GnRH and substance P regulate prostaglandins and sex steroids from reptilian (Podarcis sicula sicula) ovarian follicles and corpora lutea.

The in vitro effects of salmon gonadotropin-releasing hormone (sGnRH), substance P (SP), and their antagonists on prostaglandin F2 alpha (PGF2 alpha), prostaglandin E2 (PGE2), progesterone, androgens, and estradiol-17 beta release by follicles and corpus luteum (CL) of the oviparous lizard, Podarcis sicula sicula, were studied. Follicles and CL were divided according to the different developmental stages; follicles: pre-vitellogenic, early-vitellogenic, mid-vitellogenic, and fully grown; CL: CL1 (unshelled eggs in the oviducts), CL2 (shelled eggs in the oviducts), CL3 (eggs laid 6 hr previously), and CL4 (eggs laid 48 hr previously). SGnRH increased PGF2 alpha and progesterone release by mid-vitellogenic and fully grown follicles; SP increased PGE2 and estradiol-17 beta release by pre-vitellogenic, mid-vitellogenic, and fully grown follicles. SGnRH and SP decreased PGE2 and progesterone and increased PGF2 alpha by CL1 and CL2. The antagonists of these two neuropeptides induced the opposite effects of those of sGnRH and SP. The present data indicate that sGnRH and SP play different roles in the regulation of prostaglandins and sex steroid production by ovarian follicles and CL of P. s. sicula.