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Titolo:
RELATIVE ROLES OF THECA AND GRANULOSA-CELLS IN OVARIAN FOLLICULAR STEROIDOGENESIS IN THE AMPHIBIAN, RANA-NIGROMACULATA
Autore:
KWON HB; AHN RS;
Indirizzi:
CHONNAM NATL UNIV,DEPT BIOL KWANGJU 500757 SOUTH KOREA
Titolo Testata:
General and comparative endocrinology
fascicolo: 2, volume: 94, anno: 1994,
pagine: 207 - 214
SICI:
0016-6480(1994)94:2<207:RROTAG>2.0.ZU;2-2
Fonte:
ISI
Lingua:
ENG
Soggetto:
DIFFERENT DEVELOPMENTAL STAGES; PROGESTERONE PRODUCTION; STEROID-PRODUCTION; OOCYTE MATURATION; PREOVULATORY FOLLICLES; XENOPUS-LAEVIS; EXTERNA CELLS; INVITRO; PIPIENS; BIOSYNTHESIS;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
24
Recensione:
Indirizzi per estratti:
Citazione:
H.B. Kwon e R.S. Ahn, "RELATIVE ROLES OF THECA AND GRANULOSA-CELLS IN OVARIAN FOLLICULAR STEROIDOGENESIS IN THE AMPHIBIAN, RANA-NIGROMACULATA", General and comparative endocrinology, 94(2), 1994, pp. 207-214

Abstract

Using frog ovarian follicles in vitro we assessed the role of the theca/epithelium (THEP) layer and granulosa cells in the production of steroids. The THEP layer and granulosa cell-enclosed oocytes (GCEOs) were separated from ovarian follicles of the frog, Rana nigromaculata, bymicrodissection. Intact follicles (IFs), THEP layer, or GCEOs were cultured for 6 hr in amphibian Ringer's in the presence or absence of Various steroid precursors (100 ng/ml) or of frog pituitary homogenate (FPH, 0.05 gland/ml). The amounts of progesterone (P-4), 17 alpha-hydroxyprogesterone (17 alpha-OHP4), androstenedione (AD); testosterone (T), and estradiol (E(2) secreted into the medium by the different types of follicular components during culture were measured by radioimmunoassay. Addition of pregnenolone resulted in a marked increase in P-4 concentrations produced by GCEOs (1858 pg/follicle) and IFs (1549 pg/follicle), but a much smaller increase in P-4 occurred in the THEP layer (427 pg/follicle). Likewise, addition of P-4 stimulated greater production of 17 alpha-OHP4 by GCEOs (659 pg/follicle) and by IFs (877 pg/follicle) than by the THEP layer (330 pg/follicle). Exogenous 17 alpha-OHP4 markedly increased AD levels secreted by GCEOs (1139 pg/follicle) and by IFs (841 pg/follicle), but not by the THEP layer (<15 pg/follicle). In contrast, AD addition resulted in the secretion of markedly elevated levels of T by the THEP layer (2326 pg/follicle) and IFs (3652 pg/follicle) as compared to the GCEOs (408 pg/follicle). Addition of T markedly increased E(2) concentrations produced by GCEOs (378 pg/follicle) and by IFs (673 pg/follicle), but not by the THEP layer (< 12 pg/follicle). Without addition of FPH or steroid precursors, none of the follicular components examined produced significant amounts of the steroids measured (<20 pg/follicle). Denuded oocytes incubated in the presence of exogenous substrates or FPH secreted nearly nondetectable amounts of steroids. These data suggest that the main sites for synthesisof P-4, 17 alpha-OHP4, AD, and E(2) are granulosa cells and those of T are the theca/epithelium layer in amphibian ovarian follicles. (C) 1994 Academic Press, Inc.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 04/12/20 alle ore 06:49:41