Coturnix

About: Coturnix is a research topic. Over the lifetime, 953 publications have been published within this topic receiving 23305 citations.

Seasonal expression and cellular distribution of star and steroidogenic enzymes in quail testis

Abstract: The quail Coturnix coturnix is a seasonal breeder with a physiological switch on/off of gonadic activity. Photoperiod and temperature are the major environmental factors regulating the spermatogenesis. To more thoroughly comprehend the steroidogenic pathways that govern the seasonal reproductive cycle, we have investigated the localization of StAR protein and steroidogenic enzymes (3β-HSD, 17β-HSD, P450 aromatase, and 5α-Red) as well as androgen and estrogen levels, in the testis of reproductive and nonreproductive quails. We demonstrated that StAR, 3β-HSD, 17β-HSD, P450 aromatase, and 5α-Red were always present in the somatic (Leydig and Sertoli cells) and germ cells (spermatogonia, spermatocytes I and II, spermatids, and spermatozoa). In addition, by western blot analysis, we demonstrated that 17β-HSD, P450 aromatase, and 5α-Red showed the highest expression levels during the reproductive testis compared with nonreproductive one. Accordingly, we also found that during the reproductive phase the highest titres of testosterone, 17β-estradiol, and 5α-dihydrotestosterone are recorded. In conclusion, our findings demonstrated that in C. coturnix: (a) both somatic and germ cells are involved in the local synthesis of sex hormones; (b) 17β-HSD, P450 aromatase, and 5α-Red expressions, as well as testicular androgens and estrogens, increased in reproductive quail testis. This study strongly indicates that the steroidogenic process in quail testis exhibits seasonal changes with the promotion of both androgenic and estrogenic pathways in the reproductive period, suggesting their synergic mechanism in the spermatogenesis regulation.

Selective estrogen receptor alpha activation disrupts sex organ differentiation and induces expression of vitellogenin II and very low-density apolipoprotein II in Japanese quail embryos.

Abstract: The Japanese quail (Coturnix japonica) is a widely used model species for studying the roles of steroid hormones in avian sex differentiation. The aim of the present study was to elucidate the significance of estrogen receptors alpha and beta (ERalpha and ERbeta) in normal sex differentiation of the reproductive organs in the Japanese quail and in xenoestrogen-induced disruption of reproductive organ differentiation. Real-time PCR indicated that ERalpha (ESR1) mRNA is expressed in both right and left gonads and Mullerian ducts (MDs) in both sexes during early morphological differentiation. ERbeta (ESR2) transcripts were also detected in gonads and MDs, but at very low levels. Both receptor subtypes were expressed in the liver and may therefore mediate the expression of estrogen-regulated egg-yolk proteins. Aromatase mRNA was expressed at much higher levels in female than male gonads as early as embryonic day 5, indicating early sex differences in estrogen synthesis. Treatment with the ERalpha-selective agonist propyl pyrazole triol showed that frequently reported xenoestrogen effects, such as ovotestis formation, abnormal MD development, and hepatic expression of egg-yolk proteins, were induced by selective activation of ERalpha. Taken together, our results suggest that activation of ERalpha is crucial for estrogen-dependent sex differentiation of the reproductive organs and that ERalpha mediates xenoestrogen-induced toxicity during reproductive development in birds.

Biochemical characterization of avian T lymphocyte-specific antigens.

Abstract: Sera from rabbits injected with quail thymocytes were absorbed on quail bursal and liver cells. The absorbed sera reacted with avian T but not B lymphocytes in an immunofluorescence assay. Material precipitated by the anti-T antisera from lysates of radioiodinated chicken or quail thymocytes was analyzed by one- and two-dimensional electrophoresis. Of two anti-T cell antisera studied in detail, one reacted mainly with a protein of an apparent molecular weight of 45 000 - 55 000, and the other with a protein of an apparent molecular weight 65 000 - 70 000. These proteins may be homologues of previously described mammalian T lymphocytes-specific antigens.