Role of Adrenal Steroids on the Cardiac c-AMP Response to Isoprenaline in the Rat

Summary

The effect of adrenalectomy on the basal cardiac c-AMP level and the elevated c-AMP level induced by intravenous administration of isoprenaline (10 mcg/kg) were determined by radio-protein assay. The basal cardiac c-AMP level was not altered by adrenalectomy. But the cardiac c-AMP responses to isoprenaline was significantly less in adrenalectomized rats, maintained with 1 % sodium chloride solution for one week; this effect, however, disappeared when animals were maintained for 2 or 4 weeks. This could not be restored by acute administration of dexamethasone (100 mcg/rat). The possible reasons for these effects of adrenalectomy are discussed.

Key-Words:

Adrenalectomy - c-AMP - Isoprenaline - Radio-Protein Assay - Sham Operated Rat - Cardiac Output (CO) - Total Peripheral Resistance (TPR) - Catecholamines - β-A drenoceptors