title: [Hypothalamic inhibiting factor of luteinizing hormone secretion: relation to the fragment 1-5 of the LH releasing hormone].
abstract: In this paper we review the mechanisms underlying the control of gonadotrophin (Gn) release and present evidences of the existence of a luteinizing hormone release-inhibitory factor. We have extracted and partially characterized this factor from rat hypothalamus and bovine median eminence. Our data indicate that the factor is a peptide that has a common antigenic determinant with GnRH, but is of smaller molecular weight than GnRH (750 daltons approximately). These facts strongly suggest that it may be a fragment of the GnRH molecule. The synthetic fragment GnRH (1-5) has similar biologic effects and molecular weight to those of the inhibitory factor obtained from the median eminence and hypothalamus. GnRH (1-5) has been shown to be produced in vitro by cleavage of GnRH by an hypothalamic endopeptidase. Based on this evidences, we suggest that the inhibitory peptide found by us is formed in vivo by degradation of GnRH. Moreover, we suggest that this factor may play a role on the regulation of LH release induced by GnRH.
authors.affiliation: Departamento de Ciencias Fisiológicas, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago.
authors.forename: M
authors.initials: M
authors.lastname: de la Lastra
authors.forename: J
authors.initials: J
authors.lastname: Leal
mesh_terms: D000818:Animals; D002417:Cattle; D010450:Endopeptidases / Q000378:metabolism*; D005260:Female; D005640:Follicle Stimulating Hormone / Q000378:metabolism; D007987:Gonadotropin-Releasing Hormone / Q000037:antagonists & inhibitors*; D007030:Hypothalamo-Hypophyseal System / Q000502:physiology*; D007986:Luteinizing Hormone / Q000378:metabolism; D010906:Pituitary Hormone-Releasing Hormones / Q000494:pharmacology*; D051381:Rats
chemical_list: D010906:Pituitary Hormone-Releasing Hormones; D007987:Gonadotropin-Releasing Hormone; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone; D010450:Endopeptidases
vernacular_title: Factor hipotalámico inhibidor de la secreción de hormona luteinizante: relación con fragmento 1-5 de hormona liberadora de LH.