Chicken Gonads Research Articles

Chick gonad differentiation following excision of primordial germ cells

The differentiation of embryonic chick gonads lacking germ cells was compared to that of normal chick gonads to determine whether the somatic elements of sterile avian gonads will undergo normal sexual differentiation. Primordial germ cells were removed by surgical excision of anterior germinal crescent from early embryos, Hamburger and Hamilton stages 6–11. Surgically treated and control embryos were sacrificed at 6, 15, and 20 days of incubation, and their gonads were studied histologically. Analysis of differentiation was based on morphological criteria at the cellular, tissue, and organ levels. In both male and female embryos, the somatic elements of the gonads differentiated normally in the absence of germ cells. The significance of these results for understanding the controls of differentiation of both the somatic gonad and the germ cells in birds is discussed and correlated with similar results in mammals.

42. Influence of various factors on embryonic chick gonad steroid hormone production during organ culture

42. Influence of various factors on embryonic chick gonad steroid hormone production during organ culture

Steroidal control of plasma luteiyizing hormone, comb growth and sexual behaviour in male chicks.

Laboratoire de Biochimie et Laboratoire de Radioimmunologie, Université de Liège, 17 Place Delcour, B-4020 Liège, Belgium (Received 31 October 1977) It is well known that the concentration of luteinizing hormone (LH) in the plasma is higher in male than in female chickens (Sharp, 1975) and quail (Nicholls, Scanes & Follett, 1973), probably as a result of greater steroid feedback in the female birds (Davies, 1976). Guichard, Cédard, Mignot, Scheib & Haffen (1977) have shown that embryonic female chick gonads secrete at least ten times more oestradiol than gonads from embryonic male chicks. We have therefore investigated the relative effectiveness of androgens and oestrogens in the control of the level of LH in the male chick and whether non-aromatizable 5α-reduced androgens could depress this level, as has recently been shown in the adult quail (Massa, Davies & James, 1978). Nine groups of between three and seven 1-day-old male chicks were injected

Fine structure of prefollicular and developing germ cells in the male and female left embryonic chick gonads in vitro with and without androgenic steroids

Fine structure of prefollicular and developing germ cells in the male and female left embryonic chick gonads in vitro with and without androgenic steroids

Radioimmunoassay of steroid hormones produced by embryonic chick gonads during organ culture

Gonads from 7 1 2 -18 days embryos were cultured on synthetic medium during 24 h. Radioimmunoassays after ether extraction of the media and of the homogenized organs, allowed quantitative determination of the amount and type of secreted steroids. Progesterone, dehydroepiandrosterone, estrone and estradiol-17β were assayed directly with specific antisera. Testosterone and dihydrotestosterone were previously separated by celite column chromatography. The sum of the steroids present in the explants and in their corresponding media were always higher than the hormone content of the gonads before culture, confirming a steroid production during the explantation. A sexual difference was observed: estrogens were mainly secreted by ovaries and very little estradiol-17β was produced by testes, which secrete more testosterone. At various developmental stages it seems that a 5α-reductase allowed, mainly in the embryonic testes, the formation of DHT.

Evolution of the lining bodies in the embryonic chick gonad

ABSTRACT Gonads from White Leghorn chick embryo of various ages ranging from 4 to 10 days of incubation, were fixed in half-strength Karnovsky’s fixative, osmicated and embedded in Araldite. Thin sections were stained with uranyl acetate and lead citrate. Our observations were especially concentrated on the germinal epithelium. Two cytological characteristics not previously described in embryonic chick gonads were observed:A network of fine microfilaments was present in the somatic cells of the germinal epithelium. These microfilaments were especially concentrated in the apical pole of these cells and appeared to be more numerous in 5- and 6-day gonads. Since similar microfilaments have been described in other embryonic epithelia in which growth of glands or cords is taking place, their presence in the embryonic gonad may be related to the formation of sex cords.Lining bodies, organelles which are characteristic of follicular cells in the adult ovary, were found in the embryonic gonads of both sexes. They first appeared in some of the 5-day embryos and were present thereafter in all 6-day left gonads, in all left ovaries and in those left testes in which regression of the germinal epithelium had not been completed. Lining bodies were never observed in right germinal epithelia. It is classically accepted that follicular cells of the adult originate from the somatic cells of the germinal epithelium. The presence of lining bodies in the epithelial cells of young embryos appears to indicate that, despite the fact that follicles are not formed until after hatching, follicular cells initiate their differentiation much earlier. The fact that this differentiation is also present in gonads of male embryos can be interpreted in the light of current theories on sex differentiation which assume the bisexuality of embryonic gonads.Short cytoplasmic processes, representatives of a merocrine secretory process, have been described by other authors in the germinal epithelium of young embryos. We confirmed these observations and found, in addition, that these processes were smaller, both in size and number, in the right gonads. This fact, together with the previously mentioned absence of lining bodies in right gonads, appears to be the expression, at the ultrastructural level, of the well known asymmetry of the avian embryonic gonads.

