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The rapid activation of stress-responsive neuroendocrine systems is a basic reaction of animals to perturbations in their environment. One well-established response is that of the hypothalamo-pituitary-adrenal (HPA) axis. In rats, corticosterone is the major adrenal steroid secreted and is released in direct response to adrenocorticotropin (ACTH) secreted(More)
Estrogens are reported to have both anxiogenic and anxiolytic properties. This dichotomous neurobiological response to estrogens may be mediated by the existence of two distinct estrogen receptor (ER) systems, ERalpha and ERbeta. In brain, ERalpha plays a critical role in regulating reproductive neuroendocrine function, whereas ERbeta may be more important(More)
To examine mechanisms responsible for sex differences in hypothalamo-pituitary-adrenal (HPA) axis responsiveness to stress, we studied the role of androgens in the regulation of the adrenocorticotropin (ACTH) and corticosterone (CORT) responses to foot shock and novelty stressors in gonadectomized (GDX) or intact male F344 rats. Foot shock or exposure to a(More)
The actions of androgens in both peripheral and central tissues are linked in part to their ability to specifically bind and activate androgen receptors (ARs). ARs have been well studied in the rat hypothalamus and peripheral reproductive tissues, where they are directly involved in endocrine feedback mechanisms and reproduction. Previous studies revealed(More)
During development, estrogen has a variety of effects on morphological and electrophysiological properties of hippocampal neurons. Brain-derived neurotrophic factor (BDNF) also plays an important role in the survival and differentiation of neurons during development. We examined the effects of gonadectomy with and without estrogen replacement on the mRNA(More)
Estrogens have been shown to have positive and negative effects on anxiety and depressive-like behaviors, perhaps explained by the existence of two distinct estrogen receptor (ER) systems, ERalpha and ERbeta. The ERbeta agonist, diarylpropionitrile (DPN) has been shown to have anxiolytic properties in rats. DPN exists as a racemic mixture of two(More)
Pulsatile secretion of gonadotropin releasing hormone in mammals is thought to depend on repetitive and prolonged bursts of action potentials in specific neuroendocrine cells. We have previously described episodes of electrical activity in isolated gonadotropin releasing hormone neurons, but the intrinsic mechanisms underlying the generation of spike bursts(More)
BACKGROUND The discovery of equol in human urine more than 2 decades ago and the finding that it is bacterially derived from daidzin, an isoflavone abundant in soy foods, led to the current nutritional interest in soy foods. Equol, unlike the soy isoflavones daidzein or genistein, has a chiral center and therefore can occur as 2 distinct diastereoisomers.(More)
The complexity of gonadal steroid hormone actions is reflected in their broad and diverse effects on a host of integrated systems including reproductive physiology, sexual behavior, stress responses, immune function, cognition, and neural protection. Understanding the specific contributions of androgens and estrogens in neurons that mediate these important(More)
The hypothalamo-pituitary-adrenal (HPA) axis represents a complex neuroendocrine feedback loop controlling the secretion of adrenal glucocorticoid hormones. Central to its function is the paraventricular nucleus of the hypothalamus (PVN) where neurons expressing corticotropin releasing factor reside. These HPA motor neurons are a primary site of integration(More)