insulin, And Thyroid Dr. Michael Ruscio: Hi. This is Dr. Ruscio, and welcome to the next video in our Thyroid Solution Series, the hidden cause of hyperthyroidism Number 2: Insulin, blood sugar and your thyroid. Insulin and blood sugar can affect your thyroid through four main mechanisms: they are through manipulation of your stress hormones, through modulating inflammation, through causing digestive problems, and through worsening autoimmunity. Now just as a review, what is blood sugar? What is Insulin? When we ingest food, mainly carbohydrate, that carbohydrate, that sugar gets turned, gets absorbed into blood sugar, thus making ones blood sugar levels go up. Insulin is then released to push sugar from the blood steam into your cells, thus lowering your blood sugar. So you eat, blood sugar goes up, body released insulin, insulin pushes sugar into cells, and then blood sugar levels come down. So what is the connection between blood sugar and stress hormones and your thyroid. Well, blood sugar levels have a profound impact on your stress hormones and stress hormones have a very strong impact on your thyroid. Now specifically when one ingests too much carbohydrates – this may be a bowl of cereal, and a glass of orange juice and maybe a banana for breakfast for example. Which is way too much carbohydrate for someone to ingest in a meal. This will cause blood sugar levels to go high, as you see in this graph. This high blood sugar will give some peop Continue reading >>

Thyroid Dysfunction And Insulin Resistance

Thyroid Dysfunction And Insulin Resistance

Endocrine Abstracts (2016) 41 EP1055 | DOI: 10.1530/endoabs.41.EP1055 Thyroid dysfunction and insulin resistance Author affiliations View ePoster Download ePoster Background Insulin resistance (IR) is a state in which a given concentration of insulin produces biological effect less than expected and IR actually make up a broad clinical spectrum, including obesity, glucose intolerance, DM, and the metabolic syndrome that are associated with various endocrine, metabolic, & genetic conditions. There is an association of IR with thyroid abnormalities. Evidence for a relationship between T4 and T3 and glucose metabolism appeared over 100 years ago when the influence of hyperthyroidism in the deterioration of glucose metabolism was first noticed. More, hypothyroidism has been linked to decreased IR. Thyroid hormones exert both insulin agonistic and antagonistic actions in different organs. However, this occurs in a fine balance necessary for normal glucose metabolism. Deficit or excess of thyroid hormones can break this equilibrium leading to alterations of carbohydrate metabolism. The aim of this study was to determine the association between thyroid function and IR. Methodology this study included 90 non diabetic patients recruited from Fayoum university hospital 30 patients had hypothyroidism, 30 had hyperthyroidism & 30 were euthyroid. HOMA IR were calculated. Our results revealed, 50% of hypothyroid patients, 36% of hyperthyroid patients & only 16.5% of the euthyroid patients had IR (P=0.024). The mean body weight of the hyperthyroid group was (73.38.7) was significantly lower than that of the euthyroid group (84.89.2) and the hypothyroid group (86.711.3) (P<0.001). The mean BMI of the Hypothyroid patients was higher (32.14.4) than the euthyroid group (30.13.9) & the hy Continue reading >>

Insulin Resistance And Thyroid Health

Insulin Resistance And Thyroid Health

Insulin resistance occurs when the body becomes resistant to the effects of insulin. This is almost always caused by diet, and if unaddressed can eventually lead to type II diabetes. Many people with thyroid and autoimmune thyroid conditions have insulin resistance, and the good news is that this condition can be reversed. In fact, many times type II diabetes can also be reversed through natural methods. Before talking more about insulin resistance, it’s probably a good idea to briefly discuss the role of insulin. Insulin is produced in the pancreas, specifically within the beta cells of the islets of Langerhans. Many people know that insulin is given to many diabetics to help lower their blood sugar levels. So without question, insulin plays a very important role in helping to balance the blood sugar levels. But in addition to this, it also has other functions. For example, insulin plays a role in DNA replication and protein synthesis. It also plays a role in lipid synthesis, along with the uptake of amino acids. Insulin also is important for the health of the liver. And many of you know that a great deal of the conversion of T4 to T3 takes place in the liver. As a result, if someone has insulin resistance, then this can potentially cause problems with the conversion of T4 to T3. Signs and Symptoms of Insulin Resistance Some of the signs and symptoms associated with insulin resistance include sugar cravings, fatigue, and weight gain. Of course many people with thyroid and autoimmune thyroid conditions have these symptoms, and they’re not always related to insulin resistance. So it can take some detective work to determine if someone has this problem. How does insulin resistance develop? As briefly mentioned earlier, eating a poor diet is the main cause. Although th Continue reading >>

Hypothyroidism And Insulin Resistance [4 Steps To Reverse It And Finally Lose Weight]

