triiodothyronine--reverse and Diabetes-Mellitus

Topics: Adrenal Gland Diseases; C-Peptide; Diabetes Mellitus; Dwarfism; Glucagon; Growth Hormone; Humans; Insulin; Parathyroid Diseases; Radioimmunoassay; Thyroglobulin; Thyroid Diseases; Thyroxine; Thyroxine-Binding Proteins; Triiodothyronine; Triiodothyronine, Reverse

Several alterations in thyroid function are found in diabetes mellitus (see Table I). The most profound changes occur in patients with insulin-dependent diabetes. Plasma T4 is normal whereas plasma T3 is diminished, and the plasma level of rT3 is elevated in diabetic ketoacidosis or in patients with severely uncontrolled diabetes. These changes arise from alterations in the monodeiodination pathways of T4. Both hypo- and hyperthyroidism occur with increased frequency in diabetes. There is an increased prevalence of thyroid autoantibodies in insulin-dependent diabetics. Animals studies suggest a defect in the hypothalamic regulation of the thyroid-pituitary feedback system and an impaired response of the thyroid gland to TSH. Clinical studies are not yet available to confirm the occurrence of these regulatory disturbances in human diabetic patients. It is not clear whether the deiodination and regulatory changes in thyroid hormone economy that are associated with diabetes result in hypothyroidism at the cellular level.

Topics: Animals; Autoantibodies; Diabetes Complications; Diabetes Mellitus; Diabetes Mellitus, Experimental; Humans; Hyperthyroidism; Hypothalamo-Hypophyseal System; Hypothyroidism; Insulin; Receptors, Cell Surface; Receptors, Thyroid Hormone; Thyroid Gland; Thyrotropin; Thyrotropin-Releasing Hormone; Thyroxine; Triiodothyronine; Triiodothyronine, Reverse

The clinical implications of nuclear T3R alterations of circulating lymphocytes in hyperthyroidism, hypothyroidism and nonthyroidal diseases were investigated. Nuclear T3R in lymphocytes was determined by radio-ligand binding analysis. The results showed that in hyper- and hypothyroid patients the nuclear affinity (Ka) for T3 was similar to that of normal subjects. In hyperthyroidism nuclear T3 maximal binding capacity (MBC) was unaltered, whereas in hypothyroidism the MBC was significantly increased. In the patients with diabetes mellitus, chronic renal failure and hepatic cirrhosis, the nuclear T3R MBC of lymphocytes was about 1.5-1.6 times of the normal controls. It was concluded that there existed hormonal regulation of nuclear T3R, and up-regulation was seen in hypothyroidism and low T3 syndrome.

Topics: Diabetes Mellitus; Graves Disease; Humans; Hypothyroidism; Kidney Failure, Chronic; Lymphocytes; Receptors, Thyroid Hormone; Triiodothyronine, Reverse

Topics: Blood Glucose; Chromatography, Affinity; Diabetes Mellitus; Diabetic Nephropathies; Fructosamine; Glycated Hemoglobin; Hexosamines; Humans; Kidney Failure, Chronic; Peritoneal Dialysis, Continuous Ambulatory; Triiodothyronine, Reverse

Several previous studies have reported that serum T3 and reverse T3 (rT3) concentrations are altered in uncontrolled diabetes mellitus and their normalization occurs when euglycemia is achieved. Therefore, this study was undertaken to examine the usefulness of serum T3 and rT3 levels as indices of metabolic control in diabetes mellitus. Serum T3, rT3, T4, Free T4, TSH and T3 resin uptake were determined in 18 normal subjects and 35 patients with newly discovered diabetes mellitus before initiation of therapy and reassessed after normalization of glycosylated hemoglobin (HbA1) concentration. These thyroid hormone concentrations were compared to the well established parameters of metabolic control such as fasting plasma glucose (FPG), peak plasma glucose (PPG), area under the curve of the oral glucose tolerance test (sigma G), 24 hr urinary glucose level (UG), HbA1 as well as glycosylated protein (GlyPr) and glycosylated albumin (GlyAlb) concentrations. Serum T4, T3RU, Free T4 and TSH concentrations in patients with diabetes mellitus prior to treatment were not significantly different from normal subjects and were not significantly correlated with any of the parameters of diabetic control. Serum T3 was significantly lower and serum rT3, significantly higher in diabetic patients prior to treatment as compared to normal subjects and both T3 and rT3 normalized in 20 patients studied when adequate metabolic control was achieved as reflected by normalization of HbA1 (less than 8.2%). Furthermore, significant negative and positive correlations were noted between parameters of metabolic control and serum T3 and rT3 levels respectively. Therefore, this study demonstrates that serum T3 and rT3 may be reliable indices of metabolic control in diabetes mellitus.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Blood Glucose; Diabetes Mellitus; Glucose Tolerance Test; Glycated Hemoglobin; Humans; Lipids; Thyrotropin; Thyroxine; Triiodothyronine; Triiodothyronine, Reverse

