[Effect of brain angiotensin II on LH release]

Renin-angiotensin system is present in brain and independent of the peripheral renin-angiotensin system. The effect of brain angiotensin II (A II) on LH release is: (1) Ovarian steroids affect the direction of the LH responses to brain exogenous A II. In the absence of estradiol and progesterone, A II inhibits pulsatile LH release, whereas after treatment with estrogen, A II does not modify LH level. In animals pretreated with both estradiol benzoate and progesterone, exogenous A II stimulated the release of LH; (2) Brain endogenous A II may be involved in the preovulatory release of LH on proestrus; (3) A II affects LH secretion via LH-RH and norepinephrine in the brain.