PLASMA-LEVELS OF VITELLOGENIN IN CHRYSEMYS-PICTA DURING THE ANNUAL GONADAL CYCLE - MEASUREMENT BY SPECIFIC RADIOIMMUNOASSAY

A RIA for turtle (Chrysemys picta) vitellogenin is described. After dimethylformamide precipitation of vitellogenin from the plasma of estrogen-treated female turtles, antibodies were developed in rabbits. The dimethylformamide precipitate was further purified by o-triethylaminoethyl cellulose column chromatography; the vitellogenin component eluted as a single peak. This material was used for iodination by a mild chloramine method. Antibodies to turtle vitellogenin did not cross-react with plasma from male turtles or vitellogenic females of other vertebrate groups, including lizards and snakes. Limited cross-reactivity exists among the chelonians, however. Using a 1:5000 dilution of antiserum, the limit of detection was 15 ng, and the midrange was 320 ± 45 ng. For an antiserum dilution of 1:1000, these figures were 30 and 600 ± 37 ng, respectively. Using this assay, the seasonal pattern of plasma vitellogenin in the turtle has been described, and preliminary studies on in vitro hepatic vitellogenesis have been performed. © 1979 by The Endocrine Society.