Growth hormone releasing factor, somatocrinin, releases pituitary growth hormone in vitro.
AUTOR(ES)
Brazeau, P
RESUMO
Purified (rat) hypothalamic growth hormone releasing factor (GRF), native human GRF isolated from an islet cell tumor of the pancreas that had caused acromegaly, and the synthetic replicates of the human material are potent secretagogues of immunoreactive growth hormone (GH) by primary cultures of rat pituitary cells. Native or synthetic peptides give identical dose-response curves, with identical slopes and identical maximal effects. The median effective dose of the tumor-derived GRF is 15 x 10(-12) M. The effect of hypothalamic GRF or of a synthetic replicate of tumor-derived GRF is immediate, being demonstrable in less than or equal to 30 sec after contact in a pituitary cell perifusion system. The effect of hypothalamic GRF or of tumor-derived GRF is highly specific for stimulating release of immunoreactive growth hormone; there is no demonstrable concomitant effect on the secretion of other pituitary hormones. Somatostatin-28 and somatostatin-14 inhibit the release of growth hormone produced by hypothalamic GRF or tumor-derived GRF in typical noncompetitive antagonism. On the basis of the results reported here, hypothalamic GRF and tumor-derived GRF are qualitatively indistinguishable in their ability to stimulate the secretion of immunoreactive growth hormone in vitro. The name "somatocrinin" is proposed to replace the acronym GRF.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=347459Documentos Relacionados
- Cloning and sequence analysis of cDNA for the precursor of human growth hormone-releasing factor, somatocrinin.
- Growth hormone-releasing factor stimulates proliferation of somatotrophs in vitro.
- Isolation, primary structure, and synthesis of human hypothalamic somatocrinin: growth hormone-releasing factor.
- Gonadotropin-releasing hormone receptor mRNA expression by human pituitary tumors in vitro.
- Growth hormone-releasing factor regulates growth hormone mRNA in primary cultures of rat pituitary cells.