Role of Nitric Oxide in Gonadotropin-
Releasing Hormone-Dependent
Prostaglandin F
2
Synthesis by Frog
(Rana esculenta) Interrenal Gland During
Post-Reproduction
A. Gobbetti,
1
L. Bellini-Cardellini, and M. Zerani
Department of Molecular, Cellular, and Animal Biology, University of
Camerino, Camerino, Italy
The aim of this study was to clarify the possible involvement of nitric
oxide (NO) on prostaglandin (PG) E
2
-9-ketoreductase activity in the
gonadotropin-releasing hormone (GnRH)-dependent PGF
2
synthesis
by the interrenal gland of the female water frog, Rana esculenta, dur-
ing the post-reproduction. Interrenal glands were incubated in vitro
with GnRH, NO donor (sodium nitroprusside, SNP), and inhibitors of
phospholipase C (compound 48/80), inositol triphosphate (decavana-
date), calmodulin (calmidazolium), NO synthase (L-NAME), and
PGE
2
-9-ketoreductase (palmitic acid). Production of PGE
2
and PGF
2
and NO synthase and PGE
2
-9-ketoreductase activities were deter-
mined. GnRH and SNP increased PGF
2
production and PGE
2
-9-ke-
toreductase activity, and decreased production of PGE
2
and GnRH
increased NO synthase activity. GnRH effects were blocked by all in-
hibitors, except for palmitic acid, which did not affect NO synthase
activity, which is increased by GnRH. This study indicates that NO
may be involved in regulation of the R. esculenta post-reproduction
through stimulation of PGE
2
-9-ketoreductase activity in GnRH-depen-
dent PGF
2
synthesis by the frog interrenal gland.
Keywords: Frog; gonadotropin-releasing hormone; interrenal gland; nitric oxide;
prostaglandin E
2
-9-ketoreductase; prostaglandin F
2
; reproduction
1
Address correspondence to: A. Gobetti, University of Camerino Dipartimento de
Biologia MCA via F. Camerini 1, I-62032 Camerino MC, Italy; Phone: 011 39 737
636770; Fax: 011 39 737 636216; E-mail: goz@camserv.unicam.it
Prostaglandins & other Lipid Mediators 55:277–290, 1998
© 1998 by Elsevier Science Inc. 0090-6980/98/$19.00
655 Avenue of the Americas, New York, NY 10010 PII S0090-6980(98)00026-4