Interaction between gastrin-17 and oxytocin on plasma levels of insulin, glucagon and glucose in conscious dogs.
The aim of the present study was to investigate how infusion of gastrin-17 and oxytocin affects plasma levels of insulin, glucagon and glucose in order to elucidate how the two hormones contribute to metabolic changes seen in situations where they are released, e.g. feeding and suckling during lactation. Thus, gastrin-17 (0.5 and 2.0 nmol kg-1 h-1) and oxytocin (0.11 and 1.1 nmol kg-1 h-1) were infused separately or simultaneously into conscious dogs. Both gastrin-17 and oxytocin induced significant, dose-dependent increases in insulin levels. An additive effect on insulin levels was obtained when gastrin-17 and oxytocin were infused simultaneously. Glucagon levels were not affected by gastrin-17 whereas infusion of 1.1 nmol kg-1 h-1 of oxytocin was followed by a significant increase. In contrast to a slight transient increase in the glucose level induced by oxytocin, infusion of gastrin-17 caused a sustained period of hypoglycaemia. Thus, infusion of gastrin-17 and oxytocin, respectively, gave rise to different ratios between circulating concentrations of insulin and glucagon reflected in different effects on the glucose level. The gastrin-induced hypoglycaemia could reflect that gastrin, via a release of insulin, promotes storing of glucose, e.g. in connection with feeding. That infusion of oxytocin caused a parallel increase in insulin and glucagon levels together with a slight increase in the glucose level could imply that oxytocin favours mobilization of glucose, e.g. during lactation.
Stock
S
S
Department of Pharmacology, Karolinska Institutet, Stockholm, Sweden.
Uvnäs-Moberg
K
K
D000818:Animals; D001786:Blood Glucose / Q000032:analysis*; D004285:Dogs; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D005260:Female; D005755:Gastrins / Q000008:administration & dosage*; D005934:Glucagon / Q000097:blood*; D007328:Insulin / Q000097:blood*; D008297:Male; D010121:Oxytocin / Q000008:administration & dosage*
D001786:Blood Glucose; D005755:Gastrins; D007328:Insulin; D010121:Oxytocin; C013550:gastrin 17; D005934:Glucagon