Effect of Triparanol (MER/29) on Gorticosterone Secretion by Rat Adrenals.

Abstract

Triparanol, which blocks conversion of 24 dehydrocholesterol to cholesterol, is used as a serum cholesterol lowering agent. It also reduces tissue cholesterol in rats. Since cholesterol is a precursor of adrenal steroid hormones, it was thought that triparanol might reduce corticosteroid secretion. Therefore, the effect of this agent on corticosterone production was studied. Two groups of male rats were given triparanol, 30 mg/kg daily by stomach tube. Controls were given vehicle only. One group was treated 25 days, the other 35 days. Adrenal vein blood was collected by renal vein cannulation and plasma corticosterone measured. After 25 days, mean plasma corticosterone level was 12.8 [plus or minus] 8gamma/ml in treated rats and 17.5 [plus or minus] 1.4gamma/ml in controls. After 35 days, mean corticosterone levels were 9.85 [plus or minus]9gamma/ml in treated and 16.5 [plus or minus] 2.6gamma/ml in control rats (p< 0.05, in both). Mean corticosterone secretion rates were 56.3 [plus or minus] 6.4 gammaAr in treated rats and 71.4 [plus or minus] 5.7gamma/hr in controls after 25 days; after 35 days mean secretion rates were458 [plus or minus] 3.3gamma/hr in treated and 76.3 [plus or minus] 10.1 gammaAr in control groups (p < 0.05 in 35 day group). Total adrenal cholesterol in treated groups was about 25% that of controls. These results demonstrate that triparanol results in decreased corticosterone secretion by the rat adrenal.