Cysteamine and the endocrine pancreas: immunocytochemical, immunochemical, and functional aspects.
To evaluate the previously reported depletion of pancreatic somatostatin by cysteamine (beta-mercaptoethylamine), mice were injected subcutaneously with the drug at 300 mg/kg. Immunocytochemical analysis performed on sections from tissue taken at 4 h after the injection revealed an elimination of somatostatin-14-like immunoreactivity without alterations in the somatostatin-28(1-12)-like immunoreactivity. In sections from tissues taken at 24 h after injection, no differences between cysteamine-injected animals and controls were observed. Immunochemical analysis of somatostatin-14-like immunoreactivity in pancreatic extracts showed a significant reduction of the concentration (P less than 0.001). In contrast, no change in the insulin concentration was observed. Functionally, cysteamine lowered the plasma glucose levels at 1 h after injection; this effect persisted for 6 h. Plasma insulin levels were likewise reduced transiently by cysteamine. Concomitant administration of somatostatin did not influence these effects of cysteamine. The plasma glucose-lowering effect of cysteamine was seen also in alloxan-diabetic mice. We conclude that cysteamine alters the immunoreactive characteristics of pancreatic somatostatin without affecting the immunoreactivity of insulin, and that cysteamine transiently reduces plasma glucose and insulin levels.
Ahrén
B
B
Department of Pharmacology, Lund University, Sweden.
Böttcher
G
G
Ekman
R
R
Sundler
F
F
D000818:Animals; D001786:Blood Glucose / Q000378:metabolism*; D003543:Cysteamine / Q000494:pharmacology*; D005260:Female; D007150:Immunohistochemistry; D007328:Insulin / Q000097:blood; D007515:Islets of Langerhans / Q000187:drug effects / Q000378:metabolism*; D051379:Mice; D010455:Peptides / Q000378:metabolism*
D001786:Blood Glucose; D007328:Insulin; D010455:Peptides; C029993:somatostatin-like peptides; D003543:Cysteamine