Profiling of prostanoids in zebrafish embryonic development.

Prostanoids (PG) play important roles in vascular, pulmonary, reproductive and renal physiology. Little is known about their roles in the embryonic development. Using the oviparous zebrafish embryo as a model, we determined the temporal expression of PGs synthesized from exogenous prostaglandin H(2). Prostaglandin E(2) is the major PG throughout first 120 h post-fertilization (hpf), whereas prostaglandin F(2)(alpha) is at a lower but also a constant level. Reverse transcription-polymerase chain reaction (RT-PCR) showed that transcripts of cytosolic and membrane-bound PGE synthases were evident during the 120 hpf period. Compared with thromboxane A(2), the level of prostacyclin (PGI(2))is higher at first 24 hpf, the stage before the formation of blood vessel. RT-PCR showed that transcript of prostacyclin synthase appeared at 7 hpf whereas thromboxane synthase appeared at 48 hpf, suggesting that PGI(2) has additional functions besides hemostasis. Interestingly, level of prostaglandin D(2) (PGD(2)) followed an exponential decay over 120 hpf with a rate constant of 0.048 h(-1) and transcript of lipocalin-type PGD synthase was expressed at a higher level at early stage of development, suggesting that PGD(2) is highly regulated during embryogenesis.