Do sexual differences in the organization of the brain exist, and if so, why? Are they caused by environment or genetics? In fact, the evidence for sexual dimorphism in the brain is compelling. In many animals, distinct differences between sexes in brain morphology have been found that are believed to be responsible for a number of the observed behavioral differences between the sexes. How do t...

Sex steroids can both modulate and be modulated by behavior, and their actions are mediated by complex interactions among multiple hormone sources and targets. While gonadal steroids delivered via circulation can affect behavior, changes in local brain steroid synthesis also can modulate behavior. The relative steroid load across different tissues and the association of these levels with rates ...

Hormone-dependent sociosexual behaviors of the displaying individual regulate the abundance of estrogen receptor- and progesterone receptor-mRNA in sex steroid hormone-concentrating brain areas of the partner. This effect of behavior on gene expression in the brain is independent of the gonads.

Incubation temperature during embryonic development determines gonadal sex in the leopard gecko (Eublepharis macularius). Incubation temperature and gonadal sex jointly influence the display of sexual and agonistic behavior in adult leopard geckos. These differences in adult behavior are organized prior to sexual maturity, and it is plausible that post-natal hormones influence neural and behavi...

-1 . Biosynthesis of steroid hormones from radioactive progesterone, 17c~-hydroxyprogesterone, androst-4-ene-3,17-dione and testosterone by the adrenals of male and female Rhesus monkeys was studied. 2. On a comparative basis the adrenals from the female monkeys yielded a higher ratio of estrogens to androst-4-ene-3,17-dione and/or testosterone among the biosynthetic products. 3. Probably due t...

Sex, age and sexual maturation are key biological parameters for aspects of life history and are fundamental information for assessing demographic changes and the reproductive viability and performance of natural populations under exploitation pressures or in response to environmental influences. Much of the information available on the reproductive condition, length at sexual maturity and sex ...

Gonadal steroid hormones have been shown to influence adult neurogenesis in addition to their well-defined role in regulating social behavior. Adult neurogenesis consists of several processes including cell proliferation, which can be studied via 5-bromo-2'-deoxyuridine (BrdU) labeling. In a previous study we found that social stimulation altered both cell proliferation and levels of circulatin...

Decline in circulating sex steroid hormones accompanies several age-associated pathologies which may influence human healthspan. Mitochondria play important roles in biosynthesis of sex steroid hormones, and these hormones can also regulate mitochondrial function. Understanding the cross talk between mitochondria and sex steroid hormones may provide insights into the pathologies associated with...

Sex, stimulus material and attention condition have previously been related to global advantage (faster responses to global targets than to local targets), as well as lateralization during global-local processing. It is presumed that the lateralization of brain functions is either related to the inhibitory influence of the dominant on the non-dominant hemisphere or reduced excitation between he...

To understand the rationale behind recommended control programs for liver flukes in cattle, the economic impact and the complex life cycle of Fasciola hepatica need to be appreciated. Fluke-infected cattle rarely demonstrate clinical disease, but subclinical impairment of feed efficiency, growth, and fertility can have an important impact on productivity. Although the precise benefit from contr...