Differential Inhibition of Growth Hormone Secretion by Analogs Selective for Somatostatin Receptor Subtypes 2 and 5 in Human Growth-Hormone-Secreting Adenoma Cells in vitro

2001 ◽  
Vol 73 (5) ◽  
pp. 344-351 ◽  
Author(s):  
Giovanni Tulipano ◽  
Carlo Bonfanti ◽  
Gabriella Milani ◽  
Bruno Billeci ◽  
Angelo Bollati ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Somatostatin Receptor ◽  
Hormone Secretion ◽  
Growth Hormone Secretion ◽  
Human Growth ◽  
Receptor Subtypes ◽  
Differential Inhibition ◽  
Inhibition Of Growth ◽  
Somatostatin Receptor Subtypes

scholarly journals Identification of the Somatostatin Receptor Subtypes (sst) Mediating the Divergent, Stimulatory/Inhibitory Actions of Somatostatin on Growth Hormone Secretion

Endocrinology ◽  
2006 ◽  
Vol 147 (6) ◽  
pp. 2902-2908 ◽  
Author(s):  
Raúl M. Luque ◽  
Mario Durán-Prado ◽  
Socorro García-Navarro ◽  
Francisco Gracia-Navarro ◽  
Rhonda D. Kineman ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Somatostatin Receptor ◽  
Hormone Secretion ◽  
Growth Hormone Secretion ◽  
Receptor Subtypes ◽  
Somatostatin Receptor Subtypes

Cycloheximide blocks insulin-like growth factor I but not somatostatin inhibition of growth hormone secretion

1987 ◽  
Vol 65 (4) ◽  
pp. 515-519 ◽  
Author(s):  
M. S. Sheppard ◽  
R. M. Bala
Keyword(s):  
Growth Hormone ◽  
Hormone Secretion ◽  
Growth Hormone Secretion ◽  
Protein Synthesis Inhibitor ◽  
Hormone Release ◽  
Growth Hormone Release ◽  
Synthesis Inhibitor ◽  
Inhibition Of Growth ◽  
Igf I

Growth hormone secretion is controlled by the two hypothalamic hormones, growth hormone releasing factor (GRF) and somatostatin. In addition, the insulin-like growth factors (IGF or somatomedins) which are themselves growth hormone dependent, inhibit growth hormone release in vitro, therefore acting to close the negative feedback loop. The studies reported here examine some of the differences between inhibition of growth hormone secretion by somatostatin and IGF-I in vitro. The major finding is that cycloheximide, a protein synthesis inhibitor, blocks inhibition of GRF-stimulated growth hormone release caused by IGF-I, without changing the inhibition caused by somatostatin. The experiments were done by exposing mixed rat adenohypophysial cells to secretagogues with or without cycloheximide for 24 h in a short term culture. Somatostatin (0.6 nM) totally blocked rat GRF (1 nM) stimulated growth hormone release to values 48% of control (nonstimulated values), while IGF-1 (27 nM) only reduced the GRF-stimulated growth hormone release by 27 ± 3% (N = 5). Cycloheximide (15 μg/mL) totally blocked the effect of IGF-I but not somatostatin. A low concentration (0.12 nM) of somatostatin, which only partly inhibited growth hormone release, was also unaffected by cycloheximide. In purified rat somatotrophs, somatostatin (0.1 nM) inhibited GRF-stimulated cAMP levels slightly and reduced growth hormone release while IGF-I (40 nM) had no effect. We suggest that IGF-I inhibits only the secretion of newly synthesized growth hormone, while somatostatin inhibits both stored and newly synthesized growth hormone pools.

Inhibition of growth hormone secretion by activin A in human growth hormone-secreting tumour cells

1991 ◽  
Vol 124 (6) ◽  
pp. 666-671 ◽  
Author(s):  
Masafumi Kitaoka ◽  
Kohji Takano ◽  
Yuji Tanaka ◽  
Itaru Kojima ◽  
Akira Teramoto ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Hormone Secretion ◽  
Growth Hormone Secretion ◽  
Human Growth ◽  
Activin A ◽  
Tumour Cells ◽  
Free Calcium ◽  
Gh Secretion

Abstract. Effect of activin A on growth hormone secretion was studied in primary culture of 8 human GH-secreting adenomas, which were responsive to TRH in vivo. When studied in vitro, basal GH secretion was reduced in all cases when cells were pre-incubated for 48 h with activin A at a concentration of 5×10−9 mol/l or greater. Pretreatment of GH-secreting cells with 1× 10−9 mol/l activin A did not affect either basal secretion or cellular content of GH. These tumour cells also responded to TRH in vitro and the GH response to TRH was completely blocked in cells pretreated with activin A. Activin A slightly reduced the increase in cytoplasmic free calcium concentration induced by TRH. Furthermore, pretreatment of the cells with activin A attenuated GH secretion induced by A23187 or 12-O-tetradecanoyl phorbol-4-acetate, agents which bypass receptor-mediated generation of second messengers. These results indicate that activin A inhibits GH secretion by directly acting on human GH-secreting cells and that activin A inhibits the action of TRH by acting on multiple steps in the messenger system.

Influence of catecholamines, prostaglandins and thyroid hormones on growth hormone secretion by chicken pituitary cells in vitro

1990 ◽  
Vol 7 (1) ◽  
pp. 35-42 ◽  
Author(s):  
Dan J. Donoghue ◽  
Frank M. Perez ◽  
Bruce S.A. Diamante ◽  
Sasha Malamed ◽  
Colin G. Scanes
Keyword(s):  
Growth Hormone ◽  
Thyroid Hormones ◽  
Hormone Secretion ◽  
Growth Hormone Secretion ◽  
Pituitary Cells
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