In the present study, the pressor activity of 19-hydroxyandrostenedione (19-OH-AD) (which is a kind of androgen) and the presence or absence of the possibility of its role as an amplifier of mineralocorticoid were investigated. 34 Wistar rats of 8 weeks of age were used as the experimental subjects. The rats were divided into 3 groups, the control group (n = 12), 19-OH-AD group (n = 12) and DOCA group (n = 10). The control group was given 0.2 ml of sesame oil, the 19-OH-AD group was given 10 mg of 19-OH-AD dissolved in 0.2 ml of sesame oil, and the DOCA group was given 10 mg of DOCA dissolved in 0.2 ml of sesame oil. This was subcutaneously administered three times a week for 4 weeks, and body weight and blood pressure were observed. At the termination of the experiment, blood was sampled by decapitation, and the serum sodium concentration, erythrocyte sodium content, plasma renin activity (PRA), plasma atrial natriuretic hormone (alpha-rANP), and contents of DOC, corticosterone and aldosterone in adrenal gland were determined. The following results were obtained. The blood pressure at the termination of the experiment was higher than that at the initiation of the experiment by 9.9 +/- 1.9 (S.E.), 31.3 +/- 1.7, and 46.2 +/- 2.0 mmHg in the control, 19-OH-AD and DOCA groups, respectively, where significant elevations were observed in both the 19-OH-AD and DOCA groups as compared with the control group. As to the serum sodium concentration, only the DOCA group showed a significant elevation (p less than 0.001) as compared with the other two groups. However, the erythrocyte sodium contents of both the 19-OH-AD and DOCA groups increased significantly as compared with the control group. Moreover, the increase of the DOCA group was significantly higher (p less than 0.001) than that of the 19-OH-AD, and a significant positive correlation between the elevation of blood pressure and the erythrocyte sodium content was observed (p less than 0.001). As to the PRA value, only the DOCA group showed a significant lowering as compared with the other two groups, whereas alpha-rANP value of the DOCA group showed a significant elevation as compared with the other two groups. As to the contents of steroid hormones in the adrenal gland, all of the steroid hormones were significantly lower in the DOCA group, while those of the 19-OH-AD group were unchanged as were those of the control group.(ABSTRACT TRUNCATED AT 400 WORDS)