Lipoatrophy produced in mice and rabbits by a fraction prepared from the urine from patients with congenital generalized lipodystrophy.

Urine from 5 patients with congenital generalized lipodystrophy has been fractionated by protein precipitation and Sephadex gel filtration. A fraction with a molecular weight in the range of 1000 was observed to be metabolically active in mice, rats, and rabbits. Hypophysectomized rats got hypoglycaemia following an injection, and the lipolytic-hyperglycaemic effect of ACTH was reduced after injection into intact mice. This effect was probably due to insulin release, because no insulin-like activity was observed on isolated fat cells in vitro. Persistant changes were observed in the animals after 3 weeks of daily injections of the urinary fraction. Adult mice and rabbits developed lipoatrophy with decrease of body weight in spite of a doubling of the food consumption. The metabolic rate and the body temperature were raised. Infantile animals developed a lipodystrophic state with increased growth velocity, and 50 per cent increase of the body weight, although no fat depots were observed. The treated animals got hyperglycaemia, hypertriglyceridaemia, hyperinsulinaemia, and insulin resistance. The rabbits developed manifest diabetes. The corresponding fraction prepared from the urine from the lipoatrophic rabbits produced lipoatrophy after injection into the mice. It is suggested that the lipodystrophic urinary fraction is of hypothalamic origin, and that it acts through the pituitary gland. The fraction is still heterogenous, and was observed to contain thyrotrophin releasing activity.