[Effects of beta-adrenergic blocking with propranolol on the mechanisms of glucose regulation in the dog]. / Efectos del bloqueo beta-adrenérgico con propranolol sobre los mecanismos de regulación de la glucemia en el perro.

Propranolol (P) administration is known to cause hypoglycemia in insulin-dependent diabetic patients. The mechanisms whereby this response is produced remain controversial. Some authors postulate an inhibition in the beta-adrenergic action of catecholamines, responsible for hepatic glycogenolysis, while others indicate that these hormones are not so important in the regulation of blood sugar (BS) level. The present studies were undertaken to assess the mechanism whereby hypoglycemia is developed in the dog, with or without beta-adrenergic blockade. Unanesthetized male mongrel dogs were used, weighing 10-20 kg body wt., fed on dog chow pellets and water ad libitum up to 18-22 hours before the test performances. The dogs were randomly grouped into two groups, A and B in which the effect of P on several hormonal and metabolic responses basally and during insulin (I) test, were respectively studied. Group A was constituted by two subgroups of 6 animals each; the animals of one subgroup were beta-blocked, receiving P p.o. for 10 days (80 mg every 8 hours); the dogs of the remaining subgroup received only P excipient in the same way as the treated ones, for the same period. As P treatment was completed, blood samples were taken by venipuncture, in a peripheral vein, at 0 and 60 min. Some biological controls of beta-blockade, assessed at 0, 30 and 60 min, indicated that mean pulse rate (+/- SE) in the control dogs was 123 +/- 2, 128 +/- 2 and 128 +/- 3 beats/min while in the P treated ones was 106 +/- 2, 103 +/- 1 and 103 +/- 3 respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Efectos del bloqueo beta-adrenérgico con propranolol sobre los mecanismos de regulación de la glucemia en el perro. / [Effects of beta-adrenergic blocking with propranolol on the mechanisms of glucose regulation in the dog]

Propranolol (P) administration is known to cause hypoglycemia in insulin-dependent diabetic patients. The mechanisms whereby this response is produced remain controversial. Some authors postulate an inhibition in the beta-adrenergic action of catecholamines, responsible for hepatic glycogenolysis, while others indicate that these hormones are not so important in the regulation of blood sugar (BS) level. The present studies were undertaken to assess the mechanism whereby hypoglycemia is developed in the dog, with or without beta-adrenergic blockade. Unanesthetized male mongrel dogs were used, weighing 10-20 kg body wt., fed on dog chow pellets and water ad libitum up to 18-22 hours before the test performances. The dogs were randomly grouped into two groups, A and B in which the effect of P on several hormonal and metabolic responses basally and during insulin (I) test, were respectively studied. Group A was constituted by two subgroups of 6 animals each; the animals of one subgroup were beta-blocked, receiving P p.o. for 10 days (80 mg every 8 hours); the dogs of the remaining subgroup received only P excipient in the same way as the treated ones, for the same period. As P treatment was completed, blood samples were taken by venipuncture, in a peripheral vein, at 0 and 60 min. Some biological controls of beta-blockade, assessed at 0, 30 and 60 min, indicated that mean pulse rate (+/- SE) in the control dogs was 123 +/- 2, 128 +/- 2 and 128 +/- 3 beats/min while in the P treated ones was 106 +/- 2, 103 +/- 1 and 103 +/- 3 respectively.(ABSTRACT TRUNCATED AT 250 WORDS)