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Titolo:
GROWTH-HORMONE (GH)-RELEASING PEPTIDE AND GH RELEASING HORMONE STIMULATE GH RELEASE FROM SUBPOPULATIONS OF SOMATOTROPHS IN RATS
Autore:
MITANI M; KAJI H; ABE H; CHIHARA K;
Indirizzi:
KOBE UNIV,SCH MED,DEPT MED,DIV 3,CHUO KU,7-5-1 KUSUNOKI CHO KOBE 650 JAPAN KOBE UNIV,SCH MED,DEPT MED,DIV 3,CHUO KU KOBE 650 JAPAN
Titolo Testata:
Journal of neuroendocrinology
fascicolo: 11, volume: 8, anno: 1996,
pagine: 825 - 830
SICI:
0953-8194(1996)8:11<825:G(PAGR>2.0.ZU;2-W
Fonte:
ISI
Lingua:
ENG
Soggetto:
PITUITARY-CELLS; SYNTHETIC HEXAPEPTIDE; INVIVO ACTIVITY; NORMAL MEN; FACTOR-I; HIS-D-TRP-ALA-TRP-D-PHE-LYS-NH2; INVITRO; MECHANISMS; SECRETION; CULTURE;
Keywords:
GROWTH HORMONE RELEASING PEPTIDE; GROWTH HORMONE RELEASING HORMONE; SOMATOTROPH; REVERSE PLAQUE HEMOLYTIC ASSAY; GROWTH HORMONE;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Science Citation Index Expanded
Citazioni:
31
Recensione:
Indirizzi per estratti:
Citazione:
M. Mitani et al., "GROWTH-HORMONE (GH)-RELEASING PEPTIDE AND GH RELEASING HORMONE STIMULATE GH RELEASE FROM SUBPOPULATIONS OF SOMATOTROPHS IN RATS", Journal of neuroendocrinology, 8(11), 1996, pp. 825-830

Abstract

The synthetic hexapeptide GH-releasing peptide (His-D-Trp-Ala-Trp-D-Phe-Lys-NH2; GHRP-6) and GH releasing hormone (GHRH) are both potent stimulators of GH release in rats. Using reverse hemolytic plaque assay (RHPA), we have compared the effects of human GHRH and GHRP-6 on GH release from the dispersed individual cells of rat anterior pituitary. In a single RHPA, we quantified the percentage of plaque forming cells (% PFC) and their mean plaque area (MPA) after 30 min-incubation, and calculated a total secretion index (TSI) by multiplying % PFC and MPA.10 nM GHRH and 100 nM GHRP-6 each caused a significant increase in % PFC (%) (GHRH 39.15, GHRP-6 29.4, vs vehicle 24.3, P<0.01), MPA(x10(-2) mu m(2)) (GHRH 124.04, GHRP-6 94.80, vs Vehicle 44.57, P<0.01) and TSI (x 10(-2)) (GHRH 54.46, GHRP-6 32.87, VS vehicle 10.84, P<0.01). Simultaneous addition of both secretagogues caused a further increase inGH release (% PFC 46.4, MPA 142.55, TSI 69.82, P<0.01 vs vehicle), although the effect was additive but not synergistic. Somatostatin analog, SMS201-995 (SMS) partially suppressed all parameters in GH secretion after stimulation by GHRH and/or GHRP-6. A double RHPA was then performed to test whether all somatotrophs respond equally to GHRH and GHRP-6 or some cells formed plaques only by either GHRH or GHRP-6. There were somatotrophs responsive to only GHRH (23.3% vs control 6.2%, P<0.01), those responsive to only GHRP-6 (11.9% vs control 6.1%, P<0.01), and those responsive to both GHRH and GHRP-6 (7.8% vs control 0.2%, P<0.01). These results confirmed the previous findings that GHRP-6 and GHRH directly but independently stimulate GH release from the pituitarycells, and further suggest the presence of at least three functionally distinct somatotroph subpopulations concerning the responsiveness toGHRP-6 and GHRH in rats.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 15/07/20 alle ore 08:49:43