Submicroscopical observations on the differentiation of chick gonads

ABSTRACT The role of hormones in gonadal differentiation has not been fully elucidated. One of the main problems consists in determining the exact moment in which steroid synthesis begins. If, as has been claimed, sex hormones act as organizers and are responsible for the morphological changes which characterize gonadal differentiation, then they should appear before these changes take place.

DELTA-5-3-BETA-HYDROXYSTEROID DEHYDROGENASE IN DIFFERENTIATING CHICK GONADS.

A histochemical technique for 3β-hydroxysteroid-dehydrogenase was applied to chick embryonic gonads between the seventh and fourteenth day of incubation. Up to the sixth and seventh day, the undifferentiated gonads gave negative reactions. Eleven out of twenty-eight ovaries of eight days showed some reaction and all ovaries over that age a stronger reaction, which was localized in isolated groups of cells distributed between medullary lacunae. Testes were negative before the tenth day, showing after that time an atypical and possibly unspecific reaction consisting of a diffuse purple stain of testicular cords. Adrenal glands were positive at all ages. The interpretation of these facts is discussed in relation to the production of steroid hormones by the embryonic gonads and their possible role in sex differentiation.

Modification Expérimentale du Développement de l’Ovaire de Souris sous l’influence du Testicule Embryonnaire de Poulet

ABSTRACT Mouse ovaries from foetuses 12–21 days of gestation were explanted in vitro in association with gonads of 6–10 days chick embryos. After 2-6 days of culture, the expiants were grafted into the coelom of young chick embryos. Grafts were removed when hosts were 12–19 days old (Plate 1, Figs. 1 and 2). In associations of mouse and chick ovaries, the two organs fused together forming chimeric organs (Plate 1, Fig. 3). The mouse gonad, containing numerous oocytes and primary follicles, lay in the medullary part of the chick gonad (Plates 1 and 2, Figs. 3–7). In associations of mouse ovary with chick testis, the development of the mouse ovary was inhibited (Plates 2 and 3, Figs. 8–14). Cortical structures were very sensitive to the testicular influence; and oocytes degenerated or failed to develop. Follicles when present had an abnormal appearance (Plate 2, Fig. 9). The degree of inhibition depended on the type of association and the age of the gonad when transplanted (Plate 2, Figs. 9 and 10). Some ‘medullary’ structures persisted in these inhibited ovaries. The rete ovarii, which looks like winding cords, was well developed and penetrated into the chick tissue where it established direct connection with testicular tubules (Plate 3, Fig. 16). In some expiants, in the vicinity of the rete, cords of testicular aspect which sometimes contained oocytes or degenerating follicles were observed (Plate 3, Fig. 13). These results demonstrate that mouse ovary associated with chick ovary can develop when transplanted to chick embryos. Oogenesis takes place, the oocytes grow and primary follicles develop.

HISTOCHEMICAL DEMONSTRATION OF CHOLESTEROL IN EMBRYONIC CHICK GONADS DIFFERENTIATED "IN VITRO".

Gonads from six and seven day chick embryos were cultured with the common watch-glass technique using natural and synthetic media. The presence of cholesterol in these gonads was determined with the digitonine histochemical technique. A large number of the explanted gonads showed positive reactions with the same localization as previously observed in gonads differentiating “in vivo”. The possible interpretation of these results is discussed.

Histochemical demonstration of cholesterol in differentiating chick gonads

Histochemical reactions for lipids (Sudan Black) and for cholesterol (digitonine precipitation) were applied to gonads of chick embryos between seven and twelve days of incubation.

Effect of grouping on adrenals and gonads of chickens.

