[Studies on nonthyroidal illness after heart surgery]

The concentrations of pituitary hormones (TSH and PRL), thyroid hormones (free-T4 and free-T3), thyroid hormone binding protein (TBG) and lipids (TG and FFA) in the blood were measured in order to examine the physiology of nonthyroidal illnesses that occurred as a result of heart surgery as well as their effects on the pituitary and thyroid glands. The subjects of the study consisted of 30 adults with congenital and acquired heart disease. Blood concentrations of TSH, PRL, free-T4, free-T3, and TBG decreased, and those of FFA increased, on the 2nd day following surgery. On the 2nd day following surgery, the decrease in the concentrations of free-T4 and free-T3 in the blood were considered due to a decrease in secretion of T4 from the thyroid gland, as well as due to a decrease in the activity of iodothyronine 5'-deiodinase in the peripheral organs. In the 3rd week following surgery, the concentrations of these items returned to their original values on the day prior to surgery.