Contribution of galanin to stress-induced impairment of insulin secretion in swimming mice.
This study examines the potential role of the neuropeptide, galanin, in stress-induced inhibition of insulin secretion in swimming mice. Firstly, the pancreatic and adrenal content of galanin-like immunoreactivity was determined in mice after swimming stress. It was found that pancreatic content was significantly lower in stressed mice than in resting controls, both after 2 (P less than 0.05) and 6 (P less than 0.025) minutes of swimming, suggesting partial release of pancreatic galanin during stress. In contrast, the adrenal content of galanin-like immunoreactivity did not change during the swimming stress. Gel filtration of tissue extracts indicated that (1) mouse pancreas contains two forms of galanin-like immunoreactivity; one co-eluting with synthetic porcine galanin (centered on Kav of 0.70) and another with a larger molecular weight (centered on Kav of 0.30), and (2) mouse adrenal contains a small void volume-peak and a larger peak of immunoreactivity, the latter co-eluting with synthetic galanin. Secondly, the effects of swimming stress on plasma glucose and insulin levels were compared in mice that received high titre rabbit anti-galanin serum with those in mice receiving normal rabbit serum. In normal rabbit serum-pretreated swimming mice, glucose-induced insulin levels were only 50% of resting controls (P less than 0.01). Immunoneutralization of galanin with specific antiserum abolished this swimming stress-induced inhibition of glucose-stimulated insulin levels. This was accompanied by a modestly enhanced rate of glucose disappearance. These findings suggest that pancreatic galanin is released during swimming stress in mice and that endogenous galanin makes a major contribution to stress-induced impairment of insulin secretion.
Dunning
B E
BE
Division of Endocrinology and Metabolism, VA Medical Center, Seattle, WA 98108.
Karlsson
S
S
Ahrén
B
B
D000311:Adrenal Glands / Q000737:chemistry*; D000818:Animals; D000906:Antibodies / Q000276:immunology / Q000502:physiology; D019004:Galanin; D005947:Glucose / Q000378:metabolism; D007328:Insulin / Q000378:metabolism*; D000078790:Insulin Secretion; D007515:Islets of Langerhans / Q000737:chemistry*; D051379:Mice; D010179:Pancreas / Q000737:chemistry*; D010455:Peptides / Q000032:analysis / Q000276:immunology / Q000502:physiology*; D013312:Stress, Physiological / Q000503:physiopathology*; D013550:Swimming
D000906:Antibodies; D007328:Insulin; D010455:Peptides; D019004:Galanin; D005947:Glucose