EFFECT OF AVIAN PITUITARY PREPARATIONS ON THE PLASMA FREE FATTY ACIDS OF THE RABBIT AND THE DOMESTIC FOWL.

Abstract

PREVIOUS experiments1 have shown that the levels of plasma free fatty acids in the domestic fowl, which are markedly elevated in laying birds2, were also increased in immature pullets by treatment with œstrogens. They were not altered by the injection of crude extracts of pig anterior pituitary, though these extracts were effective in increasing the levels of plasma free fatty acids in the rabbit. Since this difference could be attributed to the difference in responsiveness of the two species to a hormone derived from a third species, it was not possible to decide whether or not the increased levels of plasma free fatty acids, normally found in the laying bird, were directly due to the secretion of pituitary hormones or to some other cause. Experiments to investigate this point have now been performed with preparations of avian pituitary powder. Pituitaries from broiler hens were dehydrated and powdered by dispersing in acetone in a high-speed macerator. The whole pituitary was used since the object of the experiment was to determine whether there was a pituitary factor, present in either lobe, capable of increasing the plasma free fatty acids in the bird. The results of experiments in which suspensions of the whole powder, in saline, were administered to birds and to rabbits are presented in Table 1. It is clear that avian pituitary powder, though effective in increasing the levels of plasma free fatty acids in the rabbit, had little effect in the domestic fowl.