Topics: Aging; Diabetes Mellitus; Female; Humans; Immune System Diseases; Infections; Neoplasms; Pregnancy; Thyroid Hormones; Thyrotropin; Thyroxine; Thyroxine-Binding Proteins; Triiodothyronine, Reverse

Fasting and hypocaloric diets are known to induce a reduction of triiodothyronine (T3) and to increase reverse triiodothyronine (rT3) in normal and obese subjects. The effect of 8-day fasting was evaluated on T3, thyroxine (T4), free T4, rT3, TSH, immunoreactive insulin (IRI), thyroxine binding globulin (TBG) and glycemia in 21 obese subjects (5 males, 16 females) grouped according to the average starting blood glucose concentration in: group I, diabetic obese subjects (9 patients); group II, non diabetic obese subjects (12 patients). All patients had no history of recent weight loss due to dietetic therapy or drugs. Blood samples were drawn in the morning at 0, 2, 4, 6, 8 days after total caloric deprivation and 2 days after refeeding. A superimposable variation of weight and glucose concentration were seen in both groups. In addition, no difference was observed in ketone body excretion, SH, TBG, T4, free T4. In group II a significant decrease of IRI was observed during diet (p less than 0.05); T3 decreased (p less than 0.01) and rT3 increased (p less than 0.01) significantly. No variations in T3 and rT3 values were observed in group I. These results are consistent with a possible role of glucose metabolism in the genesis of the low T3 syndrome.

Topics: Adult; Diabetes Mellitus; Fasting; Female; Humans; Insulin; Male; Middle Aged; Obesity; Thyroglobulin; Thyroid Hormones; Thyrotropin; Thyroxine; Triiodothyronine; Triiodothyronine, Reverse

Plasma TSH, total and free T3 and T4, reverse T3, blood pH, HbAlc, ketonuria and glycosuria were evaluated in 8 subjects with diabetic ketoacidosis, in 54 diabetics of group 1 and group 2 without severe metabolic derangement and in 10 control women. The diabetics with ketoacidosis showed before intensive therapy low T3, total and free, and high reverse T3 concentrations as compared to controls (unpaired t-test, p less than 0.001). After one day of intensive therapy the decrease of hyperglycemia and pH increase (p less than 0.001, paired t-test), glycosuria and ketonuria are not related to significant variations of iodothyronines and TSH. The significant variations (paired t-test, p less than 0.001) in total and free T3 and in reverse T3 concentrations were found only six days after remission of ketoacidosis. In diabetics (type 1 and 2) without recent history of ketoacidosis no differences were found in mean total and free T3 and T4, in reverse T3 and in plasma concentrations although mean blood glucose and HbAlc were statistically different (t-test, p less than 0.001). The changes in serum T3 (total and free) and reverse T3 are useful indicators of total metabolic control during the management of diabetic ketoacidosis.

Topics: Adult; Blood Glucose; Diabetes Mellitus; Diabetic Ketoacidosis; Female; Humans; Hydrogen-Ion Concentration; Male; Middle Aged; Thyrotropin; Thyroxine; Triiodothyronine; Triiodothyronine, Reverse

Topics: Diabetes Mellitus; Glucose Tolerance Test; Humans; Kidney Failure, Chronic; Thyroid Gland; Triiodothyronine; Triiodothyronine, Reverse

In 45 type 2 diabetics it was unable to be found a relation between the plasma lipids and the fasting blood glucose (G), HbA1c, reverse T3 (rT3), rT3/T3 ratio, and relative body weight (R.B.W.). The conclusion was reached that the alteration of the lipoprotein metabolism and the thyroid hormones in type 2 diabetics could be primitive and independent from the availability of the insulin.

