Effects of hypothalamic lesions on levels of plasma free fatty acids in the mallard duck.

Plasma free fatty acid (FFA) levels were measured in the mallard duck (Anas platyrhynchos) following hypothalamic lesions at various sites. The results indicate that ventromedial lesions produced hyperphagia, increased deposition of fat, and significantly elevated levels of plasma FFA. Anterior bilateral lesions resulted in aphagia, severe loss in body weight and a marked decrease in plasma FFA. Lesions in other regions of the hypothalamus produced various changes depending upon the extent of damage. The neural and neuroendocrine mechanisms which regulate FFA levels in the blood are discussed with respect to the involvement of pituitary hormones.