Hypothyroidism And Insulin Resistance [4 Steps To Reverse It And Finally Lose Weight]

Do you feel like it's impossible to lose weight with Hypothyroidism? ​It actually isn't impossible and I will explain how later, but first I need to share a story with you. ​I had a patient who came to see me in the office recently. She was 43, on levothyroxine (for years), about 60 pounds overweight, and wanted my help in balancing her hormones and help her lose some of that weight. ​ Like most other people, she had tried to lose weight following every diet you can think of, but nothing seemed to work for her. So I got to testing her labs. Know what I found? ​ Insulin resistance. ​ And THAT was her primary problem. Her thyroid wasn't all that bad, she ultimately did better on Armour thyroid - but her main problem was the insulin. Once we got her on the right regimen, cleaned up her diet, fixed her adrenals, replaced nutrient deficiencies and put her on a fasting program her weight started to shed off. And that's what we are going to talk about today. ​Hypothyroidism and Insulin Resistance. And why it's impossible to lose weight unless you address BOTH issues. What is Insulin Resistance? ​Insulin is the hormone that increases after you eat a lot of sugar. It puts sugar inside your cells and protects your body from high levels of sugar in the blood. That's what it's supposed to do - when everything is working correctly. When insulin levels remain chronically elevated (like when we eat a lot of sugar in our diet), your body becomes resistant to insulin. And that's where all the problems start. High levels of insulin cause you to store the calories you eat from your diet as fat in your belly. ​So high levels of insulin = you gain weight (even if you eat fewer calories). I've put together a list of some symptoms I see in my patients that have insulin resista Continue reading >>

Insulin Action In Hyperthyroidism: A Focus On Muscle And Adipose Tissue

Insulin Action In Hyperthyroidism: A Focus On Muscle And Adipose Tissue

Insulin Action in Hyperthyroidism: A Focus on Muscle and Adipose Tissue Hellenic National Center for Research, Prevention, and Treatment of Diabetes Mellitus and Its Complications (P.M., S.A.R.), 10675 Athens, Greece; Search for other works by this author on: Hellenic National Center for Research, Prevention, and Treatment of Diabetes Mellitus and Its Complications (P.M., S.A.R.), 10675 Athens, Greece; Second Department of Internal Medicine (S.A.R., G.D.), Research Institute and Diabetes Center, Athens University Medical School, Attikon University Hospital, GR-12462 Athens, Greece Search for other works by this author on: Second Department of Internal Medicine (S.A.R., G.D.), Research Institute and Diabetes Center, Athens University Medical School, Attikon University Hospital, GR-12462 Athens, Greece Address all correspondence and requests for reprints to: Professor George Dimitriadis, M.D., D.Phil., Second Department of Internal Medicine, Research Institute and Diabetes Center, Athens University Medical School, Attikon University Hospital, 1 Rimini Street, GR-12462 Athens, Greece. Search for other works by this author on: Endocrine Reviews, Volume 31, Issue 5, 1 October 2010, Pages 663679, Panayota Mitrou, Sotirios A. Raptis, George Dimitriadis; Insulin Action in Hyperthyroidism: A Focus on Muscle and Adipose Tissue, Endocrine Reviews, Volume 31, Issue 5, 1 October 2010, Pages 663679, Hyperthyroidism leads to an enhanced demand for glucose, which is primarily provided by increased rates of hepatic glucose production due to increased gluconeogenesis (in the fasting state) and increased Cori cycle activity (in the late postprandial and fasting state). Adipose tissue lipolysis is increased in the fasting state, resulting in increased production of glycerol and nonesterif Continue reading >>

New Insight Into The Pathogenesis Of Insulin Resistance In Hyperthyroidism And Hypothyroidism El Demellawy Hh, El Feky Ma, Shoier Ra, Shaker Og - Egypt J Intern Med

New Insight Into The Pathogenesis Of Insulin Resistance In Hyperthyroidism And Hypothyroidism El Demellawy Hh, El Feky Ma, Shoier Ra, Shaker Og - Egypt J Intern Med

