Ovarian steroid and vasoconstrictor effects on cochlear blood flow.

Ovariectomized rats received intra-arterial infusions of phenylephrine and nicotine. Estrogen treatment for five days prior to these challenges diminished laser Doppler measures of cochlear blood flow (CBF) responses to phenylephrine and blood pressure responses to nicotine. Progesterone enhanced CBF responses to both phenylephrine and nicotine; combined progesterone and estrogen treatment enhanced blood pressure responses to phenylephrine. These results suggest that ovarian steroid-mediated cardiovascular effects may influence cochlear blood flow and potentially hearing functions.