Effect of Growth Hormone (GH)-Releasing Peptide (GHRP) on the Release of GH from Cultured Anterior Pituitary Cells in Cattle.

Soliman, Ezzat M.; Hashizume, Takumi; Kanematsu, Shigeto

doi:10.1507/endocrj.41.585

Cited by 12 publications

(9 citation statements)

References 25 publications

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“…Synergistic GH response to combined GHRP and GHRH treatments have been reported in cultured rat pituitary cells (35 -37). However, other groups have reported only additive effects with these two peptides in rat (38,39), bovine (40), ovine (41) and human fetal pituitary cultures (13). In the present study, combined treatment with ghrelin analogs and GHRH had an additive effect on GH release from cultured human GH-secreting adenomas.…”

Section: Discussioncontrasting

confidence: 41%

Novel ghrelin analogs with improved affinity for the GH secretagogue receptor stimulate GH and prolactin release from human pituitary cells

Rubinfeld

Hadani²,

Taylor³

et al. 2004

European Journal of Endocrinology

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Objective: Ghrelin, a recently identified 28-amino acid peptide is a potent GH secretagogue (GHS) produced predominantly by the stomach. Ghrelin stimulates GH secretion through binding to the GHS receptor in the hypothalamus and pituitary. In addition to the GH-releasing action, ghrelin has been found to be a powerful orexigenic factor. To assess the direct in vitro effects of ghrelin on human pituitary hormone secretion we have produced a panel of novel ghrelin analogs (molecular weight, 3323 -3384; human native ghrelin, 3371) with enhanced affinity for the human GHS receptor (IC 50 0.38-1.09 nM; human ghrelin, 1.2-2.2 nM). Methods: The peptidic analogs were tested for their effect on GH secretion using dispersed human fetal pituitaries (21 to 23 weeks of gestation) and cultured GH-and prolactin (PRL)-secreting adenomas. The expression of the GHS receptor in normal (fetal and adult) human pituitary tissues, GH-and PRLcell adenomas was established using RT-PCR. Results: The effects of ghrelin, its analogs and GH-releasing hormone (GHRH) alone or in combination on GH and PRL secretion were compared at various concentrations. The ghrelin analogs stimulated GH release by 35-60% from human fetal pituitary cells (1 -10 nM; P , 0.05) and by 50 -75% from cultured pituitary adenomas (10 nM; P , 0.05). This releasing effect was dose-dependent, achieving maximal stimulation with analog concentrations at 100 nM. Human ghrelin was less potent as compared with its analogs in stimulating human GH, in keeping with the improved binding affinity of the analogs for the GHS-1a receptor. The ghrelin analogs and GHRH had comparable effects on GH secretion from both normal and adenomatous cells, and in combination produced an additive stimulatory effect on GH (150%; P , 0.0001). In contrast, ghrelin and its analogs induced a comparable increase in PRL release ranging between 25 and 40% (P , 0.05) from fetal cells and 30 and 70% (P , 0.001) from cultured PRL-cell and mixed GH -PRL adenomas. Conclusions: Our results have demonstrated for the first time that ghrelin analogs with enhanced affinity for the GHS receptor are potent stimulators of GH secretion from human pituitary cells, and thus may possess potential clinical therapeutic benefits.European Journal of Endocrinology 151 787-795

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Section: Discussioncontrasting

confidence: 41%

Novel ghrelin analogs with improved affinity for the GH secretagogue receptor stimulate GH and prolactin release from human pituitary cells

Rubinfeld

Hadani²,

Taylor³

et al. 2004

European Journal of Endocrinology

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“…In this study we confirmed our previous observation [20] that GHRH and SRIF in- teract to regulate GH secretion in cattle. Furthermore, although the increase in VIP-induced bovine GH was blunted by SRIF, VIP significantly reduced the SRIF induced suppression of GH release.…”

Section: Discussionsupporting

confidence: 92%

“…Adenohypophysial cells were enzymatically dispersed by a method previously described by Vale et al [16] and modified in our laboratory [19,20]. The cells (5 x 104 cells/ml) resuspended in Dulbecco's modified Eagle's medium (DMEM) [20] were plated in Costar 24-well dishes and maintained at 37 °C in a humidified atmosphere of 5% CO2.…”

Section: Preparation and Culture Of Adenohypophysial Cellsmentioning

confidence: 99%

“…The cells (5 x 104 cells/ml) resuspended in Dulbecco's modified Eagle's medium (DMEM) [20] were plated in Costar 24-well dishes and maintained at 37 °C in a humidified atmosphere of 5% CO2. The media were changed 2 days after plating.…”

Section: Preparation and Culture Of Adenohypophysial Cellsmentioning

confidence: 99%

“…In cows, earlier studies demonstrated that VIP exerts a direct action on perifused adenohypophysial tissues to induce GH release, and that the effect of VIP is less potent than that of GHRH [14,15] Bovine GH concentrations in media were measured by a validated RIA method previously described by Johke [17]. The GH standard preparation and hormone for iodination were USDA bGH-Bl [19,20]. The least detectable value was 1.5 ng/ml.…”

mentioning

confidence: 99%

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The Interactive Effects of VIP, PHI, GHRH and SRIF on the Release of Growth Hormone from Cultured Adenohypophysial Cells in Cattle.

Soliman

Hashizume

Ohashi³

et al. 1995

Endocr J

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Direct effects of growth hormone (GH)-releasing hexapeptide (GHRP-6) and GH-releasing factor (GRF) on GH secretion from cultured porcine somatotropes

et al. 1998

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Effect of Growth Hormone (GH)-Releasing Peptide (GHRP) on the Release of GH from Cultured Anterior Pituitary Cells in Cattle.

Abstract: Abstract.The effect of His-D-Trp-Ala-Trp-D-Phe-Lys-NH2

Cited by 12 publications

References 25 publications

Novel ghrelin analogs with improved affinity for the GH secretagogue receptor stimulate GH and prolactin release from human pituitary cells

Novel ghrelin analogs with improved affinity for the GH secretagogue receptor stimulate GH and prolactin release from human pituitary cells

The Interactive Effects of VIP, PHI, GHRH and SRIF on the Release of Growth Hormone from Cultured Adenohypophysial Cells in Cattle.

Direct effects of growth hormone (GH)-releasing hexapeptide (GHRP-6) and GH-releasing factor (GRF) on GH secretion from cultured porcine somatotropes

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