Metabolic effects of weight loss in obese subjects. Changes in plasma substrate levels, insulin and growth hormone responses

Oral glucose tolerance and intravenous tolbutamide, glucagon and insulin tolerance were assessed in six obese patients before and after an average weight loss of eighty-five pounds and a reduction from 83 to 27 per cent above ideal body weight. Results were compared to ten nonobese subjects of similar age.

Before treatment fasting plasma glucose, free fatty acids and immunoreactive insulin exceeded normal levels. Total plasma alpha-amino acid nitrogen levels were unaffected by obesity. Post-challenge insulin responses during the first three tolerance tests were two to four-fold above control responses, and increments of immunoreactive growth hormone during insulin tolerance were subnormal in the obese. After weight reduction only minor differences in mean yjilues existed between obese and control groups.

These findings indicate that disturbances in fasting plasma substrate levels as well as plasma insulin and growth hormone responses fii obese individuals are reversible after substantial weight reduction.