In Vivo and in Vitro Actions of Low-Molecular-Weight Gonadal Peptides

Abstract

Two low-molecular-weight gonadal peptides, IRRP3 and IRRPS, have been isolated from sheep ovaries having different biological properties in male rats. The peptide IRRP3 has specific effect on (1) FSH secretion as well as release at the pituitary level, (2) in vitro binding of labeled FSH to testicular receptor, and (3) in vivo uptake of labeled FSH by the testis, whereas peptide IRRPS has specific effect on (1) LH secretion at the pituitary level, (2) in vitro binding of labeled LH to testicular receptor, and (3) in vivo uptake of labeled LH by the testis.

Identification of luteinizing hormone receptor binding inhibitor in bovine corpora lutea

“…The LH-RBI activity was present in a heat-stable low-molecular-weight protein fraction of an approximate molecular weight of 3800 D, as well as in a heat-labile high-molecularweight protein fraction (1). The presence of LH-RBI activity in the luteal tissue of porcine ovaries as well as in the corpora lutea of pregnant cat, dog, sheep and goat was identified subsequently (2)(3)(4)(5). Kumari et al.…”