Thecal Gland Research Articles

Some seasonal changes in the thecal gland in the ovaries of hibernators ( Citellus citellus L.)

The ovaries of 36 ground squirrels were studied in March, April, July, and December. Morphological and functional seasonal characteristics of theca interna were studied by histological methods, electron microscopy, and quantitative methods for determinating the volume density and histoenzyme activity of NADH 2-tetrazolium reductase, glucose-6-phosphate dehydrogenase, and Δ 5-3β-hydroxysteroid dehydrogenase. Maximal activity of theca interna as a steroid-producing structure was observed during spring awakening. A significant increase in the histoenzyme activity of Δ 5-3β-hydroxysteroid dehydrogenase in December, versus two other enzymes studied, indicated steroid synthesis in theca terna.

Ovarian activity during the annual reproductive cycle and nesting cycle of a wild avian species, the pied myna (Sturnus contra contra)

Ovarian activity was studied during the annual reproductive cycle and nesting cycle in the Indian pied myna (Sturnus contra contra). The investigation was carried out on the basis of gravimetric, histological (gross and quantitative), and histochemical (3β-hydroxysteroid dehydrogenase and lipids) studies. In the ovary of the pied myna, four types of healthy follicles (primordial, small developing, large developing, and yolky) were recognized; the stroma showed gland cells. Steroidogenic activity was marked in the theca and granulosa of the follicles, and it altered with the growth of the follicles. The probable source of stromal gland cells is discussed. The ovarian activity changed over the course of the year with four distinct phases, viz., progressive (February to April), breeding (May), regression (June to July), and nonbreeding (August to January) phases. Ovarian weight, largest follicular diameter, populations of larger follicles, and thecal gland cell mass increased gradually from February through April, became maximal in May, decreased in June and July, and became minimal during August through January. Yolky follicles developed only in May. Stromal gland cell mass was abundant in March, decreased from April to June, was almost absent from July to September, reappeared in October, and gradually increased afterwards. Steroidogenic activity of the thecal and stromal gland cells also changed with the annual ovarian cycle; it was absent during July through September and reappeared in October. The granulosa cells showed steroid activity only in May. During the nesting cycle, ovarian activity increased rapidly from early nest-building to egg-laying periods and declined during incubation and nestling periods; this was evident from changes in ovarian weight, largest follicular diameter, thecal gland mass, and populations of larger follicles. Yolky follicles were seen during late nest-building, egg-laying, and incubation periods. Stromal gland cell mass decreased gradually during the nesting cycle. 3β-Hydroxysteroid dehydogenase activity was maximal in the nest-building period.

Histoenzymological differences in the envelope of white and stages of rapidly growing yellow follicles in the ovary of crow (Corvus splendens)

Histoenzymological differences in the localization and intensities of succinate and lactate dehydrogenases, tetrazolium reductases and steroid dehydrogenases have been studied in the follicular envelope of white and stages of yellow follicles of the crow ovary. The activities of these enzymes in the thecal gland cells show a progressive increase during follicular growth. The granulosa layer of white follicle is devoid of Δ5-3β-hydroxysteroid dehydrogenase which appear and show a gradual increase in the rapidly growing yellow follicles along with other enzymes.

Effects of PCBs on gonads, sex hormone balance and reproduction processes of Japanese quail Coturnix coturnix japonica after ingestion during sexual maturation

Male and female Japanese quail were fed PCB (Clophen A 60) in concentrations of 0, 50, 100 and 150 ppm for three weeks during the maturation period (second to fourth weeks of life). The effects of PCB on gondal histology, on sex hormone concentrations in plasma and gonads and on plasma calcium levels were investigated. PCB effects on subsequent reproductive processes were measured by evaluating laying capacity, egg, eggshell and semen analysis. In females, no PCB effects were detected on ovary and oviduct weight, nuclear volume and lipid content of the thecal gland cells and on plasma 17 β-oestradiol and calcium content. However, liver weights were increased in all PCB-treated groups. PCB caused delayed laying and a diminished laying capacity. Egg and shell weights were either not affected by PCB treatment or were higher in PCB groups. The breaking strength of the eggs was reduced after PCB ingestion. In males, PCB treatment resulted in a trend towards reduced testis weights, in a significantly decreased amount of the testes' seminiferous epithelium and in a smaller nuclear volume of the Leydig cells. The lipid content of the latter was not affected and plasma calcium levels were unchanged. Liver weights in all treatment groups were increased. Plasma concentrations of testosterone (T) and 5 α-dihydrotestosterone (DHT) were not affected by PCB, nor was the DHT content in the testes. T levels in testes were significantly higher after 50 ppm treatment. PCB showed no effect on the percentage of dead spermatozoa in the ejaculates. In another experiment, which consisted of feeding 0 and 150 ppm Clophen, beginning in the first week of life, plasma sex hormone concentrations were measured during the whole experiment from day 24 to day 42 of life. In females, progesterone levels were not greatly affected by PCB but 17 β-oestradiol appeared to be lower before sexual maturity and was more unstable in the PCB group when egg laying occurred. In males, T concentrations were not significantly altered, nor were DHT plasma levels.

