The Prader-Willi syndrome. Regulation of fat transport

Studies of fat mobilization and transport are reported in six patients with the Prader-Willi syndrome. Two patients had carbohydrate intolerance. One of these had a low and the other an augmented insulin response to glucose challenge. Following challenge with glucose, three of the four nondiabetics had normal insulin responses or increased responses consistent with their obesity; the other nondiabetic had insulinopenia. Measurements of the effects of norepinephrine, insulin, glucose, and 5-methylpyrazole-3-carboxylic acid on plasma levels of FFA, glycerol, and ketones provide no evidence for abnormal regulation of mobilization of fat from adipose tissue. Measurements of plasma lipids and postheparin lipolytic activity are consistent with normal uptake of fat into adipose tissue, and normal fatty acid composition of adipose tissue gives no evidence for abnormal lipogenesis.