Gene interactions and pathways from curated databases and text-mining
Can J Physiol Pharmacol 1987, PMID: 2886202

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

Sheppard, M S; Bala, R M

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-I (27 nM) only reduced the GRF-stimulated growth hormone release by 27 +/- 3% (N = 5). Cycloheximide (15 micrograms/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.

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Text Mining Data

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

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

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

growth hormone → GRF: " 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 "

growth hormone ⊣ Somatostatin: " Somatostatin ( 0.6 nM ) totally blocked rat GRF ( 1 nM ) stimulated growth hormone release to values 48 % of control ( nonstimulated values ), while IGF-I ( 27 nM ) only reduced the GRF stimulated growth hormone release by 27 +/- 3 % ( N = 5 ) "

growth hormone ⊣ IGF-I: " Somatostatin ( 0.6 nM ) totally blocked rat GRF ( 1 nM ) stimulated growth hormone release to values 48 % of control ( nonstimulated values ), while IGF-I ( 27 nM ) only reduced the GRF stimulated growth hormone release by 27 +/- 3 % ( N = 5 ) "

growth hormone → GRF: " Somatostatin ( 0.6 nM ) totally blocked rat GRF ( 1 nM ) stimulated growth hormone release to values 48 % of control ( nonstimulated values ), while IGF-I ( 27 nM ) only reduced the GRF stimulated growth hormone release by 27 +/- 3 % ( N = 5 ) "

growth hormone ⊣ somatostatin: " 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 "

growth hormone ⊣ GRF: " 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 "

growth hormone ⊣ IGF-I: " 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 "

Manually curated Databases

No curated data.