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Biomedical subjects

H Papkoff

Publications and source records attributed to H Papkoff.

At least 91 records · Page 5Linked to original sources
PubMed1978

Pregnant mare serum gonadotrophin and follicle-stimulating hormone stimulation of cyclic AMP production in rat seminiferous tubule cells.

Pregnant mare serum gonadotrophin (PMSG) was found to stimulate the production of cyclic AMP in isolated rat seminiferous tubule cells. The PMSG was equipotent with highly purified ovine FSH. The subunits of PMSG were inactive in this system but recombination resulted in partial restoration of activity, and the combination of PMSG alpha-subunit with FSH beta-subunit was even more active. Desialation of PMSG, but not of ovine FSH, resulted in a reduction of slope and potency of this response, suggesting that sialic acid may be important for the interaction of PMSG and the Sertoli cell. Further tests of the responsiveness of this cell preparation demonstrated activity with several species of mammalian FSH molecules, but not with FSH molecules obtained from non-mammalian species.

Animals↗
PubMed1977

Biological activity of bullfrog growth hormone in the rat and the bullfrog (Rana catesbeiana).

Highly purified bullfrog growth hormone (GH) was tested for growth promoting activity in rats and bullfrogs (Rana catesbeiana). In repeated assays, the potency of bullfrog GH in the rat tibia assay was 1 X bovine GH, which is significantly greater than all other non-mammalian GHs tested. It also stimulated significant whole body growth in immature hypophysectomized rats injected daily for 16 days. In bullfrogs, the bullfrog GH (about 2 microgram/injection) stimulated growth and appetite in intact frogs, and improved survival in hypophysectomized frogs. In contrast, even relatively high doses of bovine GH (up to 200 microgram/injection) were inactive in the bullfrog.

Animals↗