Nesfatin-1 regulates glucoregulatory genes in rainbow trout (Oncorhynchus mykiss)

The aim of this work was to determine if the anorexigen nesfatin-1 modulates the expression of genes involved in glucoregulation in rainbow trout. First, the nesfatin-1 sequence from trout was confirmed. Second, the effects of 0.1, 1 and 10 nM nesfatin-1 on insulin, glucagon, igf-I, igf-II, glut1, glut2, glut4 and sglt1 expression were tested in cultured liver, gut, muscle and adipose tissue. In liver, the expression of insulin and glucagon isoforms X1 increased after 2 h of incubation with 0.1 nM nesfatin-1, while insulin and glucagon X2 expression increased after 4 h with 1 nM treatment. All nesfatin-1 doses tested decreased glut2 expression after 4 h. In adipose tissue, all nesfatin-1 concentrations reduced insulin X1 expression at 30 min, and 1 nM nesfatin-1 increased insulin X2 expression at 4 h. In gut, 0.1, 1 and 10 nM nesfatin-1 decreased glut2 and sglt1 mRNA levels after 240 min of incubation. In muscle, 0.1 nM nesfatin-1 increased the expression of igf-I after 240 min. The expression of igf-II in muscle increased after 30 min of incubation with 1 and 10 nM nesfatin-1 and after 120 min of incubation with 0.1 and 1 nM nesfatin-1. Expression of glut1 and sglt1 in muscle increased after 240 min of incubation with 0.1 nM nesfatin-1 and after 120 min with 0.1 and 10 nM nesfatin-1, respectively. These results suggest that nesfatin-1 could decrease the gut intake of dietary glucose, and increase its uptake in glucoregulatory tissues such as liver and muscle of rainbow trout.