Metabolic conversion of oestrogen phenolic groups may create conditions of oxidative stress accompanied by damage of cellular macromolecules including DNA. The aim of this investigation was to evaluate the cell cycle kinetics and possible cytogenetic changes in cultured human peripheral blood lymphocytes exposed to seven experimental concentrations of 17 -oestradiol (range 10 M to 10 M). Cell c...

Understanding the many factors that underlie phenotypic variation is of profound importance to evolutionary biologists. The embryonic endocrine environment is one such factor that has received much attention. In placental amniotes, the dynamic interaction of maternal and embryonic steroid production and metabolism is critical to regulating the endocrine environment. Less is known about how embr...

BACKGROUND Llamas (Lama glama) are induced ovulators and the process of ovulation depends on dominant follicular size. In addition, a close relationship between behavioural estrus and ovulation is not registered in llamas. Therefore, the exogenous control of follicular development with hormones aims to predict the optimal time to mate. Oestradiol-17beta (E2) and its esters are currently used in...

Radioimmunoassays for five oestrogen metabolites in urine are described; they are oestrone 3-glucuronide, oestradiol 3-glucuronide, oestradiol 17 beta-glucuronide, oestriol 3-glucuronide and oestriol 16 alpha-glucuronide. These assays have proved accurate and reliable and can be performed rapidly; they have been carried out directly in diluted menstrual cycle urine and pregnancy urine. No sampl...

An early response to the administration of oestradiol-17beta to immature rats is the synthesis of uterine RNA of very high-molecular-weight. This RNA is shown to be heterogeneous nuclear RNA. Increased precursor incorporation into the heterogeneous nRNA is not confined to entities of precise molecular weight but appears to involve much of the size range of the species. These findings are discus...

Data regarding the effects of progesterone and a progestagen on human normal breast epithelial cell proliferation and apoptosis are presented here. In postmenopausal women, adding progesterone to percutaneously administrated oestradiol significantly reduces the proliferation induced by oestradiol. In vitro and in premenopausal women, stopping the administration of nomegestrol acetate triggers a...

The changes in egg production, in broodiness index and in plasma concentrations of LH, prolactin, oestradiol and progesterone were monitored throughout the first period of laying in turkey hens. The hens were subsequently classified according to their ability to express broodiness (33%) and their laying persistency; 25% were out-of-lay by the end of the experiment. A high percentage (67%) of th...

The binding of [6,7_3H]oestradiol-17P to subcellular fractions of the hypothalamus and the cerebellum of the rabbit was studied in vitro. Uptake of steroid was higher in hypothalamic nuclei than in cerebellar nuclei. Lower binding was observed in other fractions of both tissues. After dialysis of the fractions, hypothalamic nuclei retained a high percentage of oestradiol whereas cerebellar nucl...

Plasma concentrations of LH, progesterone and oestradiol were measured in 5 cyclic swamp buffaloes. Progesterone levels began to increase after Day 5 (Day 0 = the day of oestrus) and reached a plateau after Day 10. A rapid decrease in progesterone levels occurred during the 5 days before oestrus, followed by a sustained increase in oestradiol concentrations. Basal LH levels decreased towards th...

The influence of neonatal androgenization on behavioural receptivity was tested by treating female voles on the 3rd day of life with testosterone propionate or with the oil vehicle. After treatment in adulthood with urine or with oestradiol benzoate, androgenized voles were less likely than normal females to display behavioural oestrus and were more likely to engage in agonistic behaviour in te...