Demonstration of two forms of vitellogenin in serum of estradiol-17 beta-treated Indian major carp, Labeo rohita.

ABSTRACT

Vitellogenin (Vg) synthesis was induced in the male and non-vitellogenic female Rohu, the Indian major carp, by estradiol-17 beta(E2) where effect was more in female. A crude preparation of Vg was isolated in the second peak after gel filtration on Ultrogel AcA 34 from the sera of vitellogenic female Rohu and E2-treated male and female Rohu. Estimation of alkali-labile phosphorus was shown to be used as an index of Vg. Native-PAGE analysis has revealed the presence of two forms of Vg (Vg1 430,000 dalton and Vg2240,000 dalton) in Vg fraction obtained after gel filtration as well as in the sera of E2-treated male and female Rohu. Immunological cross-reaction studies between antiserum to yolk protein and Vg fractions as well as the sera from E2-treated male and female Rohu further indicates the presence of two precipitin lines (not clearly visible as the two lines fused to form a thick line) suggesting the occurrence of two forms of Vg in the Rohu.