Topics: Adult; Body Weight; Cholesterol; Diabetes Mellitus; Female; Glycated Hemoglobin; Humans; Insulin; Lipoproteins; Male; Triglycerides; Triiodothyronine; Triiodothyronine, Reverse

Topics: C-Peptide; Diabetes Mellitus; Humans; Islets of Langerhans; Triiodothyronine; Triiodothyronine, Reverse

Topics: Adolescent; Adult; Aged; Diabetes Mellitus; Diabetic Ketoacidosis; Female; Humans; Male; Middle Aged; Thyrotropin; Thyrotropin-Releasing Hormone; Thyroxine; Triiodothyronine; Triiodothyronine, Reverse

Topics: Diabetes Mellitus; Humans; Triiodothyronine; Triiodothyronine, Reverse

In 21 type 1 diabetics a significative positive correlation was found between plasma triglycerides (TG) and fasting blood glucose (G), HbA1c, reverse T3 (rT3), rT3/T3 ratio and relative body weight (R.B.W.); total cholesterol (C) and HDL-cholesterol (HDL-C) were not correlated. If you consider the R.B.W. during the correlation between TG and the other laboratory tests, the only correlation that remains significant is that between TG and HbA1c. Plasma hyperTG found in type 1 diabetics appears to depend upon poor diabetic control and overweight; HDL-C is within normal limits because the removal of TG was slightly involved.

Topics: Adolescent; Adult; Blood Glucose; Body Weight; Diabetes Mellitus; Female; Glycated Hemoglobin; Humans; Male; Middle Aged; Triglycerides; Triiodothyronine; Triiodothyronine, Reverse

The effects of diabetes mellitus on serum thyroid hormone parameters were studied in 54 patients divided into 4 groups. Treated asymptomatic patients (group I) had normal thyroid values which did not correlate with serum or urinary glucose. Untreated nonketoacidotic patients (group II) showed a mild persistent depression in T3 and an elevation in rT3. Patients with ketoacidosis with a brief history of symptoms (group III) had a moderate T3 decrease and a mild rT3 elevation which quickly resolved with treatment. Ketoacidotic patients with a long history of symptoms (group IV) had marked depression of T3 and elevation of rT3 which was only partially rectified by treatment. Serum T4 was generally normal, except for a minimal decrease on the day after admission, probably resulting from rehydration and a subsequent increase associated with an increase in TSH. We concluded that thyroid hormone parameters were not influenced by variations in serum glucose, but seemed to reflect the effects of a preexisting catabolic state, ketoacidosis, or both.

Topics: Adult; Blood Glucose; Diabetes Mellitus; Diabetic Ketoacidosis; Humans; Insulin; Kinetics; Middle Aged; Thyroid Hormones; Thyrotropin; Thyroxine; Triiodothyronine; Triiodothyronine, Reverse

Basal plasma levels of thyroxine (T4), triiodothyronine (T3) and reverse T3 were determined by radioimmunoassay in 44 control subjects, 44 Type 1 (insulin-dependent) and 39 Type 2 (non insulin-dependent) diabetic patients aged from 15 to 75 years. All were clinically euthyroid. The quality of diabetic control was assessed by the percentage of glycosylated haemoglobin. In both the diabetic groups there was a significant decrease in T3 and a rise in reverse T3 whereas T4 was normal. We found no significant differences between plasma thyroid hormone levels in Type 1 and Type 2 diabetic patients. In the poorly controlled diabetics (glycosylated haemoglobin greater than or equal to 12%), T3 was 90 +/- 5 ng/dl, which differed significantly from the level found in the better controlled patients (106 +/- 5 ng/dl, p less than 0.01). In the diabetic patients without associated illness, a negative linear correlation was found between T3 and glycosylated haemoglobin and a positive correlation between reverse T3/T3 and glycosylated haemoglobin. No correlation between T3 or reverse T3 and fasting blood glucose could be established. In conclusion, many diabetics showed a low T3 syndrome suggesting that there may be an impairment in the extrathyroidal conversion of T4 to T3. This may well be enhanced by a poor diabetic control (glycosylated haemoglobin greater than or equal to 12%).

Topics: Adolescent; Adult; Diabetes Mellitus; Diabetic Ketoacidosis; Female; Glycated Hemoglobin; Humans; Male; Middle Aged; Thyroid Hormones; Thyroxine; Triiodothyronine; Triiodothyronine, Reverse

Topics: Adult; Aged; Blood Glucose; Diabetes Mellitus; Humans; Insulin; Male; Middle Aged; Thyroxine; Triiodothyronine; Triiodothyronine, Reverse

Topics: Aged; Blood Glucose; Diabetes Mellitus; Glucose; Humans; Insulin; Male; Middle Aged; Thyrotropin; Thyroxine; Triiodothyronine; Triiodothyronine, Reverse