Amino acid sequence of a major apoprotein from hen plasma very low density lipoproteins.

In nonlaying hens or in cockerels, the administration of estrogen dramatically increases the level of plasma triglycerides (1, 2). Luskey et al. (3) have shown that one effect of estrogen was to increase the rate of synthesis of the very low density lipoproteins (VLDIJ’ proteins. The mechanism for this induction is presumably through an increase in mRNA for the yolk proteins (4-6). In a recent report (71, a small molecular weight apoprotein from hen VLDL was isolated and its synthesis studied in an in vitro system using a partially purified mFtNA extracted from livers of estrogen-treated cockerels. In this study, it was suggested that estrogen regulates the mRNA activity for this apoprotein. As a prerequisite to further studies on the regulation of VLDL synthesis in the hen, we now report the complete amino acid sequence of this apoprotein, designated hen apoVLDL-II.