Forearm Metabolism In Obesity And Its Response To Intra-arterial Insulin. Characterization Of Insulin Resistance And Evidence For Adaptive Hyperinsulinism.

Obesity is considered ordinarily to be a consequence of overeating by an otherwise normal person, but the notion persists that there may be some underlying metabolic defect. The man of 70 kg, on becoming 20 per cent overweight, doubles his adipose organ mass (3). If obesity is viewed as a state of chronic substrate excess necessitating increase in fat storage of this magnitude, one might indeed predict that certain metabolic adjustments would occur, resulting in alterations in, but not implying a primary disturbance of, intermediary metabolism. Metabolism of obese subjects has been examined by measuring metabolic events in the forearm, which is predominantly skeletal muscle and adipose tissue, in the search for answers to the following questions. 1) What departures from normal take place in basal forearm metabolism of obese subjects and what light do these differences shed on adaptation to chronic substrate excess? 2) Is "simple" obesity related to maturity onset diabetes mellitus, in which obesity is common? Because resistance to exogenous insulin occurs in untreated maturity onset diabetes (4), response to intra-arterial -insulin was examined in simple obesity. From the observations it became clear that there are a number of similarities in metabo-