To evaluate the heparin effects in vivo and in vitro on adrenal angiotensin II receptors and angiotensin II-induced aldosterone production, we examined the angiotensin II binding and the maximum angiotensin II-induced aldosterone production using adrenal glomerulosa cells from rats treated with a heparin preparation containing benzyl alcohol (1500 IU/kg, twice daily for 6 weeks) or cells to which heparin (300 IU/l) was directly added. Comparison was made using the cells from rats treated with vehicle or the cells to which vehicle was directly added. Specific binding of [125I]iodo-angiotensin II was decreased in the cells from heparin-treated rats or in the heparin-treated cells. Scatchard analysis showed that the decrease in binding was due to a decrease in both the number and the affinity of angiotensin II receptors in the cells from heparin-treated rats and a decrease in the number, but not the affinity, of the receptors in the heparin-treated cells. Heparin also caused a decrease in the maximum angiotensin Il-induced production, but not the basal production, of aldosterone in the cells from hepari n\x=req-\ treated rats and in the heparin-treated cells. These data suggest that heparin interacts with adrenal angiotensin II receptors to inhibit the angiotensin Il-induced aldosterone production.

Altered sodium intake is known to cause a greater change in plasma 18-hydroxycorticosterone (18-OHB) level than in plasma aldosterone level, resulting in an increase of plasma 18-OHB/aldosterone ratio in sodium-depleted man and rats. To evaluate the role of endogenous angiotensin II in the high plasma 18-OHB/aldosterone ratio in sodium-depleted rats, we examined the effect of the angiotensin I converting enzyme inhibitor SQ 14225 on plasma 18-OHB and aldosterone in sodium-depleted (SD) and sodium-repleted (SR) conscious rats. Plasma renin activity (PRA) and plasma angiotensin II were higher in the SD rats than in the SR rats. The ingestion of SQ 14225 caused an increase in PRA and a decrease in plasma angiotensin II, whereas these changes were more prominent in the SD rats than in the SR rats. Plasma 18-OHB and aldosterone levels were higher in the SD rats than in the SR rats. The plasma 18-OHB/aldosterone ratio was also higher in the SD rats than in the SR rats. The ingestion of SQ 14225 caused decreases in plasma 18-OHB and aldosterone levels in both the SR and SD rats, whereas the SQ 14225-induced decreases in plasma 18-OHB and aldosterone levels were more prominent in the SD rats than in the SR rats. Thus, the ingestion of SQ 14225 induced a decrease in the plasma 18-OHB/aldosterone ratio in both the SR and SD rats. The decrease in plasma 18-OHB/aldosterone ratio was more prominent in the SD rats than in the SR rats.(ABSTRACT TRUNCATED AT 250 WORDS)