[The effect of prostaglandin D2 on rat testicular testosterone levels].

In vivo effects of prostaglandin D2 (PGD2) on rat testicular testosterone levels were studied. Testosterone levels were determined by HPLC after 6 hours of PGD2 and of hCG. The testosterone levels were decreased by dose of 500 micrograms/rat intraperitoneal injection. Testis testosterone levels were subsequently decreased by intratesticular injection with PGD2 (1.0 micrograms) into the right testis. The left testis received vehicle alone for control. The increase in testosterone levels induced by hCG (50, 100 and 500 unit/rat s.c.) were also inhibited by intraperitoneal injection of 500 micrograms of PGD2. On the other hand, intratesticular injection of hCG (0.01, 0.1 and 1.0 unit/testis) caused an increase in testosterone levels according to dose of hCG. The increase in testosterone levels by hCG was inhibited by simultaneous injection of PGD2 (1.0 micrograms/testis). These results suggest that PGD2 may play an inhibitory action on LH action in androgen synthesis in the rat testis.