Physiological insulin action is opposed by beta-adrenergic mechanisms in dogs.
To investigate the possible role of adrenergic mechanisms in modulating glucose homeostasis during physiological insulin changes, we studied the effects of alpha-, beta-, or combined alpha- and beta-adrenergic blockade on glucose production (Ra) and utilization (Rd) via isotope ([3-(3)H]glucose) dilution during nonstressful, nonhypoglycemic conditions in response to physiological insulin changes in conscious dogs. Without adrenergic blockade, infusion of insulin at 0.275 mU.kg-1.min-1 (control) caused glucose to fall from 92 +/- 4 to 82 +/- 4 mg/dl over 30 min, because of transient fall in Ra from 2.8 +/- 0.4 to 2.3 +/- 0.3 mg.kg-1.min-1, which recovered to base line by 30 min. There was a later rise in Rd to 3.9 +/- 0.4 mg.kg-1.min-1 at 45 min, but no counter-regulatory hormonal changes (glucagon, cortisol, epinephrine, and norepinephrine) to account for these findings in glucose kinetics. alpha-Blockade alone led to an initial rise in base-line insulin and consequent fall in glucose, associated with a transient fall in Ra but no change in Rd; infusion of insulin led to a further small fall in glucose, with no change in Ra, but with a rise at 30 min in Rd similar to controls. beta-Blockade alone led to an initial fall in insulin and modest rise in glucose; insulin infusion led to a greater rate of fall in glucose than in controls (from 112 +/- 6 to 78 +/- 7 mg/dl over 30 min).(ABSTRACT TRUNCATED AT 250 WORDS)
D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology; D000319:Adrenergic beta-Antagonists / Q000494:pharmacology; D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D004285:Dogs; D004837:Epinephrine / Q000097:blood; D005260:Female; D005934:Glucagon / Q000097:blood; D005943:Gluconeogenesis; D006854:Hydrocortisone / Q000097:blood; D007328:Insulin / Q000097:blood / Q000502:physiology*; D009638:Norepinephrine / Q000097:blood; D011943:Receptors, Adrenergic, beta / Q000502:physiology*
D000317:Adrenergic alpha-Antagonists; D000319:Adrenergic beta-Antagonists; D001786:Blood Glucose; D007328:Insulin; D011943:Receptors, Adrenergic, beta; D005934:Glucagon; D006854:Hydrocortisone; D009638:Norepinephrine; D004837:Epinephrine