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Effects of growth hormone‐releasing factor, somatostatin and dopamine on growth hormone and prolactin secretion from cultured ovine pituitary cells
Author(s) -
Law Greg J.,
Ray Keith P.,
Wallis Michael
Publication year - 1984
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(84)80070-8
Subject(s) - somatostatin , prolactin , endocrinology , medicine , secretion , growth hormone , dopamine , chemistry , prolactin cell , hormone , biology
A synthetic form of human pancreatic growth hormone releasing factor (GRF‐44‐NH 2 ) was shown to be a potent stimulator of growth hormone (GH) secretion and cellular cyclic AMP levels in cultured sheep pituitary cells. A small dose‐dependent stimulation of prolactin secretion was also observed. Somatostatin (0.5 μM) completely blocked the maximal GRF (1 nM)‐stimulated secretion without a significant effect on cyclic AMP levels. Dopamine (0.1 μM) inhibited the GRF‐elevated GH secretion by 50% and lowered cyclic AMP levels by 30%. Dopamine (0.1 μM) inhibition of basal prolactin secretion was not affected by GRF (1 nM). The data support the hypothesis that cyclic AMP is involved in the action of GRF but suggest that somatostatin can inhibit GRF‐induced secretion of GH independently of cyclic AMP.