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Titolo:
STEROIDOGENIC SHIFT BY CULTURED OVARIAN FOLLICLES OF RANA-DYBOWSKII AT BREEDING-SEASON
Autore:
AHN RS; KO SK; BAI DG; YOON YD; KWON HB;
Indirizzi:
CHONNAM NATL UNIV,DEPT BIOL KWANGJU 500757 SOUTH KOREA CHONNAM NATL UNIV,DEPT BIOL KWANGJU 500757 SOUTH KOREA HANYANG UNIV,DEPT BIOL SEOUL 133791 SOUTH KOREA
Titolo Testata:
The Journal of experimental zoology
fascicolo: 3, volume: 267, anno: 1993,
pagine: 275 - 282
SICI:
0022-104X(1993)267:3<275:SSBCOF>2.0.ZU;2-Y
Fonte:
ISI
Lingua:
ENG
Soggetto:
DIFFERENT DEVELOPMENTAL STAGES; OOCYTE MATURATION; PLASMA-LEVELS; OVULATORY CYCLE; SEX STEROIDS; PROGESTERONE; PIPIENS; INVITRO; INVOLVEMENT; GONADOTROPIN;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
29
Recensione:
Indirizzi per estratti:
Citazione:
R.S. Ahn et al., "STEROIDOGENIC SHIFT BY CULTURED OVARIAN FOLLICLES OF RANA-DYBOWSKII AT BREEDING-SEASON", The Journal of experimental zoology, 267(3), 1993, pp. 275-282

Abstract

The steroid secretory activity of cultured ovarian follicles of Rana dybowskii and the activities of relevant steroidogenic enzymes were examined during the natural hibernation period (October-February). Enzyme activities were measured indirectly by monitoring the conversion of exogenous substrates to products by isolated follicles. Follicles wereincubated for 6 h in amphibian Ringer in the presence or absence of frog pituitary homogenate (FPH, 0.1 pituitary/2 ml) and/or various steroid precursors. Progesterone (P-4), 17 alpha-hydroxyprogesterone (17 alpha-OHP) or testosterone (T) secreted by the follicles into the medium were measured by RIA. In the presence of FPH, high levels of P-4 were produced by follicles at the early and mid-hibernation period (695 and 898 pg/follicle, respectively) whereas markedly elevated levels of P-4 were produced during late hibernation (1,393 pg/follicle) (just prior to or breeding season, February). In contrast, high levels of T were produced by the follicles early in hibernation (1,206 pg/follicle) while negligible levels were produced in late hibernation (69 pg/follicle). Higher levels of 17 alpha-OHP were produced by follicles at early and mid hibernation (594 and 705 pg/follicle, respectively) than in later hibernation (221 pg/follicle). Addition of exogenous pregnenolone markedly increased P-4 levels in a dose-dependent manner when added to follicles at early and late stages of hibernation: FPH addition further enhanced conversion of pregnenolone. Similarly, addition of androstenedione (AD) increased T levels in a dose-dependent manner by thesefollicles. However, following addition of exogenous P-4, less 17 alpha-OHP was produced by follicles collected in late hibernation as compared to those collected earlier. Likewise, addition of 17 alpha-OHP to follicles during late hibernation produced a small increase in T accumulation while a marked increase occurred when follicles were obtained in early hibernation. Taken together, the data indicate that steroidogenesis shifts from T to P-4 late in hibernation and this is probably due to decreases in 17 alpha-hydroxylase and C-17,C-20-lyase activities. (C) 1993 Wiley-Liss, Inc.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 30/11/20 alle ore 00:50:25