The regulation of prolactin cells in the rainbow trout (Oncorhynchus mykiss). 2. Somatostatin.
The regulation of rainbow trout prolactin (PRL) cells has been investigated. (PRL) cell activity was assessed using acid gel electrophoresis to measure PRL release in vitro and image analysis to measure PRL cell nuclear area, an index of synthetic activity. Somatostatin (SRIF) reduced PRL release during a 3-hr incubation, but not during 18 hr unless the protease inhibitor, bacitracin, was included in the medium. Synthesis during 18 hr was inhibited by SRIF, an effect also enhanced by bacitracin. The effect of SRIF appears to be relatively short-lived, presumably due to proteolytic degradation. The SRIF antagonist cyclo[7-aminohepatanoyl-Phe-D-Trp-Lys-Thr(BZL)] blocked the inhibitory effect of SRIF. A 48-hr pretreatment with 17 beta-oestradiol to stimulate PRL cell activity did not prevent the inhibitory effects of SRIF, rather the response was enhanced. This evidence further supports a role for SRIF in regulation of rainbow trout PRL secretion.
Williams
A J
AJ
School of Pure and Applied Biology, University of Wales, Cardiff, UK.
Wigham
T
T
D000595:Amino Acid Sequence; D000818:Animals; D001414:Bacitracin / Q000494:pharmacology; D002467:Cell Nucleus / Q000187:drug effects / Q000648:ultrastructure; D004958:Estradiol / Q000494:pharmacology; D005260:Female; D008969:Molecular Sequence Data; D017686:Oncorhynchus mykiss; D010902:Pituitary Gland / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D011388:Prolactin / Q000378:metabolism*; D013004:Somatostatin / Q000031:analogs & derivatives / Q000037:antagonists & inhibitors / Q000494:pharmacology*
D001414:Bacitracin; D004958:Estradiol; D013004:Somatostatin; C043820:cyclo(7-aminoheptanoylphenylalanyl-tryptophyl-lysyl-benzylthreonyl); D011388:Prolactin