The effect of surgery with carbohydrate infusion on circulating triiodothyronine and reverse triiodothyronine.

The blood levels of thyrotrophin (TSH), thyroxine (T4), triiodothyronine (T3), and reverse triiodothyronine (rT3) were measured in a group of patients undergoing cholecystectomy and receiving 2000 kcal of glucose daily throughout the study. TSH changes suggested a peroperative peak followed by a fall and subsequent rise. T4 showed no significant changes. T3 fell and rT3 rose postoperatively, with a highly significant fall in the T3/rT3 ratio (p less than 0.001). Surgery and carbohydrate deprivation separately result in similar changes. However, the demonstration of the changes after injury despite adequate carbohydrate intake strongly suggests that they are a primary response to surgery and not a secondary response to the normal consequential fall in caloric and carbohydrate intake. The changes could be an appropriate adaptation to the changed metabolic requirements.