Somatostatin secretion and action in the regulation of growth hormone secretion

Lawrence A. Frohman, Thomas R. Downs, Mirtha Kelijman, Iain J. Clarke, Greg Thomas

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The inhibition of growth hormone (GH) secretion by the hypothalamic peptide, somatostatin, is mediated by two critical factors: the concentration of the peptide in hypothalamic portal plasma and the number of somatostatin (SRIF) receptors on the somatotroph. The secretory patterns of SRIF and GH-releasing hormone (GRH) in portal blood of unanesthetized sheep is pulsatile and a close relationship of GRH pulses to those of GH secretion was documented, while those of SRIF appear to have more of a modulatory role on the responses to GRH. Peripheral infusion of SRIF at a rate to provide concentrations comparable to those in the portal system leads to a desensitization of SRIF effects on the somatotroph, likely mediated by down-regulation of SRIF receptors. These effects are believed to modulate the GH responses to GRH secretion in the generation of pulsatile GH secretion.

Original languageEnglish
Pages (from-to)43-45
Number of pages3
JournalMetabolism: Clinical and Experimental
Issue number9 SUPPL. 2
Publication statusPublished - 1 Jan 1990
Externally publishedYes

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