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Titolo:
PROSTAGLANDIN PRODUCTION AND OVULATION DURING EXPOSURE OF AMPHIBIAN OVARIAN FOLLICLES TO GONADOTROPIN OR PHORBOL ESTER IN-VITRO
Autore:
CHANG KJ; KIM JW; LEE J; IM WB; KWON HB; SCHUETZ AW;
Indirizzi:
CHONNAM NATL UNIV,DEPT BIOL KWANGJU 500757 SOUTH KOREA CHONNAM NATL UNIV,CTR HORMONE RES KWANGJU 500757 SOUTH KOREA JOHNS HOPKINS UNIV,SCH HYG & PUBL HLTH,DEPT POPULAT DYNAM BALTIMORE MD 21205
Titolo Testata:
General and comparative endocrinology
fascicolo: 3, volume: 100, anno: 1995,
pagine: 257 - 266
SICI:
0016-6480(1995)100:3<257:PPAODE>2.0.ZU;2-J
Fonte:
ISI
Lingua:
ENG
Soggetto:
PROTEIN-KINASE-C; TROUT SALVELINUS-FONTINALIS; GOLDFISH CARASSIUS-AURATUS; OOCYTE MATURATION; RANA-DYBOWSKII; POSSIBLE INVOLVEMENT; INVITRO; CAMP; INDOMETHACIN; COMPONENTS;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
24
Recensione:
Indirizzi per estratti:
Citazione:
K.J. Chang et al., "PROSTAGLANDIN PRODUCTION AND OVULATION DURING EXPOSURE OF AMPHIBIAN OVARIAN FOLLICLES TO GONADOTROPIN OR PHORBOL ESTER IN-VITRO", General and comparative endocrinology, 100(3), 1995, pp. 257-266

Abstract

Experiments were carried out at different times of hibernation to ascertain whether prostaglandin is produced by Rana ovarian follicles during gonadotropin- or 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced in vitro ovulation. Ovarian fragments were cultured in amphibian Ringer in the presence or absence of frog pituitary homogenate (FPH, 0.05gland/ml) or TPA (1 or 10 mu M). After various periods of culture, incidence of ovulation was determined and prostaglandin F-2 alpha (PGF(2alpha)) accumulated in culture medium was measured by radioimmunoassay. FPH and TPA increased PGF(2 alpha) levels in medium in a dose-dependent manner. The time course of PGF(2 alpha) secretion and ovulation by FPH or TPA treatment varied during the hibernation period. In early-hibernation, FPH stimulated neither PGF(2 alpha) secretion nor ovulation while TPA stimulated PGF(2 alpha) secretion, although it failed to induce ovulation. In mid-hibernation, FPH and TPA effectively stimulated PGF(2 alpha) secretion and ovulation, but both events took place several hours later than those observed in late-hibernation. Some fragments obtained in mid-hibernation and most obtained in late-hibernation spontaneously produced PGF(2 alpha) in vitro without FPH or TPA treatment and in some instances spontaneously ovulated. Furthermore, FPH or TPA increased PGF(2 alpha) levels further or accelerated the time course of secretion by such fragments. In late hibernation, PGF(2 alpha) secretion induced with FPH or TPA increased simultaneously with or later than onset of ovulation. Exogenous cAMP (2.5 mu M) or 1-(5-isoquinolinylsulfonyl)-2-methylpiperazine (H-7, 100 mu M), a PKC inactivator, markedly suppressed FPH- or TPA-stimulated PGF(2 alpha) secretion and ovulation in mid-hibernation. Indomethacin (IM, 5 mu g/ml) strongly suppressed TPA- or FPH stimulated PGF(2 alpha) production by fragments but its effect on ovulation varied among animals and at different times. IM suppressed ovulation of some ovarian fragments obtained in mid-hibernation, but failed to suppress hormone-induced ovulation in late-hibernation. Cycloheximide (5 mu g/ml) and actinomycin D (1 mu g/ml) effectively suppressed FPH stimulated PGF(2 alpha) production and ovulation, whereas actinomycin D reduced but failed to significantly suppress TPA-induced PGF(2 alpha) production in mid-hibernation. In general, effects of ovulation inhibitors exhibited strong seasonal variations andwere less efficient as the breeding season approached. Taken together, the data suggest that elevated levels of PGF(2 alpha) are associatedwith spontaneous and hormone-induced ovulation, and PKC mediates gonadotropin induction of PGF(2 alpha) but not steroid synthesis in Rana ovaries. (C) 1995 Academic Press, Inc.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 03/12/20 alle ore 21:52:28