Metabolic changes in coho and chinook salmon resulting from acute insufficiency in pancreatic hormones

Abstract

Acute deficiency in pancreatic peptides (insulin, somatostatin-25, glucagon, and glucagon-like peptide) was invoked for 9-12 hr in coho, Oncorhynchus kisutch, and chinook, O. tshawytscha, salmon by administration of specific antisera raised against purified salmon hormones. Insulin-deficient fish were hyperglycemic, had diminished glycogen content in the liver (Plisetskaya et al., '88a, elevated liver triacylglycerol lipase activity, and higher concentration of plasma triiodothyronine (T3) compared to a control group of fish injected with nonspecific rabbit serum. After immunoneutralization of somatostatin-25, fish remained normoglycemic, with higher liver glycogen content, decreased lipase activity, and elevated plasma levels of insulin, while the levels of T3 declined. The induced deficiency in glucagon family peptides led to comparatively smaller changes: liver glycogen content was increased after anti-glucagon-like peptide (aGLP) injection and transient hyperglycemia was apparent following anti-glucagon (aGLU) administration. Circulating levels of insulin remained unaffected for at least 9 hr following aGLU and aGLP treatments. The velocity of pyruvate kinase at 2.5 mM phosphoenolpyruvate (V2.5) was depressed, especially after the combined administration of aGLU + aGLP. The effectiveness of immunoneutralization experiments was greatly dependent on the particular stage of the fish life cycle. Antisera against fish pancreatic peptides proved to be a suitable tool in the studies of hormonal regulation of fish metabolism.

Physiology of fish endocrine pancreas

“…The action of SSTs are opposite to those of insulin, which is a lipogenic hormone. In salmon treated with anti-SST-25 serum, liver triacylglycerol lipase activity is substantially lowered, while AIS administered in the same experiment elevates lipase activity (Plisetskaya et al 1989b). At this time, it is difficult to decide whether the metabolic effects of salmon SST-25 are direct or indirect.…”

Effect of Alloxan and Insulin Immunoneutralization on Circulating Thyroid Hormone Levels in Larval Landlocked Sea Lampreys, Petromyzon Marinus

“…These data are consistent with those for hagfish, another cyclostome, in which INS insufficiency 24 hr after guinea pig anti-human INS serum administration resulted in a decline of plasma T 3 levels (Plisetskaya et al ., 1983). In contrast, salmon had a higher concentration of plasma T 3 12 hr after the administration of anti-salmon INS serum (Plisetskaya et al ., 1989). This suggests that the mechanism of TH regulation by INS in teleosts and cyclostomes is fundamentally different.…”

“…Twelve to 14 hr after the last injection, individual animals were anesthetized with 0.05% tricaine methanesulfonate. Acute neutralization of pancreatic hormones was induced essentially as previously described by Plisetskaya et al (1989). Groups of 10 larvae received an intraperitoneal injection of 10 µ l/g body weight of 1:1 mixture of 0.6% saline and either anti-lamprey INS or normal rabbit serum (control).…”

Effect and the related signaling pathways of insulin influencing lipid metabolism in yellow catfishPelteobagrus fulvidraco

“…In this sense, the results are often contradictory. Several studies have suggested the anti-lipolytic effect of insulin (Harmon and Sheridan, 1992;Plisetskaya et al, 1989) and an insulin-induced increase of lipid storage in many fish (Cowley and Sheridan, 1993;Plagnes-Juan et al, 2008;Ellesat et al, 2011). In contrast, some authors found that this pathway remained unaffected by insulin (Plagnes-Juan et al, 2008;Warman and Bottino, 1978).…”