Onset of Steroidogenic Enzyme Gene Expression During Ovarian Follicular Development in Sheep1

<p>Fecundity is a term that refers to the number of offspring produced per female. It combines fertility (i.e. ability to produce offspring) and prolificacy (i.e. number of offspring). Ovulation rate i.e. the number of mature eggs released from the ovaries during one reproductive cycle in sheep, as with other mammals, is controlled by an exchange of hormonal signals between the pituitary gland and the ovary. Genetic mutations affecting ovulation are commonly referred to as the fecundity genes (Fec). The most obvious outcome is the number of offspring produced. There is already evidence of a number of major genes affecting the ovulation rate in sheep, specifically the Booroola, Inverdale, Hanna and more recently the Woodlands gene. The sheep carrying the Woodlands gene arose because the mutation was first recognised on a farm in Woodlands, Southland, New Zealand. Woodlands have a novel, X-linked maternally-imprinted, fecundity trait referred to as FecX2w, where Fec = fecundity, X = X chromosome, 2= 2nd mutation identified on X and W= Woodlands. The studies in this thesis investigated ovarian follicular development in both 4-week old Woodland carrier (W+) and non-carrier (++) lambs and adult ewes and evaluated some aspects of the endocrine interactions between the ovary and pituitary gland. The purpose was to identify potential physiological effects of the FecX2w gene on ovarian function. A confounding issue during these studies was the discovery that a large ovary phenotype (LOP) which was present in many of the W+ but not ++ lambs at 4 weeks of age was in fact a coincidence and not linked to the FecX2w mutation. The key findings from the studies of lambs and/or ewes that were carriers (W+) or non-carriers (++) of the FecX2w gene were: 1. No genotype differences were present either in the numbers of primordial (i.e. Type 1/1a follicles) or developing preantral (i.e. Types 2-4 follicles); 2. Significant genotype differences were present in the numbers of small antral (Type 5) follicles (W+>++; p<0.05); 3. An earlier onset of antral follicular development in W+ vs. ++ ewes with irregularities in morphology between the basement membrane and stroma in the former; 4. No genotype differences in the onset of gene expression during follicular development or in the cell-types expressing GDF9, BMP15, alpha inhibin, beta A inhibin and beta B inhibin, FSHR, ER alpha, or ER beta; 5. No genotype differences in the levels of GDF9 or BMP15 gene expression in oocytes throughout follicular growth; 6. No genotype difference in the diameters that follicles reached in W+ vs. ++ ewes; 7. Some lambs at 4-weeks of age had unusually large ovaries with an exceptional level of antral follicular development that is reminiscent of a polycystic ovarian condition. The underlying cause of this condition is unknown. In conclusion, the physiological characteristics of ovarian follicular development in ewes with the FecX2w gene is different from that in ewes with the Booroola, Inverdale, Hanna or other recently identified mutations.</p>

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Regulation of cell death and cell survival gene expression during ovarian follicular development and atresia

Frontiers in Bioscience ◽

10.2741/949 ◽

2003 ◽

Vol 8 (4) ◽

pp. d222-237 ◽

Cited By ~ 108

Author(s):

Benjamin K Tsang

Keyword(s):

Gene Expression ◽

Cell Death ◽

Cell Survival ◽

Follicular Development ◽

Survival Gene ◽

Ovarian Follicular Development

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The Effects of Leptin and Irisin on Steroidogenic Enzyme Gene Expression in Human Ovarian Granulosa Cells - Initial Studies

Journal of the Endocrine Society ◽

10.1210/jendso/bvab048.1571 ◽

2021 ◽

Vol 5 (Supplement_1) ◽

pp. A772-A773

Author(s):

Dimiter Bogdanov Avtanski ◽

Karina Ziskovich ◽

Tomer Singer ◽

Ariel Yeshua ◽

Tal Cantor ◽

...

Keyword(s):

Gene Expression ◽

Energy Metabolism ◽

Granulosa Cells ◽

Pcr Analysis ◽

Mrna Levels ◽

Steroidogenic Enzyme ◽

Enzyme Gene ◽

Ovarian Granulosa Cells ◽

Brown Adipose

Abstract Fertility and energy metabolism are closely associated, and the cytokines produced by the adipose and muscle tissue play a role in this association. Leptin, predominantly produced by the white adipose tissue, and irisin, produced by the brown adipose and skeletal muscle tissues, are cytokines that are important in balancing energy metabolism. This study aimed to investigate the effects of leptin and irisin on steroidogenic enzyme gene expression in human ovarian granulosa cells in vitro. Granulosa cells were retrieved and isolated from ovarian follicular fluid during in vitro fertilization (IVF) procedures. Cells were placed in primary in vitro cultures and treated with increasing concentrations of leptin (25, 50, 100, 200, and 400 ng/ml) or irisin (125, 250, 500, 1,000, and 2,000 ng/ml) for 24, 48, and 72 hours. mRNA expression levels of CYP11A1, CYP19A1, CYP21A2, HSD3B1, and HSD17B3 were measured by qRT-PCR analysis. Leptin treatment of granulosa cells resulted in significant upregulation of CYP21A2 mRNA levels, while irisin significantly downregulated mRNA levels of CYP11A1, CYP19A1, and HSD3B1. Taken together, these early experiments demonstrate that leptin and irisin may affect steroid hormone production in the ovary by targeting the gene expression of key steroidogenic enzymes. Additional experiments are in progress.

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