Studies on two types of gonadotropins from both salmon and carp pituitaries

Abstract

Two molecular weight forms of salmon vitellogenic Con AI (unadsorbed on concanavalin A-Sepharose) hormone and the salmon maturational Con AII (adsorbed on concanavalin A-Sepharose) hormone were able to stimulate vitellogenesis in the female winter flounder ( Pseudopleuronectes americanus). Both the salmon vitellogenic Con AI 45,000-dalton hormone and the maturational Con AII hormone were able to enhance in vivo phosphate and leucine uptake by the flounder testis and incorporation into testicular proteins. Only the salmon maturational Con AII hormone was able to evoke spermiation and ovulation and it was much more potent than the vitellogenic Con AI hormones in stimulating testicular steroidogenesis. The vitellogenic and maturational activities of the salmon Con AII gonadotropin were partially destroyed on desialylation while the vitellogenic activity of the Con AI gonadotropins was not affected. The immunologic activity of the maturational Con AII hormone was retained after desialylation, but was abolished upon carboxamidomethylation. The immunologic potencies of the vitellogenic Con AI hormones were preserved after desialylation. The two salmon vitellogenic Con AI hormones displayed numerous prominent differences in amino acid and carbohydrate compositions from, and were immunologically remote from, the salmon maturational Con AII hormone. There was a marked dissimilarity in amino acid composition between the immunologically distinct salmon vitellogenic Con AI hormones. Two gonadotropins (vitellogenic Con AI and maturational Con AII), with an identical molecular weight of 30,000 daltons, were prepared from the pituitaries of the carp Cyprinus carpio. The distribution of biological activities was in general similar to that observed between the salmon hormone. The carp vitellogenic Con AI hormone could also be distinguished from the maturational Con AII hormone in the composition of its protein and carbohydrate moieties.