Thickening of the adrenal zona glomerulosa in dogs induced by oxodipine, a calcium channel blocker.

Subchronic effects of oxodipine, a calcium channel blocker affecting the adrenal gland of the dog, are described. Thirteen wk of treatment at a high dose (24 mg/kg/day) of oxodipine resulted in drug-induced thickening of the zona glomerulosa and increased stimulation of its secretory activity. It is postulated that subchronic administration of oxodipine at this dosage resulted in a decrease in blood pressure, with uninterrupted stimulation of the adrenal zona glomerulosa to release aldosterone, causing an increase in the width of this portion of the gland involving cellular hyperplasia. Support for this indirect effect is found in the increased presence of renin granules in the juxtaglomerular apparatus.