Accumulation of polychlorinated biphenyls in steroidgenic tissue of gonads and adrenals in Japanese quail.

Female quail exhibited a high uptake of PCB in the yolk of growing follicles, in the thecal gland cells and the medullary interstitial tissue of the ovary and in the postovulatory and atretic follicles. Uptake in the shell gland was low. An elimination study of four days indicated that the major part of PCB is excreted via the eggs. Male quails showed a very low uptake of PCB in the testes and no accumulation was in the interstitium. The uptake in the fat, liver, and adrenals was similar to that in the females.

Ovarian cycle and reproductive dynamics in the female adder, Vipera berus (Reptilia, Viperidae)

AbstractStudies of reproductive organs, fat body and liver in relation to different activity periods were made to describe the breeding biology of the female adder, Vipera berus, in SW Sweden. The female adder is a biennial breeder. Vitellogenesis and formation of preovulatory follicles start in autumn the non-reproductive year and continue to the end of May the following spring when ovulation takes place. Copulation precedes ovulation and sperm is found in uterus a month before ovulation. Primary oocytes were seen after ovulation in the reproductive year. Atresia were seen more frequently during reproductive years and in all classes of follicles. Clutch size (X=8.8) had a linear increase with female body size and juveniles were born in early August. Thecal gland cells increased in number and the epithelium of the uterus became hypertrophied late in the non-reproductive year and early in the reproductive year. The weight of the ovary, fat body and liver went through a cyclic pattern with the highest peak in the reproductive spring. Fat body and liver weights were lowest at the end of the gestation period. Feeding periods, fat mobilization, reproductive effort, endocrine ectivity and adaptive value of the biennial reproduction are discussed. The adaptation to short season habitats is stressed.

Studies of the fine structure of ovarian interstitial tissue. 7. The postnatal evolution of the thecal gland in the domestic fowl.

Studies of the fine structure of ovarian interstitial tissue. 7. The postnatal evolution of the thecal gland in the domestic fowl.

Studies of the fine structure of ovarian interstitial tissue. 4. Effects of steroids on the thecal gland of the domestic fowl.

The fine structure of ovarian steroid-producing cells of the domestic fowl as seen after administration of steroids is described. Diaethylstilboestrol, estradiol and hydroxyprogesterone were given as intramuscular injections for a 28-days period. The main cytoplasmic changes of the steroid-producing cells were an increase in the number and the size of lipid droplets due to a possible expansion of the endoplasmic reticulum and a confluence of the smooth endoplasmic reticulum and the lipid droplets. The mitochondria became paler, markedly reduced in size and number, and contained less cristae. The Golgi apparatus became smaller and tended to disappear. The most prominent nuclear changes were irregular outline of the nuclear membrane, shrinkage of the nucleus, formation of pseudo-inclusions, decreased number of nuclear bodies with a tendency to vacuolization and small nucleoli. These alterations have never been demonstrated in ovarian steroid-producing cells before, and they are consistent with atrophic changes observed in steroid-producing cells in other organs. The present study substantiates the view that the thecal gland must be concerned with endocrine function. The possible functions of the different cell types of the thecal gland are discussed.

CYCLIC CHANGES IN INTERSTITIAL GLAND TISSUE OF THE HUMAN OVARY.

AbstractThree distinct types of gland cells occur in adult human ovaries and those of other mammals. These are: (1) Interstitial gland cells formed from the theca interna cells of degenerating (atretic) follicles, hence present from infancy to old age; (2) Thecal gland cells formed from the theca interna cells of ripening follicles, hence present only in individuals that are sexually mature or nearly so, and in these only at or near the time of ovulation; (3) Luteal cells formed from the granulosa cells of ovulated follicles and from the undifferentiated stroma cells surrounding these, and in certain species also from the same sources in relation to atretic follicles. These latter are the so‐called accessory corpora lutea. Primary and accessory corpora lutea are present normally only after ovulation occurs and appear to function for a relatively short time unless pregnancy ensues. In certain species other types of gland cells occur in the ovary and mesovarium; these include the paraluteal cells of the human ovary. Paraluteal cells are not persistent thecal gland cells, but are differentiated from surrounding stroma after the thecal gland disappears. They are probably intermediate stages in the differentiation of luteal cells from stroma cells. Planimetric measurements and computations made from serial sections of human ovaries indicate that in non‐pregnancy and early pregnancy the volume of interstitial gland tissue is less than 1% of the total ovarian volume. However, in the last trimester of gestation, the relative amount of interstitial gland tissue increases rapidly to roughly from 4% to 6% of the total ovarian volume. The largest amount in our series was 5.6%. Luteal gland tissue at the height of its development in the first trimester of gestation reached 31% of the total ovarian volume. In human ovaries the cells of the interstitial gland tissue of late pregnancy seem to be consistently larger and to have a more finely granular cytoplasm than those of early pregnancy or nonpregnancy. The literature shows that mammalian interstitial gland cells of comparable origin to the human cells discussed in this paper have the following characteristics which are known to be indicative of steroid secretors: Numerous birefringent, acetone soluble, autofluorescent granules which react with sulphuric acid and are Schultz and Schiff positive; mitochondria with anastomosing tubular cristae; and smooth tubular endoplasmic reticulum. Physiological studies so far reported have indicated possible estrogen, androgen, and progesterone production by interstitial gland cells, but all of the evidence is too scanty, indirect, and at times contradictory to be convincing. Since interstitial gland cells are present from birth to old age, and show cycles of abundance and differentiation correlated with the reproductive age and cycles, they may prove to be the most important ovarian gland cells when their function is fully understood.

