triiodothyronine--reverse and Alcoholism

Effects of recent alcoholic withdrawal on thyroxine (T4), 3,5,3'-triiodothyronine (T3), and reverse T3 (rT3) metabolism were determined by serum tracer kinetic studies in recently abstinent alcoholics without overt hepatocellular injury or caloric deprivation. Data were compared with those of normal subjects using a three-pool model, with rapidly and slowly equilibrating pools exchanging with serum. Significant differences included 1) reduced serum total rT3 levels (to 69% of normal) and rT3 degradation rates (to 61%); 2) increased rT3 binding in rapidly (to 557%) but reduced binding in slowly (to 13%) equilibrating tissues, with opposite effects on rT3 fractional transfer rates to serum from rapidly (to 7.5%) and slowly equilibrating sites (to 669%); 3) increased T4 fractional transfer rates from serum to rapidly equilibrating tissues (to 122%); and 4) increased T4 binding to both rapidly (to 195%) and slowly (to 190%) equilibrating tissues. T3 kinetics were not significantly altered. Thus recently abstinent alcoholics have hormone-specific alterations of T4, T3, and rT3 transfer, distribution, and metabolism distinct from other nonthyroidal illnesses or caloric deprivation. Furthermore, these data indicate separate transfer processes for T4, T3, and rT3 from serum to tissue sites and hormone-specific tissue binding characteristics in humans in vivo.

Topics: Adult; Alcoholism; Ethanol; Female; Humans; Male; Middle Aged; Models, Biological; Reference Values; Substance Withdrawal Syndrome; Thyroxine; Tissue Distribution; Triiodothyronine; Triiodothyronine, Reverse

Endocrinological tests were performed in 14 chronic alcoholic men with signs of intellectual impairment and/or peripheral neuropathy. All had been abstinent from alcohol for at least 1 month. Basal serum growth hormone (GH) was consistently increased in only one patient whereas the GH responses to insulin hypoglycemia stimulation was normal in all patients. Thyroid function values (T4, T3, rT3, TSH) were normal in all patients whereas baseline serum prolactin values were significantly increased in alcoholics as compared with a control group. In a combined TRH- and GnRH-stimulation tests, GH-responses were also normal whereas TSH and prolactin responses were blunted or absent in about half of the patients, the responses correlating significantly (p less than 0.01). It is concluded that disturbances in the hypothalamic-pituitary axis may occur in chronic alcoholics with nervous impairment independently of the physical deterioration, which often is associated with chronic alcoholism.

Topics: Adult; Alcohol Amnestic Disorder; Alcoholism; Blood Glucose; Gonadotropin-Releasing Hormone; Growth Hormone; Humans; Hypothalamo-Hypophyseal System; Insulin; Male; Peripheral Nervous System Diseases; Prolactin; Thyroid Gland; Thyrotropin; Thyrotropin-Releasing Hormone; Thyroxine; Triiodothyronine; Triiodothyronine, Reverse

In a chronic feeding study adult male Fischer-344 rats (n = 12) were fed a nutritionally complete liquid diet containing 10% (w/v) ethanol for 40 days while control animals (n = 12) were pair fed a nutritionally complete isocaloric diet in which dextrose was substituted for ethanol. Treated animals were gradually introduced to and withdrawn from the 10% diet. At the end of the study and at sacrifice ethanol-fed rats had gained slightly more weight than pair-fed controls. They also showed a significant decrease in total thyroxine, free thyroxine, L-triiodothyronine, reverse L-triiodothyronine, and basal thyroid-stimulating hormone. These differences did not appear to result from caloric deprivation alone. Possible explanations for some of these thyroidal changes are discussed.

Topics: Alcoholism; Animals; Hypothalamo-Hypophyseal System; Male; Rats; Rats, Inbred F344; Thyroid Gland; Thyroid Hormones; Thyrotropin; Thyrotropin-Releasing Hormone; Triiodothyronine; Triiodothyronine, Reverse

Nine greyhound dogs were fed ethanol for 1 year to examine the effects of long-term ethanol feeding on circulating thyroid hormones. The dose of ethanol consumed per day was 2 gm/kg for the first month, 3 gm/kg for the second month, and 4 gm/kg for the rest of the study. Plasma triiodothyronine (T3), thyroxine (T4), and reverse triiodothyronine (rT3) were measured by radioimmunoassay. Plasma T3 and T4 concentrations increased significantly during the period of ethanol administration compared with control values (ANOVA, P less than 0.005). Levels of rT3 showed a trend to increase, although this was not significant. Resin T3 uptake decreased significantly (ANOVA, P less than 0.005) and the calculated free T4 index and free T3 index showed significant elevations (ANOVA, P less than 0.005) during ethanol administration. The results of this study indicate that long-term ethanol feeding to dogs induces an increase in circulating thyroid hormones.

Topics: Alcoholism; Analysis of Variance; Animals; Blood Proteins; Dogs; Humans; Liver Diseases, Alcoholic; Protein Binding; Thyroid Hormones; Thyroxine; Triiodothyronine; Triiodothyronine, Reverse

Chronic alcoholics who had been abstinent from alcohol for more than 2 years were evaluated with the thyrotropin-releasing hormone (TRH) test. The findings suggest the following profound disturbances in the hypothalamic-pituitary-thyroid axis: 1) a "euthyroid sick syndrome," evidenced by low levels of triiodothyronine (T3), high levels of reverse T3, and normal levels of thyroxine (T4) (this syndrome implies a decreased 5'-deiodination of T4 to T3 and of reverse T3 to its lesser iodinated metabolites), 2) an increased binding capacity for thyroid hormones, evidenced by a decreased T3-uptake value and an increased level of T4-binding globulin, and 3) thyroid-stimulating hormone (TSH) blunting in 31% of patients. Paradoxically, there was a positive correlation between basal T4 and delta max TSH in subjects with blunted TSH, but baseline TSH levels were reduced in subjects with and without blunted TSH.

Topics: Adult; Aged; Alcohol Drinking; Alcoholism; Depressive Disorder; Growth Hormone; Humans; Male; Middle Aged; Prolactin; Thyrotropin; Thyrotropin-Releasing Hormone; Thyroxine; Triiodothyronine; Triiodothyronine, Reverse

Alcohol and alcohol withdrawal may affect nutritional status in many different ways, including effects on thyroid activity. The influence of alcohol withdrawal on thyroid hormone economy was investigated by measurements of changes in the serum concentrations of thyroxine (T4), 3, 5, 3'-triiodothyronine (T3), 3, 5, 5'-triiodothyronine (reverse T3, rT3), and thyrotropin (TSH) in chronic alcoholics experiencing different degrees of alcohol abstinence. In addition, the serum concentrations of ethanol were measured at entrance. There was no significant correlation between the entrance serum ethanol levels, on the one hand, and those of T4, T3, rT3, or TSH, on the other. However, during severe ethanol abstinence (with or without delirium tremens), there was a significant increase in the serum levels of T4 and rT3, but not in those of T3 and TSH. These findings indicate that (severe) alcohol abstinence can interfere with thyroid hormone economy, either by enhancing thyroid hormone secretion or by reducing T4 and rT3 deiodination. It is an open question whether this represents a beneficial adaptation to the metabolic disturbance caused by alcohol intoxication and abstinence, or an additional derangement that warrants nutritional or other therapeutic measures.

Topics: Alcohol Withdrawal Delirium; Alcoholism; Humans; Substance Withdrawal Syndrome; Thyroid Hormones; Thyrotropin; Thyroxine; Triiodothyronine; Triiodothyronine, Reverse