Restoration of the A cell response to glucose in isolated rat islets of Langerhans.
This study investigated the modulatory effects of forskolin, phorbol 12-myristate 13-acetate (PMA) and arginine on pancreatic glucagon secretion in response to changes in glucose concentrations. Glucose, on its own (0, 5, 9 and 18 mM), did not modify glucagon secretion from A cell-rich isolated rat islets of Langerhans. In the presence of 20 microM forskolin, glucagon release was stimulated dose-dependently on lowering the external glucose concentration to 0 mM. Sensitivity to glucose was achieved in the presence of either PMA or arginine; both agents also significantly enhanced glucagon release at all glucose concentrations tested. The response of the B cells in these experiments were as expected from the available literature. These results indicate that the endogenous rate of glucagon secretion in the isolated islet preparation was minimal and was insensitive to glucose, sensitivity of the A cells to glucose could be restored by either arginine or agents which alter the concentration or activity of proposed cellular second messengers.
D000818:Animals; D001120:Arginine / Q000494:pharmacology; D005576:Colforsin / Q000494:pharmacology; D005934:Glucagon / Q000378:metabolism*; D005947:Glucose / Q000494:pharmacology*; D066298:In Vitro Techniques; D007328:Insulin / Q000378:metabolism*; D000078790:Insulin Secretion; D007515:Islets of Langerhans / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D007700:Kinetics; D051381:Rats; D011919:Rats, Inbred Strains; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
D007328:Insulin; D005576:Colforsin; D005934:Glucagon; D001120:Arginine; D005947:Glucose; D013755:Tetradecanoylphorbol Acetate