Effects of dopamine on cyclic AMP concentration in the anterior pituitary gland in vitro

Effects of different concentrations of dopamine on the cyclic AMP concentration in the anterior pituitary gland were investigated in vitro. Low concentrations of dopamine (10(-9)--10(-8) mol/l) were found to decrease, whereas the high concentration (10(-5) mol/l) increased the cyclic AMP concentration in pituitaries collected from ovariectomized and estradiol-treated females. In contrast, dopamine had no effect on the anterior pituitary cAMP concentration when pituitaries were collected from ovariectomized rats which had not received estrogen replacement. These data show that the action of dopamine on the anterior pituitary cAMP largely depends on the dopamine concentration and the hormonal state of animals.