Prostaglandins and corticosterone in the oviparous female lizard, Podarcis sicula sicula, during reproduction

The in vitro effects of prostaglandin F 2α (PGF 2α ) and prostaglandin E 2 (PGE 2 ) on corticosterone release by ovarian follicles, corpora lutea (CL), and interrenals were studied in the female lizard, Pobarcis sicula sicula, during reproduction. Follicles and CL were divided according to their different developmental stages; follicles: previtellogenic, early-vitellogenic, mid-vitellogenic and fully-grown; CL:CL1 (unshelled eggs in the oviducts), CL2 (shelled eggs in the oviducts), CL3 (eggs laid 6 h previously) and CL4 (eggs laid 48 h previously). Interrenals were divided according to the reproductive stages: pre-vitellogenesis, vitellogenesis, ovulation, post-ovulation, and post-deposition. ' PGF 2α release was highest in fully-grown follicles and PGE 2 in early-vitellogenic follicles, corticosterone was highest in pre-vitellogenic and lowest in early-vitellogenic follicles. PGE 2 decreased corticosterone in pre-vitellogenic, mid-vitellogenic and fully-grown follicles. PGF 2α release was highest in CL4, and PGE, in CL1 and CL2, corticosterone was highest in CL4. PGF 2α increased corticosterone in CL1, CL2 and CL3. In interrenals, PGF 2α release was highest and PGE 2 lowest during ovulation, corticosterone was highest during ovulation. PGF 2α increased and PGE 2 decreased interrenal corticosterone during vitellogenesis, ovulation, and post-ovulation. In the plasma, PGF 2α levels were highest and PGE 2 lowest during ovulation, corticosterone was highest during ovulation. These results suggest that corticosterone, modulated by PGF 2α and PGE 2 , is implied in the reproductive processes with different roles. In fact this steroid could favour ovulatory and luteolytic processes. In addition the hypothesis of an anti-vitellogenic role of corticosterone is discussed