AN INVESTIGATION OF THE MECHANISM BY WHICH ESTRADIOL-17 ELEVATES THE EPINEPHRINE CONTENT OF THE RAT UTERUS

¹ Department of Pharmacology, University of Minnesota Medical School, Minneapolis, Minnesota

The subcellular distribution of the catecholamines in the uterus was not altered by administration of estradiol-17 alone or with JB-835 (4-phenyl-2-hydrazinobutane sulfate). Over 50% of the catecholamine content of the uterus was present in the soluble fraction. The significance of this distribution pattern is unsettled since the subcellular distribution of labeled epinephrine added in vitro before homogenization was the same as that for the endogenous amine. The capacity of estrogens to increase the epinephrine content of the uterus was not limited to this organ. Administration of estradiol elevated the epinephrine content of the left ventricle, spleen and adrenal gland; no changes in norepinephrine occurred. The phenylethanolamine-N-methyl transferase activity was not changed in the adrenal glands and heart after estrogen administration; no enzyme activity was detected in the uterus. Neither adrenal demeduilation nor adrenalectomy altered the capacity of estradiol to increase the epinephrine content in this organ.