In the present study we have examined the effects of androgens and estrogens on circulating arginine vasopressin (AVP). Adult male Wistar rats had serum AVP levels of 0.4 microU/ml. Two weeks after bilateral castration, AVP rose to 2.6 microU/ml, but daily testosterone administration (100 microgram/100 g BW) to the castrate males prevented the AVP increase (0.8 microU/ml). During a normal estrous cycle, adult female Wistar rats had AVP values of 0.6 microU/ml during diestrus, 4.6 microU/ml on the morning of proestrus, 1.3 microU/ml on the afternoon or proestrus, and 1.5 microU/ml on the day of estrus. These changes in AVP paralleled the presumed changes in serum estradiol. Two weeks after bilateral ovariectomy of the adult female rats, AVP was 1.4 microU/ml but daily estradiol injections (100 microgram/100 g BW) to the castrate females produced a rise of serum AVP to 5.0 microU/ml. The results suggest an androgen inhibition and an estrogen stimulation of serum AVP levels.

No abstract

No abstract