Detalle de: Effects of human insulin‐like growth factor‐I on release of growth hormone by rainbow trout ( Oncorhynchus mykiss ) pituitary cells

A recombinant human IGF‐I (rhIGF‐I) was applied to primary cultures of rainbow trout pituitary cells. In wells containing 3 × 10 4 and 6 × 10 4 cells/well, rhIGF‐I inhibited basal GH release both in short (6 h) and long (12 and 24 h) exposures. The decline in GH release was dose‐dependent over the range of 0.01 and 100 mM. The combination of rhIGF‐I and low concentrations of synthetic somatostatin 14 (SRIF) enhanced the inhibitory effect of rhIGF‐I in an additive manner. Any appreciable effect of rhIGF‐I on PRL release was not evidenced. To our knowledge, this report demonstrates for the first time the participation of IGFs on the inhibitory component of fish GH regulation. © 1992 Wiley‐Liss, Inc.