ENDOCRINE CONTROL OF THE LIPID METABOLISM OF THE BIRD. IV. LIPID METABOLISM OF THE BIRD DURING PUBESCENCE AND THE ANNUAL REST1

Abstract

The lipid metabolism of the bird was investigated during periods of its life when the most rapid changes in ovarian activity are occurring: pubescence, and approach of the annual rest, the rest itself and emergence from it. The blood lipid level of pubescent birds increased abruptly about the time the oviduct attained a wt. of 15 to 18 g. No close relation existed between the onset of yellow yolk deposition in the developing ovum and the blood lipid level. Fatty livers occurred in the pubescent bird. Increases in the lipid content of the liver may precede increases in the lipid levels of the blood. Elevated lipid levels were usually present in the bird until the onset of the annual rest, at which time the blood lipids returned to values approx. those found in the immature state. Increased lipid levels were again present in the blood of birds emerging from rest.