Follicle dynamics and aromatase activity in high-ovulating Meishan sows and in Large-White hybrid contemporaries. 1998

A T Miller, and H M Picton, and J Craigon, and M G Hunter
Department of Physiology and Environmental Science, Sutton Bonington Campus, University of Nottingham, Loughborough, United Kingdom.

This study compared the dynamics of follicle development during the follicular phase in Meishan sows (n = 10) with a high ovulation rate, with those in contemporary Large-White hybrid sows (n = 12) (ovulation rates: 27.7 and 17.6, respectively; p < 0.01). Ovaries were recovered on Day 16 or 19 of the cycle, and all follicles > or = 1 mm in diameter were dissected. Fluid was aspirated from all those > or = 2 mm, and the granulosa and theca cells were incubated to estimate aromatase activity and estradiol production. The total number of follicles dissected was higher in Meishan than in Large-White hybrid animals (p < 0.001), and whereas the number decreased (p < 0.01) between Days 16 and 19 in Large-White hybrid sows, there was no significant change in Meishan animals. The mean diameter of Meishan follicles recovered on each of Days 16 and 19 was smaller (p < 0.001) than that of those recovered from Large-White hybrids. Total estradiol production in vitro was higher (p < 0.01) by follicles > or = 2 mm from Meishan sows. There was an interaction (p < 0.01) between day of the cycle, breed, and follicle diameter in aromatase activity in both granulosa cells and theca tissue, and in follicular fluid estradiol concentrations in follicles > or = 2-< 6 mm. The largest three size categories of follicles recovered on Day 19 from each breed were classified as preovulatory (29.0 and 17.7 for Meishan and Large-White hybrid, respectively), and the mean diameter was smaller (p < 0.001) in Meishan animals. Follicular fluid estradiol concentrations and total estradiol synthesis by granulosa and theca combined were higher (p < 0.05) in Meishan than in Large-White hybrid sows. In conclusion, high-ovulating Meishans maintained a higher number of follicles during the follicular phase, which overall synthesized more estradiol in vitro, than did Large-White hybrid animals.

UI MeSH Term Description Entries
D010060 Ovulation The discharge of an OVUM from a rupturing follicle in the OVARY. Ovulations
D002452 Cell Count The number of CELLS of a specific kind, usually measured per unit volume or area of sample. Cell Density,Cell Number,Cell Counts,Cell Densities,Cell Numbers,Count, Cell,Counts, Cell,Densities, Cell,Density, Cell,Number, Cell,Numbers, Cell
D004958 Estradiol The 17-beta-isomer of estradiol, an aromatized C18 steroid with hydroxyl group at 3-beta- and 17-beta-position. Estradiol-17-beta is the most potent form of mammalian estrogenic steroids. 17 beta-Estradiol,Estradiol-17 beta,Oestradiol,17 beta-Oestradiol,Aerodiol,Delestrogen,Estrace,Estraderm TTS,Estradiol Anhydrous,Estradiol Hemihydrate,Estradiol Hemihydrate, (17 alpha)-Isomer,Estradiol Monohydrate,Estradiol Valerate,Estradiol Valeriante,Estradiol, (+-)-Isomer,Estradiol, (-)-Isomer,Estradiol, (16 alpha,17 alpha)-Isomer,Estradiol, (16 alpha,17 beta)-Isomer,Estradiol, (17-alpha)-Isomer,Estradiol, (8 alpha,17 beta)-(+-)-Isomer,Estradiol, (8 alpha,17 beta)-Isomer,Estradiol, (9 beta,17 alpha)-Isomer,Estradiol, (9 beta,17 beta)-Isomer,Estradiol, Monosodium Salt,Estradiol, Sodium Salt,Estradiol-17 alpha,Estradiol-17beta,Ovocyclin,Progynon-Depot,Progynova,Vivelle,17 beta Estradiol,17 beta Oestradiol,Estradiol 17 alpha,Estradiol 17 beta,Estradiol 17beta,Progynon Depot
D004971 Estrus The period in the ESTROUS CYCLE associated with maximum sexual receptivity and fertility in non-primate female mammals.
D005260 Female Females
D006080 Ovarian Follicle An OOCYTE-containing structure in the cortex of the OVARY. The oocyte is enclosed by a layer of GRANULOSA CELLS providing a nourishing microenvironment (FOLLICULAR FLUID). The number and size of follicles vary depending on the age and reproductive state of the female. The growing follicles are divided into five stages: primary, secondary, tertiary, Graafian, and atretic. Follicular growth and steroidogenesis depend on the presence of GONADOTROPINS. Graafian Follicle,Atretic Follicle,Ovarian Follicles,Atretic Follicles,Follicle, Atretic,Follicle, Graafian,Follicle, Ovarian,Follicles, Atretic,Follicles, Graafian,Follicles, Ovarian,Graafian Follicles
D006107 Granulosa Cells Supporting cells for the developing female gamete in the OVARY. They are derived from the coelomic epithelial cells of the gonadal ridge. Granulosa cells form a single layer around the OOCYTE in the primordial ovarian follicle and advance to form a multilayered cumulus oophorus surrounding the OVUM in the Graafian follicle. The major functions of granulosa cells include the production of steroids and LH receptors (RECEPTORS, LH). Cell, Granulosa,Cells, Granulosa,Granulosa Cell
D000818 Animals Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA. Animal,Metazoa,Animalia
D001141 Aromatase An enzyme that catalyzes the desaturation (aromatization) of the ring A of C19 androgens and converts them to C18 estrogens. In this process, the 19-methyl is removed. This enzyme is membrane-bound, located in the endoplasmic reticulum of estrogen-producing cells of ovaries, placenta, testes, adipose, and brain tissues. Aromatase is encoded by the CYP19 gene, and functions in complex with NADPH-FERRIHEMOPROTEIN REDUCTASE in the cytochrome P-450 system. CYP19,Cytochrome P-450 CYP19,Cytochrome P-450(AROM),Androstenedione Aromatase,CYP 19,CYP19 Protein,Cytochrome P450 19,Estrogen Synthase,Estrogen Synthetase,P450AROM,Aromatase, Androstenedione,Cytochrome P 450 CYP19,Protein, CYP19
D013045 Species Specificity The restriction of a characteristic behavior, anatomical structure or physical system, such as immune response; metabolic response, or gene or gene variant to the members of one species. It refers to that property which differentiates one species from another but it is also used for phylogenetic levels higher or lower than the species. Species Specificities,Specificities, Species,Specificity, Species

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