ESTROGEN RECEPTORS mRNA EXPRESSION IN THE PREHIERARCHICAL OVARIAN FOLLICLES IN THE GROWING CHICKEN AFTER GROWTH HORMONE ADMINISTRATION

Abstract

The previous study revealed that growth hormone (GH) affects steroidogenesis, proliferation and apoptosis in the ovary of the domestic hen. However, the mechanisms of GH action in the chicken ovary have not been fully elucidated. Thus, the current study was conducted to investigate the effect of GH on the mRNA expression of alfa (ERï¡) and beta (ERï¢) estrogen receptors in the prehierarchical follicles of the chicken during puberty by RT-PCR method. The experiment was carried out on sexually immature 10-week-old Hy-Line hens that were injected with recombinant chicken GH (cGH) (experimental group) or vehicle (control group). The ovaries were isolated from birds in 2-weeks intervals from 10 to 16 weeks of age, and at 17 weeks, just after the onset of laying. Subsequently, the stroma, the white and the yellowish follicles were collected from the ovaries. GH significantly elevated the expression of ERï¡ and ERï¢ mRNA in the white follicles of 16- and 17-week-old chickens as well as increased the expression of ERï¢ mRNA in the yellowish follicles after the onset of egg laying. In conclusion, the results of the current study demonstrated that the effect of GH on the expression of both forms of ERs was dependent on the size of follicle and the age of birds. It is suggested that GH via alternation of ERs gene expression in the prehierarchical follicles may participate in the chicken ovary development and functions.