Prostaglandin E2 and reproduction in the male crested newt,Triturus carnifex (Laur.)

Pituitary adenylate cyclase-activating polypeptide induces testicular testosterone synthesis through PGE(2) mediation in crested newt, Triturus carnifex

The aim of the present work was to study the possible role of adenylate cyclase-activating polypeptide (PACAP) 38 in the testicular intracellular mechanism regulating steroidogenesis of crested newt, Triturus carnifex. Gonads were incubated in vitro with PACAP 38 and prostaglandin (PG) E(2) alone or with inhibitors of cyclooxygenase (COX), adenylate cyclase (AC), and phospholipase C (PLC) for 30 min and 60 min. PGE(2), PGF(2 alpha), testosterone, and estradiol-17 beta were measured in the culture medium; aromatase (AR) activity and cAMP were assessed in the tissue. PACAP 38 increased PGE(2) (30 min and 60 min), estradiol-17 beta (60 min), cAMP (60 min), and AR (60 min) but decreased testosterone (60 min). PGE(2) increased estradiol-17 beta, cAMP, and AR and decreased testosterone at 30 and 60 min.PLC inhibitor counteracted the effects of PACAP 38, while AC inhibitor counteracted these effects except for PGE(2) increase. AC inhibitor counteracted the effects of PGE(2), while PLC did not. COX inhibitor decreased PGF(2 alpha) (30 min and 60 min), PGE(2) (30 min and 60 min), estradiol-17 beta (60 min), cAMP (60 min), and AR (60 min), but increased testosterone (60 min). These in vitro results suggest that, in newt testis, PACAP 38 acts on PLC, inducing the increase of PGE(2) which, in turn, acting on AC, increases AR activity with the consequent estradiol-17 beta increase and testosterone decrease.

Cellular mechanism of substance P in the regulation of corticosteroid secretion by newt adrenal gland

In this work, we have studied the effects and the possible cellular mechanism of Substance P (SP) on corticosteroid secretion by the adrenal gland of the urodele crested newt, Triturus carnifex. Adrenals were in vitro superfused with SP, prostaglandin E2 (PGE2), nitric oxide (NO) donor, cyclic GMP (cGMP) analogue, and inhibitors of phospholipase A1, phospholipase A2 (PLA2), phospholipase C, adenylate cyclase (AC), cyclooxygenase (COX), NO synthase (NOS), and soluble guanylate cyclase (sGC). PGE2, corticosterone, and aldosterone release and NOS activity were determined. SP, PGE2, NO donor, and cGMP analogue increased corticosterone and aldosterone; SP and PGE2 increased NOS, and SP increased PGE2. PLA2, AC, COX, NOS, and sGC inhibitors counteracted SP and PGE2 effects, except for PLA2, which did not affect PGE2. These results suggest that SP exhibits a stimulatory role on the corticosteroidogenesis of T. carnifex adrenal gland. In particular SP enhances PLA2 activity, increasing PGE2; this prostaglandin affects AC, which, in turn, enhances NO, and the latter therefore affects sGC, with the consequent corticosteroidogenesis increase.

A possible role of prostaglandin E2 in reproduction of the male water frog, Rana esculenta. In vivo and in vitro studies

Plasma prostaglandin E2 (PGE2), prostaglandin F2 alpha (PGF2 alpha), androgens and estradiol-17 beta were measured in the male water frog, Rana esculenta, during the annual sexual cycle. In vivo experiments were carried out to study the effects of PGE2 and PGF2 alpha on plasma sex steroids during the following periods: prereproduction (April), reproduction (May), postreproduction (June) and recovery (October). In the same months, in vitro experiments were performed to evaluate the effects of these two prostaglandins (PGs) on testicular release of sex steroids. The PGE2 plasma levels peaked in April. PGE2 treatment in vivo increased androgens in April and October, while PGF2 alpha increased estradiol-17 beta in June and October. In in vitro experiments, PGE2 increased androgens in April, while PGF2 alpha increased estradiol-17 beta in October. These results suggest that PGE2 could induce the breeding activity, probably through androgens synthesis. PGF2 alpha could interrupt the breeding, through estradiol-17 beta secretion.