Interstitial Gland Tissue of Mammalian Ovary

Abstract

1. The interstitial gland cells of the mammalian ovary originate from the theca interna and surrounding stromal elements of degenerating follicles and are simultaneously vascularized, and hypertrophied (or luteinized). They form a specific feature of the mammalian ovary, and are invariably present in the ovaries of young and adult mammals. The interstitial gland cells show several variations in their amount and distribution in different mammals. They also show cycles of abundance and differentiation correlated with the reproductive age and ovarian cycles. 2. The interstitial gland cells possess the cytological, histochemical and biochemical features of well-established steroid-secreting cells. These features are: a) abundant diffuse lipids (lipoproteins) in the cytoplasm, which apparently derive from the abundant ultrastructural agranular endoplasmic reticulum; b) well-developed cell organelles, especially the pleomorphic mitochondria with complex system of internal cristae that are predominantly tubular; c) the development of diffuse lipoproteins (or membranes of smooth reticulum), closely accompanied by the appearance of enzyme activities indicative of the biosynthesis of steroid hormones; d) under certain physiological situations, stored lipid droplets in the cytoplasm, which consist of phospholipids, triglycerides, and cholesterol and/or its esters; and e) the capacity to form steroid hormones in biochemical experiments in vitro and in vivo. The physiological significance of these various features, which do not show any appreciable development in the compressed, relatively embryonic stromal elements of the general ovarian stroma, has been discussed in relation to steroid hormone synthesis in the interstitial gland cells. In general, the results of the cytological, histochemical and biochemical studies agree well with each other and are compatible with their endocrine function.3. After stimulation with endogenous gonadotrophins, the interstitial gland cells undergo conspicuous cytological, histochemical and biochemical changes, which have been correlated to the accelerated production of steroid hormones.4. The formation of androgenic steroids seems to be the principal product of interstitial gland cells; in some mammalian species, oestrogens and progestins are also formed. 5. Further comparative studies on the interstitial gland cells in different mammalian species are suggested to determine the nature and physiological significance of their steroid secretions under different physiological situations.6. Interstitial gland cells of different mammals show several variations with regard to their permanency, apparently depending on some gonadotrophic stimulation. After persisting for some time, they gradually lose their cytoplasm and lipids, and ultimately revert to the relatively embryonic, compressed stromal tissue from which they are originally derived. This cytoplasmic change is closely accompanied by the loss of blood vascularity, which may be providing the gonadotrophic hormone and other nutrient substances ...

Histochemical Observations on the Lipid Changes in the Rat Corpus Luteum During Various Reproductive States

“…A consistent sequence of lipid changes has been shown to occur in a variety of species during the transformation of granulosa to luteal cells (Guraya, 1973). The most important histochemical change is the development of abundant diffuse lipoproteins throughout the cytoplasm and the accumulation of some lipid droplets consisting mainly of phospholipids.…”

“…The diffuse lipoproteins are presumed to derive from the abundant membranes of smooth reticulum, act as a site for enzymes involved in steroidogenesis and may also serve as a reservoir for the storage of hormone precursors (Flint & Armstrong, 1972;Armstrong & Flint, 1973). Active synthesis of a steroid hormone through stimulation by gonadotrophin is thought to occur only when there is no storage of cholesterol and/or its esters (Guraya, 1971(Guraya, , 1973.…”

“…The appearance of diffuse lipoproteins may serve as a useful histochemical indicator of the process of luteinization that occurs in response to vascularization and LH. From these observations, it has been suggested (Guraya, 1971(Guraya, , 1973) that the diffuse lipoproteins and the lipid droplets are intimately connected with steroidogenesis.…”

Fine structure and origin of interstitial tissue in the ovary of the pregnant rat

“…The large body of evidence suggests that secondary interstitial cells arise from the theca interna cells of atretic follicles [Dawson and McCabe, 1951;Guraya and Greenwald, 1964a, b;Guraya, 1973;Malta, 1974], This view has been confirmed in the rat by our own observa tions [Al-Mehdi, 1976], The theory that primary interstitial tissue arises from stromal connective tissue cells has been supported by many workers [Mossman el a i, 1964;Guraya and Greenwald, 1964a, b;Molta et a i, 1971;Deanesly, 1972]. The histochemical findings of Baillie [1966] on developing mouse ovary indicated the differentiation of stromal mesen chymal cells into the primary type of interstitial tissue.…”

Histoarchitecture and Δ5-3β hydroxysteroid dehydrogenase profile in ovaries of the non-pregnant, pregnant and lactating insectivorous rat-tailed bat, Rhinopoma microphyllum kinneari

“…The exact cause of recruitment of follicles, follicular atresia and eventual maturation of a single Graafian follicle remains elusive. This is despite studies that report atresia in ovaries of oriental and occidental chiropterans as well as other mammals (Ingram, 1962;Guraya, 1968Guraya, , 1973Kitchener and Halse, 1978;Fortune, 1994). It is possible that atretic follicles stimulate differentiation of follicles of the next wave of the same cohort in sheep and heifers, but that dominant follicles inhibit differentiation (Ko et al, 1991;Driancourt, 1994).…”