Lymphoid aggregates in gonads of embryos, hatchlings, and young of turtles with temperature-dependent sex determination.

Cellular infiltrations forming lymphoid-like aggregates were previously observed in gonads of two turtle species exhibiting temperature-dependent sex determination (TSD): at hatching in Chelydra serpentina; at and after hatching in Emys orbicularis. We show here that such aggregates are also present in gonads of Testudo graeca by the end of embryonic development, suggesting that their occurrence is general in turtles. Since in C.

Degree of sex reversal as related to plasma steroid levels in genetic female chickens (Gallus domesticus) treated with Fadrozole.

The objectives of this work were to determine whether or not plasma levels of testosterone and estradiol reflect the various grades of sex reversal in genetic female chickens treated with Fadrozole (CGS 16949 A), a nonsteroidal aromatase inhibitor, and whether gonadal aromatase activity and plasma levels of testosterone and estradiol in treated females can or not be modified by post-hatch treatments with Fadrozole or Fadrozole + testosterone. Eggs were injected with 1 mg Fadrozole on day 4 of incubation. In females having developed sex-reversed gonads, endocrine parameters (estradiol and testosterone) at and after 13 weeks of age were indicative of the degree of sex reversal, with, for example, sex-reversed females with two testes having the highest levels of testosterone and the lowest levels of estradiol.

Sex reversal and aromatase in chicken.

Aromatase inhibitors administered before sexual differentiation of the gonads can induce sex reversal in female chickens. To analyze the process of sex reversal, we have followed for several months the changes induced by Fadrozole, a nonsteroidal aromatase inhibitor, in gonadal aromatase activity and in morphology and structure of the female genital system. Fadrozole was injected into eggs on day four of incubation, and its effects were examined during the embryonic development and for eight months after hatching.

Expression of AMH, SF1, and SOX9 in gonads of genetic female chickens during sex reversal induced by an aromatase inhibitor.

Aromatase inhibitors administered prior to histological signs of gonadal sex differentiation can induce sex reversal of genetic female chickens. Under the effects of Fadrozole (CGS 16949A), a nonsteroidal aromatase inhibitor, the right gonad generally becomes a testis, and the left gonad a testis or an ovotestis. We have compared the expression pattern of the genes encoding AMH (the anti-Müllerian hormone), SF1 (steroidogenic factor 1), and SOX9 (a transcription factor related to SRY) in these sex-reversed gonads with that in control testes and ovaries, using in situ hybridization with riboprobes on gonadal sections.

Sex reversal and aromatase in the European pond turtle: treatment with letrozole after the thermosensitive period for sex determination.

In the European pond turtle (Emys orbicularis), gonadal sex differentiation is temperature-dependent. The temperature sensitive period (TSP) of gonadogenesis lies between stages 16 and 22 of embryonic development. Previous studies have shown that embryos incubated at 30 degrees C, a temperature yielding 100% phenotypic females, can be sex reversed by treatments with an aromatase inhibitor administered during TSP or even somewhat after TSP (as of stage 22+).

Temperature-dependent sex determination and gonadal differentiation in reptiles.

In many reptile species, sexual differentiation of gonads is sensitive to temperature (temperature-dependent sex determination, TSD) during a critical period of embryonic development (thermosensitive period, TSP). Experiments carried out with different models including turtles, crocodilians and lizards have demonstrated the implication of estrogens and the key role played by aromatase (the enzyme complex that converts androgens to estrogens) in ovary differentiation during TSP and in maintenance of the ovarian structure after TSP. In some of these experiments, the occurrence of various degrees of gonadal intersexuality is related to weak differences in aromatase activity, suggesting subtle regulations of the aromatase gene at the transcription level.

Temperature-dependent sex determination and gonadal differentiation in reptiles.

In many reptile species, sexual differentiation of gonads is sensitive to temperature during a critical period of embryonic development (thermosensitive period, TSP). Experiments carried out with different models among which turtles, crocodilians and lizards have demonstrated the implication of estrogens and the key role played by aromatase (the enzyme complex that converts androgens to estrogens) in ovary differentiation during TSP and in maintenance of the ovarian structure after TSP. In some of these experiments, the occurrence of various degrees of gonadal intersexuality is related to weak differences in aromatase activity, suggesting subtle regulations of the aromatase gene at the transcription level.

Sexual differentiation of gonads as a function of temperature in the turtle Emys orbicularis: endocrine function, intersexuality and growth.

Emys orbicularis is a freshwater turtle with temperature-dependent sex determination. Estrogens play a major role in gonadal differentiation; when they are produced at high levels during the thermosensitive period (TSP), ovaries differentiate; when their synthesis is very low, testes differentiate. Estrogens are synthesized from androgens through the activity of aromatase.

The ovary retains male potential after the thermosensitive period for sex determination in the turtle Emys orbicularis.

Emys orbicularis is a turtle with temperature-dependent sex determination. The thermosensitive period (TSP) lies between embryonic stages 16 and 22. Gonadal differentiation begins during this period involving oestrogens.

Endocrine sex reversal of gonads by the aromatase inhibitor Letrozole (CGS 20267) in Emys orbicularis, a turtle with temperature-dependent sex determination.

In embryos of Emys orbicularis, the sexual differentiation of gonads is influenced by the incubation temperature of eggs. Estrogens administered during the thermosensitive period result in the feminization of gonads at 25 degrees (male-producing temperature), whereas an antiestrogen or aromatase inhibitors masculinize the gonads at 30 degrees (female-producing temperature). The nonsteroidal aromatase inhibitor Letrozole induces gonads with different degrees of masculinization, from ovary-like to testis-like.

A protein from Daudi cell line conditioned medium induces ovarian dysgenesis in Drosophila melanogaster.

From a medium in which Daudi cells had been grown, we isolated by HPLC a protein that caused ovarian abnormalities in adult females of Drosophila melanogaster when injected into preblastoderm embryos. This protein, whose apparent M(r) is between 30,000 and 50,000, was found to be a moderately polar compound which is heat stable and whose activity is destroyed by acidification. The protein is characteristic of medium conditioned from Daudi cells.

Abnormal ovarian morphogenesis in Drosophila melanogaster after injection of embryos with conditioned media from the Daudi cell line.

Drosophila melanogaster embryos were injected before the blastoderm stage with conditioned media from several male Burkitt's lymphoma human cell lines and the Daudi cell line. Such injections do not have any effect on the male genital apparatus or on the female tract. The Daudi conditioned medium modifies the ovarian morphogenesis of the flies and the rudimentary ovaries obtained look like nymphal gonads.

[Organogenesis of sterile ovaries and testes after cauterization of pole cells of colorado beetle embryos (Leptinotarsa decemlineata SAY)].

Cauterization of pole cells in embryos of the Colorado beetle does not prevent organogenesis of the gonads. So, pole cells do not govern to the differentiation of the gonadal mesoderm (this latter is limited to abdominal segments 6, 7 and 8). Moreover, this mesoderm develops into testis or ovary even without any innitial germ cells.