In vivo and in vitro metabolism in hypothalamic obesity

Summary U-¹⁴C-Glucose was injected into weanling rats two weeks after electrolytic destruction of the ventromedial hypothalamic nuclei. Incorporation of radio-activity into plasma lipids as well as liver, adipose tissue, diaphragm and carcass glycogen, total lipid and saponifiable fatty acids was measured. On a fat free as well as on a chow diet, rats with lesions incorporated more radioativity into all adipose tissue components and into liver fatty acids but not into liver glycogen. On the fat containing diet (chow) radioactivity of plasma lipid was increased and that of liver total lipid unchanged, whereas on a fat-free diet incorporation into plasma lipid was not increased while that into liver lipid was. Diaphragm total lipid and fatty acid radioactivity was increased while that of diaphragm glycogen was not. Carcass lipid, fatty acid and glycogen radioactivity were increased. — Diaphragm was also incubatedin vitro with U-¹⁴C-Glucose or 1-¹⁴C-Palmitate. Glucose incorporation into total lipid and fatty acid was increased whereas oxidation and incorporation into glycogen were not. Palmitate oxidation and incorporation into phospholipid were decreased while incorporation into triglyceride was increased. - Results have been discussed in the light of similar changes previously noted with adipose tissuein vitro.This work was supported by USPHS Grants AM 11746, AM 14418, American Heart Association and Mid-Hudson Heart Association Grants and a V. A. Clinical Investigatorship and Research Grant 01/3193-1/69-01 (J.K.G.).