A cytochemical and ultrastructructural study of the rat ovary in varied functional states

Al-Mehdi, Maytham I.A (1975) A cytochemical and ultrastructructural study of the rat ovary in varied functional states. University of Southampton, Doctoral Thesis.

Abstract

Ovarian tissues from rats at differing ages and functional states were studied by light and electron microscopy. Frozen sections were incubated for the demonstration of five hydrolytic enzymes. Histochemically marked alkaline phosphatase activity was mainly restricted to blood vessel walls, but contrary to the results of many previous' workers a cellular reaction was obtained in granulosa cells. The acid,hydrolases each showed a similar distribution pattern. They were generally localised in the germinal epithelium, granulosa cells', theca cells, oocytes, luteinn cells and interstitial cells as well as in macrophages... It: was found thatwith each significant increase in the production' of steroids there was an associated rise in the intensity of the enzyme reactions suggesting that these enzymes play a role in steroid ogenesis. In addition, however, increased .activity also occurred with the onset of follicular atresia and of regressive changes in corpora lutea. This high level of activity was partly due to the '-creased population of invading macrophages' as well as to autolytic changes in the degenerating cells.The electron cytochemical results confirmed the histochemistry. Reaction product for acid phosphatase and aryl sulphatase was localised in lyscsomes,' multivesicular bodies, Golgi complex and within cisternae of endoplasmic-reticulum. In addition to plasma membranes, the reaction product for alkaline ' phosphatase was seen' in lysosome-like bodies, in smooth endoplasmic reticulum and in occasional Golgi elements of theca and granulosa cells, interstitial cells, lutein cells- and, vascular endothelial cells.The theca interns,, interstitial and lutein cells showed' fine structural features considered typical and characteristic of cells concerned with steroid secretion. Whorls of smooth endoplasmic reticulum were found in intimate, relationship with mitochondria and lipids.Theca lutein cells differed from granulosa lutein by their smaller size, and irregular contours, with shorter microvilli and fewer organelles. Regressive lutein cells were recognized by an increased population of lysosomes, autophagic vacuoles, aligned membranes and myelin-like figures,. andby' the reduction in cytoplasmic content of organelles. .It was observed that interstitial cells originate'.,from (1) proliferation' and ingrowth of the the ca interna cells of atretic follicles, (2) differentiation from the ca externs cells through transient intermediate stages. The origin of lysosomes from Golgi'saccules,'smooth 'endoplasmic membranes and pinocytotic invagination of plasma membranes has been inferred on the. basis of morphology and the electron cytochemical localizationn of the enzymes within these structures.. Evidence was also noted for the origin' of multivesicular bodies from intrusion of the plasma membrane on itself to surround`,collections of smooth vesicles taken in from the exterior.

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