Effects of mepartricin, a polyene macrolide agent, on fecal excretion and serum concentration of estrogen and number of prostatic estrogen receptors in immature rats.

Mepartricin, an antifungal agent, was investigated for effects on fecal excretion and serum concentration of sex steroids and the number of sex steroid prostatic receptors in immature rats. Mepartricin was orally administered at 2.5, 5, and 10 mg/kg once daily for 2 weeks. Fecal estrogen and testosterone excretions, serum estrogen, testosterone and luteinizing hormone concentrations, and numbers of prostatic estrogen and androgen receptors were assayed. Prostate weight was also monitored. Fecal estrogen excretion showed a dose-dependent increase, which was significant for the two higher dosages. Conversely, the serum estrogen concentration and prostatic estrogen receptors were significantly decreased. No significant changes in fecal testosterone excretion, serum testosterone and luteinizing hormone concentrations, and prostatic androgen receptors were observed. Prostate weight was significantly reduced at 5 mg/kg, but we did not observe dose-dependency. Mepartricin increases fecal excretion of estrogen by binding with it in the intestinal tract, which results in reducing the serum estrogen concentration and number of prostatic estrogen receptors.