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The vitamin D3-dependent calcium binding protein, calbindin-D28K (CaBP-D28K), plays an important role in transepithelial calcium translocation. To evaluate its role in chick embryonic calcium metabolism, steady-state levels of CaBP-D28K mRNA in various tissues of the chick embryo were determined by Northern blot and slot blot analyses, and CaBP-D28K(More)
Thirty-four-week-old laying hens received injections of recombinant chicken leptin to assess the role of leptin in avian ovarian function. In the first experiment, the hens (n=60) were divided into three groups: (i). fed ad libitum; (ii). fasted; and (iii). fasted + leptin. Hens were fasted for 5 days and those treated with leptin received 250 microg leptin(More)
The present study was undertaken to examine the effect of recombinant chicken leptin administered to fed ad libitum and feed-restricted immature chickens of a layer strain on ovarian development and the timing of sexual maturity. In the first experiment 11-week-old pullets (77 days of age) fed ad libitum were injected daily with leptin at four dose levels(More)
The aim of the experiment was to study the in vitro effect of 3,3',4,4',5-pentachlorobiphenyl (PCB 126; a coplanar PCB congener) on aryl hydrocarbon receptor (AHR1) and AHR1 nuclear translocator (ARNT1) mRNA expression and the activity of CYP1 family monooxygenases in chicken ovarian follicles. White (1-4 mm) and yellowish (4-8 mm) prehierarchical follicles(More)
The present study was undertaken to examine in vivo the effect of growth hormone (GH) on progesterone and estradiol levels and on cell proliferation and apoptosis in the chicken ovary during sexual maturation. Hy-Line chickens (10 weeks old) were injected three times a week with 200 μg recombinant chicken GH (cGH) per kilogram body weight until sexual(More)
Information concerning the role of growth hormone (GH) in the local regulation of ovarian activity in birds is limited. Therefore, the aim of the present study was to determine whether in the domestic hen GH influences in vitro estradiol secretion by prehierarchical ovarian follicles. Moreover, the interaction between GH and IGF-I on estradiol secretion was(More)
Among the environmental chemicals which disturb endocrine functions, dioxins and polychlorinated biphenyls (PCBs) are known as the most toxic. Numerous studies in mammals revealed that dioxins and PCBs disrupt functions of the uterus, delay implantation and increase embryo loss. The direct effect of these chemicals on the avian oviduct is not known.(More)
The present study was designed to (1) assess the role of triiodothyronine (T(3)) with regard to in vitro steroid hormone secretion by chicken ovarian follicles; (2) determine whether T(3) influences the in vivo function of the pituitary-ovarian axis in the hen; and (3) detect expression of thyroid hormone receptor (TR) mRNA in chicken ovarian follicles. In(More)
The organism of a food-deprived animal is directed toward minimizing energy expenditure and plasma levels of catabolic hormones and glucose are also reduced. Stress, on the other hand, is associated with enhancement of metabolic processes, elevated plasma catabolic hormones, and higher glucose levels. The question arises as to whether food deprivation may(More)