The mobilization of free fatty acids from rabbit adipose tissue in situ.

1. The epigastric adipose tissue of rabbits has been prepared so that the effects of close arterial injections and infusions on blood flow and release of free fatty acids (FFA) can be studied. The effects of pharmacologically active agents and hormone preparations have been investigated.2. Release of FFA was stimulated by synthetic adrenocorticotrophic hormone (ACTH), alpha and beta melanophore stimulating hormone (MSH), porcine growth hormone, glucagon, thyrotropic hormone (TSH) and luteotropic hormone (LTH). Single injections of fat-mobilizing agents produce a sustained rise in the release of FFA.3. Although pitressin caused release of FFA, synthetic vasopressin and oxytocin failed to do so. The FFA releasing activity of pitressin has therefore been attributed to a contaminant.4. Catecholamines were found not to stimulate release of FFA from this fat depot, but were found to increase plasma FFA when infused intravenously.5. Injections of acetylcholine, histamine, bradykinin, 5-hydroxytryptamine, synthetic arginine vasopressin, and lysine vasopressin, oxytocin, angiotensin and FSH did not stimulate release of FFA although marked effects on blood flow were produced.6. Injections of prostaglandin E(1) gave sustained increases in blood flow, and inhibited FFA release when stimulated by growth hormone.7. The mobilization of FFA is sometimes associated with an increased rate of blood flow.