Androgenic effects on angiotensin II-induced blood pressure and cochlear blood flow changes in rats.

Ovariectomized, castrated, and sham-castrated rats pretreated with oil or testosterone were intra-arterially infused with saline and three doses of angiotensin II while blood pressure and cochlear blood flow were measured. The results indicated a positive dose-response relationship for blood pressure and cochlear blood flow. Sham-castrated males had higher mean blood pressure responses than castrated males, followed by ovariectomized females. Cochlear blood flow responses were higher in the sham-castrated males than the ovariectomized females, followed by the castrated males. In comparison to the male groups, the ovariectomized females evidenced the lowest, middle, and highest cochlear blood flow responses to the three increasing doses of angiotensin II. Testosterone pretreatment facilitated angiotensin-induced cochlear blood flow elevations in all three angiotensin doses. These results suggest that endogenous and exogenous androgens may alter blood pressure and/or cochlear blood flow responses to angiotensin II via different mechanisms.