Effect of prostaglandins on ornithine decarboxylase activity in the testis of immature rat.

Intratesticular injection of prostaglandin E2 (PGE2) and F2 alpha (PGF2 alpha) caused stimulation of ornithine decarboxylase (ODC) activity in the testis of immature rats. PGE2 at a dose of 10 microgram per testis was maximally effective 2 hours after the injection. Dibutyryl cyclic AMP (cAMP) and 1 methyl, 3-isobutyl xanthine (MIX), a phosphodiesterase inhibitor, also stimulated ODC activity. Simultaneous injection of PGE2 and FSH or LH caused additional stimulation of ODC activity. Similarly injection of PGE2 in addition to cAMP or MIX also caused increased stimulation of ODC. Indomethacin (IM, 60 microgram/testis) inhibited LH, FSH or cAMP induced ODC activity. However, IM at the same dose inhibited the synthesis of total proteins. These results suggest that PGE2 and PGF2 alpha stimulate the activity of ODC. The action of prostaglandins may be independent of the action of gonadotropic hormones. cAMP appears to mediate the action of prostaglandins in the testis of rat.