Both hypo and hyperthyroidism were associated with insulin resistance and disturbances in lipid profiles. Keywords:Hypothyroidism, hyperthyroidism, adiponectine, HOMAIR, cholesterol and HDL El Demellawy HH, El Feky MA, Shoier RA, Shaker OG. New insight into the pathogenesis of insulin resistance in hyperthyroidism and hypothyroidism. Egypt J Intern Med 2013;25:191-5 El Demellawy HH, El Feky MA, Shoier RA, Shaker OG. New insight into the pathogenesis of insulin resistance in hyperthyroidism and hypothyroidism. Egypt J Intern Med [serial online] 2013 [cited2018 Apr 29];25:191-5. Available from: Thyroid disease, namely, hypothyroidism and hyperthyroidism, constitutes the most common endocrine abnormality in populations aged at least 12 years [1] . Thyroid disease is associated with various metabolic abnormalities because of the effects of thyroid hormones on almost all the major metabolic pathways [2] . Thyroid hormones regulate the basal energy expenditure through their effect on protein, carbohydrate, and lipid metabolism [3] . Whereas thyroid hormones oppose the action of insulin and stimulate hepatic gluconeogenesis and glycogenolysis, they upregulate the expression of genes such as glucose transporter type 4 and phosphoglycerate kinase, involved in glucose transport and glycolysis, thus acting synergistically with insulin, facilitating glucose disposal and utilization in peripheral tissues [4] . The prevalence of thyroid disease in patients with diabetes is significantly higher than that in the general population [5] . This indicates a possible interplay between thyroid status and insulin sensitivity. Patients with thyroid diseases usually show changes in body weight, appetite, and thermogenesis [6] . Hypothyroid patients gain weight, with decreased thermogenesis and Continue reading >>

High Blood Sugar & Insulin Resistance Correlate With High T3

High Blood Sugar & Insulin Resistance Correlate With High T3

High blood sugar, insulin resistance, or high fasting blood glucose may all be caused by high T3 levels. Many on the T3-only protocol or high doses of desiccated thyroid notice their blood sugar levels rising and wonder why. It’s because thyroid levels, either too high or too low, have a direct impact on blood glucose. Hypothyroidism may cause high blood sugar & insulin resistance A1C levels of hypothyroid patients are generally higher than normal, and in one study, replacement with thyroid hormone brought the A1C down, but it did not lower fasting blood glucose. [1] A1C is a measure of average blood glucose levels over several months. This study shows that the hypothyroid condition will cause an overall higher average blood glucose than normal. Insulin resistance appears when thyroid levels are too low or too high. [2] Correcting the hypothyroid state is beneficial, but replacement with too much thyroid hormone may result in continued insulin resistance. A low T3/T4 ratio was found in pre-diabetics who had both high insulin levels and insulin resistance. These subjects had lower T3 levels and higher T4 levels than normal, glucose-tolerant subjects. This study confirms that a certain level of T3 is essential for normal glucose metabolism.[3] SHBG (Sex Hormone Binding Globulin) is secreted by the liver and is positively correlated with thyroid levels—it rises when hyperthyroid and falls when hypothyroid. Low levels therefore suggest a hypothyroid condition. Low SHBG is also a biomarker of insulin resistance, metabolic syndrome, and a risk factor for developing high blood sugar and type 2 diabetes, especially in women. [5] High T3 & High T4 may cause high blood sugar and insulin resistance Blood sugar problems may be caused by high thyroid levels. The following are so Continue reading >>

Influence Of Thyroid Hormone Level On Insulin Action In Human Adipose Tissue

Influence Of Thyroid Hormone Level On Insulin Action In Human Adipose Tissue

The relationship between the levels of circulating thyroid hormones and the action of insulin on adipose tissue was investigated in 6 hypothyroid patients and 6 hyperthyroid patients, all untreated, and 8 healthy control subjects. All were matched for age, body weight, and fat cell size. Gluteal s.c. adipose tissue was used. The insulin receptor number in isolated adipocytes was increased by 70% in hypothyroldism and decreased by 40% in hyperthyroidism. The sensitivities of the effects of insulin on lipolysis and glucose oxidation were increased fourfold in hypothyroidism and decreased fivefold in hyperthyroidism. The maximum insulin-induced glucose oxidation (insulin responsiveness) was inhibited by 60% in hypothyroidism and enhanced by 180% in hyperthyroidism. The thyroid hormone concentration was significantly correlated with insulin receptor number (r = −0.72), insulin responsiveness (r = 0.71), and insulin sensitivity (r = −0.75). It is suggested that thyroid hormones regulate the effect of insulin on adipose tissue, which occurs at the receptor and postreceptor levels of insulin action. The effects of ischemia at varying temperatures on the survival of fetal islet endocrine cells was investigated by placing 17-day-old fetal mouse pancreata in organ culture after 2, 4, or 6 h at either 4°C, 22°C, or 37°C. Insulin secretion by the cells in vitro, the content of insulin in the cultured pancreata, and the ability of the cultured islets to reverse diabetes in syngeneic streptozotocin-diabetic mie were assessed. Fetal pancreas subjected to 2–6 h of ischemia at either 4°C or 22°C showed neither loss of insulin secretory capacity in vitro nor loss of ability to produce large functional grafts, and behaved identically to tissue not subjected to deliberate ischem Continue reading >>

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