Some factors modifying the insulinotropic and cardiovascular effects of isoprenaline in the rat.
The effects of L-isoprenaline on plasma immunoreactive insulin (IRI) and glucose concentrations were examined in pentobarbitone anaesthetized rats. When given by bolus injection hyperinsulinaemia was produced only by very large doses of isoprenaline (100-200 micrograms/kg). Infusion of isoprenaline allowed the demonstration of hyperinsulinaemia at low dose rates (0.07-0.7 microgram kg-1 min-1). Pretreatment with phentolamine or production of a functional sympathectomy by bilateral adrenal demedullation and chronic guanethidine treatment augmented the hyperinsulinaemic effect of isoprenaline. Isoprenaline-induced hyperglycaemia was attenuated by sympathectomy and by phentolamine pretreatment, this attenuation being attributed to the augmented hyperinsulinaemic effect of isoprenaline under these conditions. The increase in heart rate and reduction in blood pressure produced by isoprenaline were also augmented in sympathectomized rats.
D000818:Animals; D001786:Blood Glucose / Q000032:analysis; D001794:Blood Pressure / Q000187:drug effects*; D006339:Heart Rate / Q000187:drug effects*; D007328:Insulin / Q000097:blood*; D007545:Isoproterenol / Q000494:pharmacology*; D008297:Male; D010646:Phentolamine / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D013562:Sympathectomy
D001786:Blood Glucose; D007328:Insulin; D007545:Isoproterenol; D010646:Phentolamine