Changes in thyroid hormones in obese women following jejuno-ileal bypass surgery

The serum concentrations of thyroxine (T4), 3,5,3'-triiodothyronine (T3) and 3,3'5'-triiodothyronine (reverse T3) in 10 massively obese women were studied before and at intervals for one year after jejuno-ileal bypass operation. A significant rise in T3 (P less than 0.01) over the immediately preoperative value, a significant fall in rT3 (P less than 0.01) but no significant change in T4 was found during the post-recovery follow-up period. It is concluded that maintaining a relatively high T3 level following jejuno-ileal bypass surgery may contribute to the substantial weight reduction achieved by patients after this operation.