Involvement of alpha 2-adrenoceptors in metabolic and hormonal responses to a mixed meal in beagle dogs.
The effects of alpha 2-adrenoceptor blockade or activation on glucose, insulin, free fatty acids (FFA), and glycerol responses to a mixed meal were studied in the beagle dog. The alpha 2-adrenoceptor antagonist deriglidole (1 mg/kg po), administered 45 min before feeding, significantly reduced glycemia and increased insulin, FFA, and glycerol levels. Although the alpha 2-adrenoceptor agonist UK-14.304 (3 micrograms/kg sc), administered 15 min before feeding, had no effect per se, it completely blocked meal-induced insulin release, thus promoting a mild increase in glycemia, and prolonged the meal-induced FFA decrease. Deriglidole antagonized the reduction of insulin secretion and the hyperglycemia induced by UK-14.304. The meal-induced fall in FFA levels was still observed after deriglidole treatment and was markedly amplified when UK-14.304 was administered with deriglidole. These results suggest that, in the dog, insulin release and lipolysis are very sensitive to alpha 2-adrenoceptor stimulation. It is also suggested that the meal-evoked decrease in lipid mobilization results from an increase in alpha 2-adrenoceptor stimulation rather than from an increase in insulin secretion.
Guillot
E
E
Department of Internal Medicine, Synthélabo Recherche, Rueil-Malmaison, France.
Morand
R
R
Bouloy
C
C
Eon
M T
MT
Angel
I
I
D000316:Adrenergic alpha-Agonists / Q000494:pharmacology; D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology; D000821:Animal Feed; D000818:Animals; D001786:Blood Glucose / Q000378:metabolism*; D000068438:Brimonidine Tartrate; D004285:Dogs; D004435:Eating; D005230:Fatty Acids, Nonesterified / Q000097:blood*; D005260:Female; D005990:Glycerol / Q000097:blood*; D007093:Imidazoles / Q000494:pharmacology; D007211:Indoles / Q000494:pharmacology; D007328:Insulin / Q000097:blood*; D008297:Male; D011810:Quinoxalines / Q000037:antagonists & inhibitors / Q000494:pharmacology; D011942:Receptors, Adrenergic, alpha / Q000502:physiology*
D000316:Adrenergic alpha-Agonists; D000317:Adrenergic alpha-Antagonists; D001786:Blood Glucose; D005230:Fatty Acids, Nonesterified; D007093:Imidazoles; D007211:Indoles; D007328:Insulin; D011810:Quinoxalines; D011942:Receptors, Adrenergic, alpha; D000068438:Brimonidine Tartrate; C097987:deriglidole; D005990:Glycerol