triiodothyronine--reverse and Acidosis

The influence of the acidotic state on the thyroxine (T4) peripheral metabolism was studied in two different forms of metabolic acidosis, ie infantile diarrhea and diabetic ketoacidosis. The serum concentrations of T4, free T4 (FT4), triiodothyronine (T3), reverse T3 (rT3), thyrotropin (TSH) and thyroxine-binding globulin (TBG) were measured and compared to healthy control groups. Lower T4 and T3 and higher rT3 serum concentrations were found in both tested groups of patients in relation to the control groups. In infants with severe metabolic acidosis FT4 values were lower than those observed in the control group. In addition, serum TBG levels were lower in diabetic patients as compared to control subjects. Despite the reduced serum T3 and T4 concentrations in both groups of patients, TSH concentrations, were within the normal range. Therefore, we concluded that acidosis caused either by diarrhea (not so far described) or by diabetes mellitus (well documented up to now) affects the thyroid hormones metabolism in a similar way, at least as far as the thyroid hormones blood levels are concerned.

Topics: Acidosis; Adolescent; Child; Child, Preschool; Female; Humans; Infant; Male; Thyroid Hormones; Thyrotropin; Thyroxine; Thyroxine-Binding Proteins; Triiodothyronine; Triiodothyronine, Reverse

The effects of acute acidosis on neonatal thyroid function were studied by infusing HCl for 4 h in 42 to 54-h-old lambs. Animals of the same age, used as controls, were simultaneously infused with physiological saline. HCl infusion induced a sharp decrease in blood pH and total restoration did not occur before 48 h. When compared to control lambs, this experimental acidosis was associated with slight, but significant, decreases in plasma TSH, total T4, free T4 and total T3 levels, and in values of the free T4/total T4 ratio; the T3/FT4 ratio was not affected. The values of RT3/FT4 ratio were significantly increased in acidotic lambs. It is concluded that acidosis induced only modest secretory changes in neonatal thyroid function and slightly reduced the proportion and the amount of free T4.

Topics: Acidosis; Animals; Animals, Newborn; Hydrochloric Acid; Sheep; Thyrotropin; Thyroxine; Triiodothyronine; Triiodothyronine, Reverse