THE EFFECT OF RECOMBINANT HUMAN GROWTH-HORMONE ON GLUCOSE AND LEUCINEMETABOLISM IN CUSHINGS-SYNDROME

Gushing's syndrome is characterized by central obesity and muscle wast ing. As GH is anabolic, it may be able to counteract the loss of body protein. To evaluate the potential therapeutic use of GH preoperativel y, eight patients with Gushing's syndrome received sc injections of re combinant human GH (0.07 U/kg . day) for 7 days. Whole body leucine an d glucose turnover were measured after an infusion of [1-C-13]leucine and [6,6-H-2(2)]glucose before (day 0) and after 2 and 7 days of GH tr eatment. Compared with the value on day 0, there was a significant inc rease on days 2 and 7 in insulin (P < 0.005 and P < 0.001), C peptide (P < 0.01 and P < 0.005), insulin-like growth factor I (P < 0.001), an d glucose concentrations (P < 0.01 and P < 0.005) and decrease in the leucine concentration (P < 0.005). There was no significant change in glucose production rate, glucose MCR, leucine production rate (a measu re of protein degradation), or nonoxidative leucine disappearance rate (a measure of protein synthesis). The leucine MCR was increased after 7 days (P < 0.05), and the clearance of leucine into protein (nonoxid ative leucine disappearance rate/leucine concentration) was increased (P < 0.05) after 2 and 7 days of GH treatment. This is consistent with GH stimulating the availability of aminoacid transporters. GH may, th erefore, have a therapeutic role in the preoperative treatment of Gush ing's syndrome.