Many nontropical rodent species display seasonal changes in both physiology and behavior that occur primarily in response to changes in photoperiod. Short-day reductions in reproduction are due, in part, to reductions in gonadal steroid hormones. In addition, gonadal steroids, primarily testosterone (T), have been implicated in aggression in many mammalian species. Some species, however, displa...

Sex steroids, also known as gonadal steroids, are oxidized with hydroxylation by cytochrome P450, glucuronidation by UDP-glucuronosyltransferase, sulfation by sulfotransferase, andO-methylation by catechol O-methyltransferase. Thus, it is important to determine the process by which inflammation influences metabolism of gonadal hormones. Therefore, we investigated the mechanism of metabolic enzy...

Syferkuil Dam is situated 8 km NW of the University of the North and comprises a series of eight interconnected rectangular dams, having cement sides and mud bottoms. Throughout the experimental period, male and female adult specimens of the mouthbrooding tilapia, Oreochromis mossambicus were collected for further analysis. Aspects of the reproductive physiology of O. mossambicus that were inve...

The role of hormones in gonadal differentiation has not been fully elucidated. One of the main problems consists in determining the exact moment in which steroid synthesis begins. If, as has been claimed, sex hormones act as organizers and are responsible for the morphological changes which characterize gonadal differentiation, then they should appear before these changes take place. Although t...

The search for a definitive gender bias in Alzheimer's disease has resulted in a multitude of epidemiological findings that point to a higher prevalence and incidence of Alzheimer's disease in women. Due to this reported predisposition of women to Alzheimer's disease, the sex steroid estrogen has become the primary focus of research in this field, however, inconclusive data regarding estrogen r...

Steroid hormones of gonadal origin act on the neonatal brain to produce sex differences that underlie adult reproductive physiology and behavior. Neuronal sex differences occur on a variety of levels, including differences in regional volume and/or cell number, morphology, physiology, molecular signaling, and gene expression. In the rodent, many of these sex differences are determined by steroi...

In 1936, Eugen Steinach and colleagues published a work that brought steroid biochemistry to the study of sexual behavior and, using synthetic androgens and estrogens, foreshadowed by an astonishing 4 decades the discovery of the central role of estrogen in the sexual behavior of male rats. We offer an English translation of that paper, accompanied by historical commentary that presents Steinac...

OADES, R. D. Search and attention: Interactions of the hippocampal-septal axis, adrenocortical and gonadal hormones. NEUROSCI. BIOBEHAV. REV. 3(1) 31--48, 1979.--The phenomenon of attention is treated in terms of the ability to select some sensory input channels over others by the central nervous system for further processing and behavioural organisation. Studies of birds and mammals are review...

Erectile function is a complex neurovascular process that depends on the health of the central and peripheral nervous systems and the vasculature. Thus, signaling from the central nervous system (brain) to the peripheral nervous system (penis) is critical and is modulated by a set of complex interactions that depend on cerebral and vascular circulation. The cerebral and peripheral vasculatures ...