The synthesis and effects of prostaglandins on the ovary of the crab Oziotelphusa senex senex

The possible involvement of prostaglandins in the regulation of ovarian development in the crab Oziotelphusa senex senex was investigated. Uptake of labelled arachidonic acid into the ovary of the crab was significantly greater than the other tissues. Prostaglandin H synthase activity was significantly increased in the ovary during the late vitellogenic stage when compared to immature ovary. The biosynthesis of different prostaglandins in the ovary was also measured during the crab reproductive cycle. Injection of prostaglandin F 2α and prostaglandin E 2 significantly increased ovarian index and oocyte diameter in a dose-dependent manner. In contrast, injection of prostaglandin D 2 did not affect ovarian growth. These results demonstrate the presence of prostaglandin biosynthetic system in ovary of the fresh water crabs.