title: Previous exposure to glucose enhances somatostatin secretion from the isolated perfused rat pancreas.
abstract: Previous exposure to glucose enhances insulin and depresses glucagon secretion by the pancreas. We have investigated whether secretion of somatostatin is also influenced by a glucose priming effect. In perfused rat pancreas from 36 h fasted rats a 5 min pulse of arginine (8 mmol/l) rapidly elicited a peak of somatostatin release. A similar somatostatin response was evoked by a second, identical, pulse of arginine after perfusion with "basal" glucose (3.9 mmol/l) for 45 min. On the other hand when 27.7 mmol/l D-glucose, was administered for 20 min between arginine pulses, there was significant stimulation of somatostatin secretion. When arginine was re-introduced 15 min after the cessation of the pulse of elevated glucose the magnitude of the arginine-induced peak (min 0-2 of stimulation) was increased from 16.2 +/- 4.1 to 33.1 +/- 4.7 pg/2 min, p less than 0.01, relative to the first stimulation with arginine. None of these effects of glucose could be reproduced by D-galactose. The somatostatin response to arginine was higher in pancreata from fed than from 36 h fasted animals as was also basal release (22.8 +/- 5.0 vs 9.0 +/- 2.0 pg/min). In the fed state the response to the second pulse of arginine was however reduced by 50% after perfusion with "basal" glucose. This decrease in responsiveness was counteracted by perfusion with 27.7 mmol/l glucose for 20 min between the arginine pulses. It is concluded that previous exposure to an elevated concentration of glucose enhanced D-cell responsiveness to arginine in the fasted as well as the fed state.
mesh_terms: D000818:Animals; D001120:Arginine / Q000494:pharmacology; D005215:Fasting; D005934:Glucagon / Q000378:metabolism; D005947:Glucose / Q000494:pharmacology*; D066298:In Vitro Techniques; D007328:Insulin / Q000378:metabolism; D000078790:Insulin Secretion; D007515:Islets of Langerhans / Q000187:drug effects / Q000378:metabolism*; D007700:Kinetics; D008297:Male; D010477:Perfusion; D051381:Rats; D013004:Somatostatin / Q000378:metabolism*
chemical_list: D007328:Insulin; D013004:Somatostatin; D005934:Glucagon; D001120:Arginine; D005947:Glucose