Vitellogenesis in the lizard Lacerta vivipara jacquin. I. Purification and partial characterization of plasma vitellogenin.

The polypeptide moiety of lizard plasma vitellogenin was reproducibly dissociated and separated by SDS-PAGE into two subunits: Vg alpha 2-2.2 X 10(5) Da and Vg beta 1-1.1 X 10(5) Da. In estrogenized females, active incorporation of inorganic 32P into both vitellogenin chains present in the plasma, and in the culture medium of the liver, was identified following autoradiography of SDS-polyacrylamide gels. Lacerta vivipara vitellogenin was isolated from pooled plasma collected from heavily estrogenized males by the two-step precipitation procedure of H. S. Wiley, L. Opresko, and R. A. Wallace, (1980, Anal. Biochem. 97, 145-152), followed by chromatography on DEAE-cellulose. This preparation of L. vivipara vitellogenin was of sufficient purity to generate in rabbits an immune serum which cross-reacted very slightly with plasma free of vitellogenin (rocket immunoelectrophoresis). Using the double immunodiffusion procedure it was shown that the anti-vitellogenin serum recognized identical antigenic determinants in plasma from a vitellogenic female or from estrogenized lizards, and in crude vitellus. The immunodetection of L. vivipara native vitellogenin consistently allowed two circulating forms to be distinguished. After autoradiography of a rocket immunoelectrophoresis plate it was demonstrated that both native forms had incorporated inorganic 32P into the polypeptide moiety and/or the phospholipid moiety.