The Origin and Fate of Polyovular Follicles in the Striped Skunk

Polyovular follicles develop from primary sex cords in the ovarian medulla of the juvenile striped skunk, Mephitis mephitis . These PF are homologous with the seminiferous tubules of the male. The PF degenerate during the first summer after birth in the young skunk. The ova may degenerate without degeneration of the follicular granulosa cells which remain as anovular medullary cords. When the entire follicle degenerates, a thecal interstitial gland forms and contributes to the mass of medullary interstitial tissue. PF may be induced to ovulate by injections of exogenous gonadotropins but it appears that in the untreated animal degeneration typically occurs rather than ovulation.

Site of production of oestrogen in rat ovary as studied in micro-transplants.

SUMMARYThe present paper is concerned with an investigation on the site of production of oestrogen in the rat ovary by a method designed to yield more direct evidence than hitherto available. A dissection technique was devised permitting isolation of small cell aggregates from the rat ovary containing only one endocrine cell system. Such cell systems alone or in certain combinations were auto‐transplanted to the anterior chamber of the eye of spayed animals, a contiguous vaginal autotransplant serving as an indicator of the oestrogenic activity of the ovarian grafts. The specificity of this indicator system to oestrogen is discussed. As to the ovarian grafts, only in exceptional cases did they produce systemic hormonal effects, and interference by oestrogenic substances from other sources or by metabolites from steroids released in the grafts was excluded by the appearance of the vagina in situ and a control vaginal transplant in the other eye. The following isolated cell systems were transplanted: interstitial cells, theca interna cells, corpus luteum cells and granulosa cells. All of these cell types were able to survive when grafted. In spite of the complex topography of the rat ovary, it proved possible to secure a certain number of grafts consisting of interstitial cells only or of theca interna cells only. Uncontaminated grafts of granulosa cells and corpus luteum cells could be readily obtained. The dissection technique thus provides a tool for studying ovarian tumours experimentally induced in grafts originally containing only one type of endocrine cells. The transplanted granulosa cells were luteinised and formed cell aggregates of the same histological structure as the normal corpus luteum. The following combinations of cell systems were studied: interstitial cells + corpus luteum cells and theca interna cells + granulosa cells or corpus luteum cells. Secretion of oestrogen was never recorded in transplants of the pure cell systems but only in transplants containing theca interna cells or interstitial cells combined with granulosa cells or corpus luteum cells. The validity of these results is discussed and it is excluded that errors in the experimental method might have caused the negative results with the isolated cell systems. Isolated follicles were not transplanted, but the material permitted an indirect analysis of the oestrogen‐producing capacity of follicles in different developmental stages, showing that this probably arises with the development of the theca interna gland cells.It was found that a single follicle with few theca interna cells could produce a local oestrogenic effect on the indicator epithelium, while a single follicle of preovulatory size and well‐developed thecal gland was able to produce full oestrous reaction of the vagina and uterus in situ. It is concluded from these results that the production of oestrogen is dependant on an interplay between theca interna gland cells or interstitial cells and corpus luteum cells or granulosa cells. The primary source of oestrogen in the ovary is discussed against the background of the literature and the present findings. It is concluded that the theca interna gland cells and the interstitial gland cells most probably constitute the oestrogen‐producing system in the ovary but that these cells are functionally dependent on the system granulosa‐corpus luteum cells. The possibility of intra‐ovarian mechanisms operating in both directions between the two principal cell‐systems — the oestrogen‐ and the progestin‐producing — is discussed.

The thecal gland in the guinea pig ovary

The thecal gland in the guinea pig ovary

The thecal gland and its relation to the reproductive cycle. A study of the cyclic changes in the ovary of the pocket gopher, Geomys bursarius (Shaw)

The thecal gland and its relation to the reproductive cycle. A study of the cyclic changes in the ovary of the pocket gopher, Geomys bursarius (Shaw)