Expression of androgen receptors and steroidogenic enzymes in relation to follicular growth and atresia following ovulation in pigs

• Published in: Biology of reproduction 1996-11, Vol.55 (5), p.949-955
• Main Authors: Garrett, W.M. (Germplasm and Gamete Physiology Laboratory, ARS, USDA, Beltsville, MD.), Guthrie, H.D
• Format: Article
• Language: English
• Subjects: 3-Hydroxysteroid Dehydrogenases - metabolism; ADN; ANDROGENE; ANDROGENOS; Animals; ANTIGENE; ANTIGENOS; Aromatase - metabolism; Biological and medical sciences; CELLULE; CELULAS; CERDAS; CERDO; CICLO ESTRAL; CITOCROMO P 450; CITOCROMOS; CRECIMIENTO; CROISSANCE; CYCLE OESTRAL; CYTOCHROME; CYTOCHROME P 450; ENZIMAS; ENZYME; Female; Follicular Atresia; Fundamental and applied biological sciences. Psychology; Granulosa Cells - enzymology; Immunohistochemistry; Ki-67 Antigen - analysis; MALFORMACION; MALFORMATION; Mammalian female genital system; METABOLISME DES STEROIDES; METABOLISMO DE ESTEROIDES; Morphology. Physiology; OVAIRE; Ovarian Follicle - growth & development; Ovarian Follicle - physiology; OVARIOS; OVULACION; OVULATION; Ovulation - physiology; OXIDORREDUCTASAS; OXYDOREDUCTASE; PORCIN; PROTEINAS AGLUTINANTES; PROTEINE DE LIAISON; RECEPTEUR D'HORMONE; RECEPTORES DE HORMONAS; Receptors, Androgen - metabolism; Steroid 17-alpha-Hydroxylase - metabolism; Steroids - biosynthesis; Swine; Theca Cells - enzymology; TRUIE; Vertebrates: reproduction
• ISSN: 0006-3363; 1529-7268
• DOI: 10.1095/biolreprod55.5.949

Among the new antral follicles that develop after ovulation in pigs, the incidence of atresia, based on granulosa cell apoptosis, increases between Days 5 and 7 of the estrous cycle. The purpose of this study was to determine how follicular growth and atresia affected the expression of some key enzymes regulating follicular steroidogenesis and androgen receptor on Days 3, 5, and 7 after the onset of estrus. Ovaries were frozen in liquid propane for subsequent sectioning and immunohistochemical analysis. Ninety-six follicles were classified according to size as small ( 3 mm), medium (3-5 mm), or large ( 5 mm). Follicles in the active stages of the cell cycle were identified by the presence of the cell proliferation-associated nuclear antigen Ki-67 in granulosa cells. Follicles with apoptotic cells were identified by in situ 3'-end labeling of DNA. Staining intensity of antigens on sections was assigned a numeric value (0-3). Follicles assigned a value 1 for 3'-end labeling in their granulosa cells were classified atretic. The percentage of atretic follicles increased (p less than or equal to 0.05) from 5% on Days 3 and 5 to 41 % on Day 7. Expression of Ki-67 in granulosa cells was more strongly (p less than or equal to 0.05) associated with nonatretic follicles (98% expressing) than with atretic follicles (41% expressing). Aromatase cytochrome P450 (P450 arom) was localized predominantly in granulosa cells of nonatretic follicles and was undetectable in atretic follicles. Androgen receptor in granulosa cells and expression of P450 17 alpha-hydroxylase/C17-20 lyase (P450c17) in theca interna were lower (p less than or equal to 0.001) in atretic follicles than in non-atretic follicles. The expression of 3 beta-hydroxysteroid dehydrogenase (3betaHSD) was localized to the theca interna and was unaffected by follicle atresia