Somatostatin inhibits growth of rainbow trout

Abstract

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 reduced by 20%, whereas relative growth by length was reduced by 45%. A single intraperitoneal injection of SS‐14 reduced plasma levels of growth hormone (GH), insulin‐like growth factor‐1 (IGF‐I) and insulin. SS‐14 injection also reduced [35S]‐sulphate incorporation into gill cartilage compared to saline‐injected fish. In addition, in vitro incubation of gill cartilage with SS‐14 reduced [35S]‐sulphate incorporation in a doserelated manner. These results indicate that SS‐14 inhibits growth of rainbow trout and suggests that SS‐14, in addition to influencing GH, may play an extra‐pituitary role in the modulation of the GH‐IGF‐I axis.

The endocrine regulation network of growth hormone synthesis and secretion in fish: Emphasis on the signal integration in somatotropes

“…At the level of the pituitary, SS-14, SS-28, and [Pro2]-SS-14, but not salmonid SS-25, inhibit pituitary GH release [50]. SS-14 injection of rainbow trout disrupts the GH-IGF-1 axis (inducing GH and IGF-1 deficiency) and results in growth retardation [51]. In contrast with mammals, 3 precursors of preprosomatostatin, PPSS I, PPSS II, and PPSS III, have been cloned from such fish species as Russian sturgeon (Acipenser gueldenstaedti Brant), goldfish, African lungfish, zebrafish, rainbow trout and grouper [52][53][54][55][56][57].…”