Thyrotropin-releasing hormone and gonadotropin-releasing hormone-associated peptide modulation of [Ca2+]i in human lactotrophs.
Mol Cell Endocrinol
; 95(1-2): 67-74, 1993 Sep.
Article
en En
| MEDLINE
| ID: mdl-8243809
ABSTRACT
The effect of thyrotropin-releasing hormone (TRH) and gonadotropin-releasing hormone-associated peptide (GAP) was studied on both secretion and intracellular free Ca2+ concentrations ([Ca2+]i) in human pituitary cells cultured from prolactin (PRL)-secreting tumors. Secretion was measured during a 30-min incubation period and we used a microspectrofluorimetric method in individual cells and indo-1 as the fluorescent probe. TRH (10(-8) M) significantly increased PRL release in five out of the six cell populations. In these five cases, more than 68% of individual cells responded to TRH by an increase in [Ca2+]i. No significant increase in PRL secretion was found in another culture in which TRH increased [Ca2+]i in only 37% of the cells. The effect of GAP (10(-7) M) was studied in five cell populations. In three of them, a decrease of 20% to 51% of the PRL basal secretory rate was observed under GAP. GAP inhibited [Ca2+]i in respectively 59%, 46% and 94% of the cells from these cultures. The inhibitory effect of GAP was blocked by a pertussis toxin (PT) pretreatment which demonstrates the involvement of a PT-sensitive G-protein in GAP action. In two other cultures, GAP did not significantly alter PRL secretion or individual cell [Ca2+]i. These observations suggest that GAP might play a role in the control of PRL secretion in the human.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Adenohipófisis
/
Neoplasias Hipofisarias
/
Prolactina
/
Precursores de Proteínas
/
Prolactinoma
/
Calcio
/
Hormona Liberadora de Gonadotropina
/
Hormona Liberadora de Tirotropina
Tipo de estudio:
Risk_factors_studies
Límite:
Adolescent
/
Adult
/
Female
/
Humans
/
Male
/
Middle aged
Idioma:
En
Revista:
Mol Cell Endocrinol
Año:
1993
Tipo del documento:
Article
País de afiliación:
Francia