A 14-Kilodalton Prolactin-Like Fragment Is Secreted by the Hypothalamo-Neurohypophyseal System of the Rat
Por:
Torner L., Mejía S., López-Gómez F.J., Quintanar A., Martínez de la Escalera G., Clapp C.
Publicada:
1 ene 1995
Resumen:
The recently described expression of the PRL gene, and the occurrence of a 14-kilodalton (kDa) PRL-like immunoreactive protein in the hypothalamo-neurohypophyseal system of the rat have raised the possibility that PRL variants are released from neurohypophyseal terminals into the blood. In this study, we investigated the local production of a hypothalamo-neurohypophyseal 14-kDa PRL-like protein by showing an independent origin from adenohypophyseal PRL. No 14-kDa PRL-like protein was detected in adenohypophyseal extracts by Western blots, whereas chronic hypophysectomy produced no change in the immunocytochemical detection of PRLs in supraoptic and paraventricular magnocellular neurons. In addition, a 14-kDa immunoreactive PRL-like protein was released into the medium by incubated neurohypophyseal lobes. Western blot analysis showed that significantly more of this 14-kDa protein was released into calcium-containing medium (1.8 mM) than into calcium-free medium. Furthermore, depolarizing concentrations of potassium (56 mM) increased by 3-fold the release of immunoreactive PRL by incubated hypothalamo-neurohypophyseal explants. In addition, a 14-kDa PRL-like antigen was detected in the circulation of the rat by Western blot analysis. These results are consistent with the local synthesis and calcium-dependent release of neurohypophyseal PRL-like proteins that include a predominant 14-kDa form.
Filiaciones:
Torner L.:
Centro de Neurobiología, Uniuersidad National Autónoma de México, México D.F, 04510, Mexico
Mejía S.:
Centro de Neurobiología, Uniuersidad National Autónoma de México, México D.F, 04510, Mexico
López-Gómez F.J.:
Centro de Neurobiología, Uniuersidad National Autónoma de México, México D.F, 04510, Mexico
Quintanar A.:
Centro de Neurobiología, Uniuersidad National Autónoma de México, México D.F, 04510, Mexico
Centro Básico, Universidad Autónoma de Aguascalientes, Aguascalientes, 20100, Mexico
Clapp C.:
Centro de Neurobiología, Uniuersidad National Autónoma de México, México D.F, 04510, Mexico
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