Abstract 1. 1. Adrenals and thyroids of birds kept in groups of six were significantly heavier than the adrenals and thyroids of heterosexual pairs kept at the same density. 2. 2. After sexual maturity the adrenal weights of cocks correlated reciprocally with social rank. 3. 3. Adrenal stimulation, as measured by lipid depletion, correlated well with the amount of social interaction within each group. 4. 4. Subordinate grouped cocks were found to have a slower testes weight gain, delayed onset of spermatogenesis, and degenerative changes in the testes in comparison to paired and grouped dominant males.

Experimentally Induced Proliferation of the Rudimentary Gonad of an Intact Domestic Fowl

IT is well known that the right female gonad of the domestic fowl ceases to grow about the ninth day of incubation and that it always hypertrophies following sinistral ovariectomy. I have shown1 that œstrogen could act in vivo as the inhibitor of rudiment growth. In view of the anti-œstrogenic effect of 17 α-ethyl-19-nortestosterone (‘Nilevar’, Searle) upon the chicken's oviduct2, the effect of this substance upon the rudimentary chicken gonad was investigated. Starting at 60 days of age intact White Leghorn females received 40 subcutaneous injections of ‘Nilevar’. The substance was dissolved in a carrier of 5 per cent benzyl alcohol in corn oil and 0.1 c.c. of solution was injected daily. Experimental procedures were analogous to those outlined in the earlier paper1 and the weights of blotted, fixed (Bouin's fixative) tissue were recorded (Table 1).

Responses of ovaries of immature chickens to avian and mammalian gonadotrophins.

THE bulk of studies on the response of avian gonads to gonadotrophic hormones has been done using hormones of mammalian origin. This work established that gonads of normal adult chickens of both sexes are capable of being stimulated by mammalian gonadotrophms. However, in the domestic chicken, between the ages of one and about 150 days, the gametogenic component of the ovary is almost completely refractory to gonadotrophins of mammalian origin. Thus, injection of crude or purified gonadotrophic substances from sheep, pigs and mares (including pregnant mare’s serum) does not lead to any measurable enlargement of ovarian follicles of prepuberal female chickens. Two alternative explanations for the failure of the prepuberal avian cortex to respond to mammalian hormones can be offered: 1. a physiological or morphological unreadiness of the cortex of the avian ovary, and 2. an endocrine incompleteness of the mammalian hormones used.

Effect of Total Body Irradiation on Rabbit Pituitary as Measured by Gonadotropin Response in Chicks.

SummaryRabbit pituitaries from animals exposed to 750 and 1100 r of total body Cobalt-60 gamma irradiation showed an early suppression of gonadotropin principles as measured by the chick gonad response. The 750 r group showed the depression on the 8th day after irradiation while in the 1100 r group the suppression was evident by day one and was sustained through day 7. After this time the gonadotropin activity in both groups returned to the normal level.

Mating Behavior and the Social Hierarchy in Small Flocks of White Leghorns

Mating Behavior and the Social Hierarchy in Small Flocks of White Leghorns

The specificity of sex, of organization, and of differentiation of embryonic chick gonads as shown by grafting experiments

Journal of Experimental ZoologyVolume 46, Issue 4 p. 409-465 Article The specificity of sex, of organization, and of differentiation of embryonic chick gonads as shown by grafting experiments B. H. Willier, B. H. Willier Hull Zoölogical Laboratory, The University of ChicagoSearch for more papers by this author B. H. Willier, B. H. Willier Hull Zoölogical Laboratory, The University of ChicagoSearch for more papers by this author First published: January 1927 https://doi.org/10.1002/jez.1400460403Citations: 26AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Citing Literature Volume46, Issue4January 1927Pages 409-465 RelatedInformation

The behavior of embryonic chick gonads when transplanted to embryonic chick hosts

Experiments were begun in the spring of 1924 for the purpose of analyzing the sex potentialities of developing chick gonads by transplanting them to the vascular chorio-allantoic membranes of host chick embryos. In these experiments the circulations of the host embryo and the sex graft are related in a manner which is essentially similar to the relations existing between twin embryos in cattle.1 In this analysis several important problems arise. It may be possible to determine first how early in development the sex potencies of the gonads and their laterality are fixed; secondly, whether these original sex potencies may be modified or inverted by transplanting the gonadal primordia during the morphologically indifferent stage to host embryos of opposite sexes; thirdly, the behavior of sexually differentiated right and left ovaries and testes when implanted to male and female host embryos.The method employed was essentially the same as previously reported.2 The Wolffian body with its associated sex gland a...