The in-vitro effects of insulin and the effects of acute fasting on cardiac beta-adrenoceptor responses in the short-term streptozotocin-diabetic rat.
This study demonstrates that in-vitro incubation with insulin results in a reduction of the sensitivity of cardiac tissues from streptozotocin-diabetic rats to isoprenaline. Following incubation with insulin, the sensitivity of left atria and papillary muscles from diabetic animals was not significantly different from those of control animals. Insulin incubation had no effect on the sensitivity of diabetic tissues to forskolin or on ventricular beta-adrenoceptor number. Reduction of blood glucose in the absence of insulin by fasting, did not affect the sensitivity of tissues from diabetic animals to isoprenaline. These results suggest that insulin itself can directly reduce beta-adrenoceptor sensitivity without altering receptor number.
Austin
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C
Department of Pharmacology and Therapeutics, University of Liverpool, UK.
Chess-Williams
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R
D000704:Analysis of Variance; D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D005576:Colforsin / Q000494:pharmacology; D003921:Diabetes Mellitus, Experimental / Q000378:metabolism*; D004082:Dihydroalprenolol / Q000378:metabolism; D005215:Fasting; D005260:Female; D006321:Heart / Q000187:drug effects; D066298:In Vitro Techniques; D007328:Insulin / Q000494:pharmacology*; D007545:Isoproterenol / Q000494:pharmacology; D009206:Myocardium / Q000378:metabolism*; D010210:Papillary Muscles / Q000187:drug effects; D051381:Rats; D017208:Rats, Wistar; D011943:Receptors, Adrenergic, beta / Q000187:drug effects / Q000378:metabolism*; D013311:Streptozocin
D001786:Blood Glucose; D007328:Insulin; D011943:Receptors, Adrenergic, beta; D005576:Colforsin; D013311:Streptozocin; D004082:Dihydroalprenolol; D007545:Isoproterenol