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Fractionation and Biological Actions of Pituitary Gonadotropins from a Marsupial, the Wallaby (Macropus eugenhl)1

1978; Oxford University Press; Volume: 19; Issue: 3 Linguagem: Inglês

10.1095/biolreprod19.3.680

1529-7268

Antonella Bona Gallo, Paul Licht, Susan Walker Farmer, Harold Papkoff, J.C. Hawkins,

Growth Hormone and Insulin-like Growth Factors

Fractionation of pituitaries from a macropod marsupial, the wallaby (Macropus eugenii), yielded two distinct types of gonadotropins whose biological profiles, chromatographic behavior and amino acid composition resembled the follicle stimulating hormone (FSH) and luteinizing hormone (LH) of eutherian species. Also, the wallaby LH showed complete immunological cross reactivity in a homologous radioimmunoassay for ovine LH, while only wallaby FSH crossreacted in a heterologous radioimmunoassay based on anti-ovine FSH and 125I-labeled human or rat FSH. The purified wallaby FSH was relatively potent in Steelman-Pohley bioassay (ca. 10–20 units NIH-FSH-S1/mg), while the wallaby LH showed little activity (<1.2 units/mg.) Wallaby LH stimulated testosterone production by rat Leydig cells, but it was only about 1% as active as ovine LH. In contrast, wallaby LH was essentially equipotent with ovine LH in stimulating in vitro androgen production by minced testis of a marsupial, the opossum (Didelphis virginiana); stimulation of testicular androgen production in the opossum was also highly specific for LH. In turtle testes, wallaby gonadotropins behaved like those of eutherians; wallaby and ovine FSH were more potent than LH in stimulating androgen production. Wallaby FSH and LH were relatively active in competitive binding assays employing 125I-labeled human FSH and hCG, respectively, with gonads from several eutherian and metatherian mammals. The distinctiveness of FSH and LH binding sites was demonstrated in the marsupial testes using ovine hormones, but wallaby LH had a high FSH-like activity (22–28% of wallaby FSH) in all competitive binding assays. This activity of wallaby LH was greater than expected from radioimmunological estimates of its FSH contamination (about 3%).