Pregnant Mare Serum Gonadotrophin: Ratio of Follicle-Stimulating Hormone and Luteinizing Hormone Activities Measured by Radioreceptor Assay

Abstract

Specific radioreceptor assays for FSH and LH, which employ tissue receptors from rat testis and highly purified human FSH (LER 1575-C) and LH (Hartree IRC-2, 24/6/69) as standards, have been developed to determine the FSH-like and LH-like activities in pregnant mare serum gonadotropin (PMSG). Measurements of FSH and LH concentrations in the serum of six pregnant Pony mares showed that the ratio of these two activities did not vary significantly between mares and remained constant between days 40 and 80 of gestation with a value of 1-45 +/- 0-04 (S.E.M.). The FSH:LH ratio of PMSG produced by cultured equine trophoblast cells was found to be 0-72 +/- 0-03 (S.E.M.) and that of partially purified serum extracts of PMSG 1-08 (range 0-87-1-30).

Influence of dose, repeated treatment and batch of hormone on ovarian response in heifers treated with PMSG

“…The finding of non-significant differences in FSH : LH ratio between batches supports the finding of Stewart et al (1976) and Schams et al (1978) and also the suggestion that it is unlikely that the variation in response which occurs between animals treated with PMSG is due to differences in the FSH :LH ratio of the PMSG preparations used (Stewart etal, 1976).…”

“…The FSH-like and LH-like activities of the 3 batches were measured by rat testicular radioreceptor assays using highly purified human pituitary FSH and LH preparations as radiotracers and as standards (Stewart et al, 1976). Each batch of PMSG had been stored at -20°C until used or assayed and each dose of PMSG for injection into animals was reconstituted in 10 ml physio¬ logical saline (9 g NaCl/1) immediately before injection into the gluteal region.…”

“…The results in Table 2 show that the higher dose of PMSG gave a substantially increased response in the number of ovulations and follicles, but there was no clear evidence of a dose effect in the proportion of follicles present in the ovaries. (Stewart et al, 1976). Surprisingly, the error variance between animals was not significantly greater than the variation within animals, perhaps reflecting the erratic response of the animals in the two treatments.…”

“…PMSG has FSH and LH biological activities (Cole, 1936;Bangham & Woodward, 1966;Gospodarowicz, 1972) and this has led to the suggestion that the ratio of these components in different batches of PMSG may affect ovarian response (Lamond, 1970). Stewart, Allen & Moor (1976), using rat testis radioreceptor assays to measure FSH and LH activity, found no significant difference in the FSH:LH ratios of 6 batches of commercially available PMSG (Folligon: Intervet Laboratories, UK). Schams et al (1978), using similar radioreceptor assay methods, found similar FSH:LH ratios in 3 other batches of PMSG (Intervet Int.…”

Avaliação hormonal sérica e estereológica da membrana corioalantóide a termo de éguas: influência no desenvolvimento e nos parâmetros clínicos e metabólicos do potro

“…Trata-se de um hormônio glicoproteico de alto peso molecular secretado pelas células do cálice endometrial, que expressa aproximadamente em igual proporção hormônios com atividade biológica tipo FSH e LH (STEWART; ALLEN; MOOR, 1976;ALLEN et al, 2002b).…”