Implantation of rainbow trout Oncorhynchus mykiss with somatostatin-14 (SS-
14) for 20 days resulted in reduced food conversion as well as significant
growth retardation compared to controls. Relative growth as mass was reduce
d by 20%, whereas relative growth by length was reduced by 45%. A single in
traperitoneal injection of SS-14 reduced plasma levels of growth hormone (G
H), insulin-like growth factor-1 (IGF-I) and insulin. SS-14 injection also
reduced [S-35]-sulphate incorporation into gill cartilage compared to salin
e-injected fish. In addition, br vitro incubation of gill cartilage with SS
-14 reduced [S-35]-sulphate incorporation in a dose-related manner. These r
esults indicate that SS-14 inhibits growth of rainbow trout and suggests th
at SS-14. in addition to influencing GH, may play an extra-pituitary role i
n the modulation of the GH-IGF-I axis. (C) 2001 The Fisheries society of th
e British Isles.