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Changes in the steroidogenic cells of the ovaries in small ruminants-A review

Indian Agricultural Research Journals

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Title Changes in the steroidogenic cells of the ovaries in small ruminants-A review
 
Creator SHARMA, R K
BATRA, S
 
Subject Corpus luteum; Goat; Granulosa; Ovary; Steroidogenic cells; Sheep; Theca
 
Description The small ruminant ovary possesses 5 types of steroidogenic cells, namely (i) theca and (ii) granulosa cells in the developing and atretic follicles, (iii) small and (iv) large luteal cells in the corpus luteum, and (v) the interstitial gland cells (transformed cells of theca interna of atretic follicles). Theca cells relnain steroidogenically active throughout folliculogenesis, whereas the granulosa cells perform steroidogenic activity only in the antral follicles. The granulosa and theca cells luteinize to fonn granulosa and theca luteal cells respectively. The theca interna cells of atretic follicles transform themselves into interstitial gland tissue. After performing their steroidogenic functions for a specific time, these cells regress back to somatic cells under an altered hormonal milleu. Much literature is available on specific aspects of ovarian steroidogenic tissues. The present review article was planned to integrate all the infonnation on steroidogenic cells and to pin point the areas of future research. The steroidogenic cells of small ruminants are characterized by common electron microscopic features like an agranular endoplasmic reticulum, presence of diffuse lipoproteins, Goigi complexes, lipid droplets and vesicular mitochondria with tubular cristae. These ultrastructural entities undergo cyclic variations in their structure and function. During regression, the mitochondria become vacuolated and irregular in shape, while the Golgi complexes show heterogenicity in their distribution and vesicles. Vacuoles of different shapes and sizes, with varying electron density, are encountered. The smooth endoplasmic reticulum decreases in size and the nucleus is characterized by degenerative apoptotic changes such as pinching off the pyknotic vesicles, containing condensed nuclear nlaterial. Most of these cells degenerate while the remaining cells regress back to normal somatic cells. Somatic cells under the influence of intraovarian and extraovarian endocrine and growth factors differentiated into specific steroidogenic cells. After performing the specified functions for the specific phase of reproduction, these influencing factors are either withdrawn or de novo synthesized factors trigger the regression of these cells back to the somatic tissues. These cells also reveal cyclic ultrastructural variations in different phases of reproduction, which have been discussed in relation to their functions in small ruminants. 
 
Publisher Directorate of Knowledge Management in Agriculture
 
Contributor —
 
Date 2011-03-10
 
Type info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
—
 
Format application/pdf
 
Identifier http://epubs.icar.org.in/ejournal/index.php/IJAnS/article/view/4755
 
Source The Indian Journal of Animal Sciences; Vol 78, No 6 (2008)
0367-8318
 
Language eng
 
Relation http://epubs.icar.org.in/ejournal/index.php/IJAnS/article/view/4755/1951
 
Rights Copyright (c) 2014 The Indian Journal of Animal Sciences