Sites of Formation of Plasma Phosphoprotein and Phospholipid in the Estrogenized Cockerel

Abstract

Estrogen increased plasma Ca, but not plasma total protein, phosphoprotein P, or phospholipid P, in functionally hepatectomized cockerels. Estrogen increased all four plasma constituents in sham-operated cockerels. Functional hepatectomy of the estrogenized cockerel abolished incorporation into plasma phosphoprotein of injected orthophosphate labelled with P32, and reduced but did not abolish incorporation of P32 into plasma phospholipid. These observations are submitted as direct evidence that plasma phosphoprotein in the estrogenized cockerel is exclusively hepatic in origin.

Calcium Metabolism and Avian Reproduction

“…Although the concept that the hypercalcaemia of birds is related to yolk proteins is a fruitful one, it has been criticized. It is known that the liver is responsible for the formation of most of the phosphatides and yolk proteins, which are carried by the plasma to the ovary (Hahn & Hevesy, 1937), and Vanstone, Dale, Oliver & Common (1957) operated upon the fowl so that by later tightening ligatures they were able functionally to hepatectomize them. When the ligatures were tightened the formation of vitellin protein was completely inhibited, but there was no fall in the high serum calcium level.…”

High Estrogen Production of the Medium-Sized Follicles during Follicular Growth and Ovulation in the Laying Quail

“…Of these steroids, estrogen seems to play a prominent role in vitellogenesis. Its presence in the yellow follicles was first reported in 1940 (Marlow and Richaert, 1940) and its stimulating action on the synthesis of immediate precursors of egg yolk by the liver (Hosoda, 1952;Vanstone et al, 1957) are well established. It had long been suspected intuitively that in the disposition the larger the follicle the higher the secretion of estrogen, but no attempt has ever been made to elucidate the maturation process of the follicle through the analysis of their estrogen production.…”