Comparison of the effect of hypothalamic neuropeptides upon luteinizing hormone secretion by cultured rat anterior pituitary cells

L. A. Leiva, H. B. Croxatto

Producción científica: Contribución a una revistaArtículorevisión exhaustiva

25 Citas (Scopus)


Bovine median eminence contains a factor different from gonadotropin- releasing hormone (GnRH) that increases basal luteinizing hormone (LH) secretion and potentiates GnRH-stimulated LH release. We compared the effects of hypothalamic neuropeptides on basal and GnRH-stimulated LH secretion using rat pituitary cells under static incubation conditions to determine if any of them mimics the LH-releasing activity not attributable to GnRH present in bovine median eminence extracts. Both, galanin and neurotensin (10 -9-10 - 5 M) stimulated basal LH secretion in a dose-response manner. Galanin increased 3-4 fold and neurotensin doubled the basal LH secretion. The GnRH antagonist Nal-Glu 10 -6 M abolished the effect of 10 -7 M GnRH and 10 -5 M neurotensin, but did not block the LH-releasing activity of galanin. Leucine-enkephalin, β-endorphin, substance P and neuropeptide Y (NPY) did not alter basal LH secretion. Neuropeptides produced three types of response on GnRH-stimulated LH release. First, leucine-enkephalin and β-endorphin (10 -9-10 -5 M) showed a dose-dependent inhibition of GnRH-stimulated LH release. At 10 -5 M the inhibition was complete with leucine-enkephalin and only 30% with β-endorphin. Both were blocked by naloxone. Second, substance P showed an inverted U type response on GnRH-stimulated LH secretion. At 10 - 9 M this peptide potentiated the action of GnRH. This effect decreased when the dose of substance P was increased to 10 -7 M and turned inhibitory at 10 -5 M when 10 -7 M GnRH was used. Third, galanin and NPY potentiated the effect of GnRH on LH secretion. Neurotensin had no effect on GnRH-stimulated LH release. In conclusion, rat gonadotrophs present diverse responses to neuropeptides at physiological concentrations, and -apart from GnRH- galanin is most likely the other factor present in bovine median eminence extracts that stimulates LH secretion. The data lend further support to a role of galanin in the control of LH secretion.

Idioma originalInglés
Páginas (desde-hasta)113-121
Número de páginas9
PublicaciónBiological Research
EstadoPublicada - 1994

Áreas temáticas de ASJC Scopus

  • Ciencias Agrícolas y Biológicas General


Profundice en los temas de investigación de 'Comparison of the effect of hypothalamic neuropeptides upon luteinizing hormone secretion by cultured rat anterior pituitary cells'. En conjunto forman una huella única.

Citar esto