The effect of vertical banded gastroplasty on glucose-induced beta-endorphin response

Background. beta-Endorphin is an endogenous opioid involved in the regulati on of food intake and obesity as well as in insulin metabolism, In this stu dy, we investigated glucose-induced beta-endorphin, insulin, and glucose re sponsiveness in morbidly obese patients and the effect of surgically induce d weight loss, Methods. Thirty-two healthy, nondiabetic, morbidly obese patients (body mas s index over 40 kg/m(2)) and 32 normal-weight controls were studied. Serum levels of P-endorphin, insulin, and glucose were measured under basal condi tions and during an oral glucose tolerance test (OGTT) before and 12 months following vertical banded gastroplasty. Results. Preoperative basal levels of beta-endorphin, insulin, and glucose and their responses during OGTT in obese patients were significantly higher compared with those of controls. After surgery, basal beta-endorphin, insu lin, and glucose levels decreased significantly compared with preoperative values. Postoperative basal insulin and glucose levels were similar to thos e in controls, while beta-endorphin levels remained significantly higher th an those of controls. A significant reduction in total responses of beta-en dorphin, insulin, and glucose during OGTT was also observed; however, posto perative beta-endorphin and insulin responses remained significantly higher than in controls. Conclusion. Morbidly obese patients have an increased glucose-stimulated re sponse of beta-endorphin, insulin, and glucose which is partially corrected with weight loss following vertical banded gastroplasty. (C) 1998 Academic Press.