title: The influence of mammalian and teleost somatostatins on the secretion of growth hormone from goldfish (Carassius auratus L.) pituitary fragments in vitro.
abstract: The effect of various vertebrate somatostatins (SRIF) on basal growth hormone (GH) secretion from goldfish pituitary fragments was studied using an in vitro perifusion system. SRIF-14 caused a rapid and dose-dependent decrease in the rate of GH release from goldfish pituitary fragments. The half-maximal effective dose (ED50) of SRIF-14 was calculated as 1.3 nM following exposure to two minute pulses of increasing concentrations of SRIF-14, whereas the ED50 of SRIF-14 calculated after continuous exposure to sequentially increasing doses of SRIF-14 was 65 nM. This difference suggests that the pituitary fragments were less responsive to SRIF-14 in the latter experiment, possibly as a result of previous exposure to SRIF-14. SRIF-28 was found to be equipotent with SRIF-14 in decreasing basal GH secretion from the goldfish pituitary. In contrast, catfish SRIF-22, a uniquely teleost SRIF isolated from catfish pancreatic islets, did not alter GH secretion. These results provide further support for the hypothesis that SRIF-14 or a very similar molecule functions as a GH release-inhibiting factor in teleosts, indicating that this action of SRIF-14 has been fully conserved throughout vertebrate evolution.
mesh_terms: D000818:Animals; D003530:Cyprinidae / Q000502:physiology*; D004334:Drug Administration Schedule; D006054:Goldfish / Q000502:physiology*; D013006:Growth Hormone / Q000378:metabolism*; D066298:In Vitro Techniques; D010902:Pituitary Gland / Q000378:metabolism*; D012636:Secretory Rate / Q000187:drug effects; D013004:Somatostatin / Q000008:administration & dosage / Q000494:pharmacology*; D013329:Structure-Activity Relationship
chemical_list: D013004:Somatostatin; D013006:Growth Hormone