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

✍ Scribed by Gobbetti, Anna ;Zerani, Massimo

• Publisher: John Wiley and Sons
• Year: 1992
• Tongue: English
• Weight: 852 KB
• Volume: 263
• Category: Article
• ISSN: 0022-104X
• DOI: 10.1002/jez.1402630208

✦ Synopsis

Abstract

Plasma prostaglandin E~2~ (PGE~2~) and sex hormones (progesterone, androgens, and 17β‐estradiol) were determined in the male crested newt, Triturus carnifex, during the annual sexual cycle. In vivo experiments were carried out to study the effects of PGE~2~ on plasma sex hormones during prereproduction, reproduction, and postreproduction; contemporaneously, in vitro experiments were performed to study the effects of PGE~2~ on the testicular release of sex hormones. The effects of one week's captivity on PGE~2~ and sex hormones was also evaluated. Plasma PGE~2~ increases in autumn, during the recovery of gonad and secondary sexual characteristics; it peaks in January, at the start of reproduction, and decreases during reproduction to peak again in April, at the end of reproduction. Plasma sex hormones show trends similar to those found in previous studies. In autumn, PGE~2~ and androgen patterns are positively correlated, whereas the April PGE~2~ peak coincides with a drop in plasma androgens. In vivo and in vitro experiments suggest the causal relation between PGE~2~ and androgens. When injected in prereproductive newts or added to cultured testis in this period, PGE~2~ increases androgen production. An opposite in vivo and in vitro effect is obtained during reproduction. These findings suggest that PGE~2~ is involved in inducing the autumnal recovery of gonad and secondary sexual characters (through the stimulation of androgen production), and in terminating the breeding processes (through the inhibition of androgen production and/or clearance). Finally, captivity causes a decrease of plasma PGE~2~, androgens, and estradiol, a phenomenon quite common in captive vertebrates. © 1992 Wiley‐Liss, Inc.