The adrenal cortex acts by the elaboration of a series of "hormones which include among their functions the regulation of the electrolyte balance; carbohydrate, fat and protein metabolism; the development of the secondary sexual characteristics; and possibly the development of the gonads themselves. Although the action of many of these hormones is regulated by the pituitary, the latter gland ha...

1. The presence of siblings might have long-lasting fitness consequences because they influence the early environment in which an animal develops. Several studies under laboratory conditions have shown long-lasting consequences from the presence of male siblings in utero on morphology and life-history traits. However, in wild animals, such effects of litter sex composition are unexplored. 2. We...

Sexually dimorphic phenotypes arise largely from sex-specific gene expression, which has mainly been characterized in sexually naïve adults. However, we expect sexual dimorphism in transcription to be dynamic and dependent on factors such as reproductive status. Mating induces many behavioral and physiological changes distinct to each sex and is therefore expected to activate regulatory changes...

Appropriate displays of aggression rely on the ability to recognize potential competitors. As in most species, Drosophila males fight with other males and do not attack females. In insects, sex recognition is strongly dependent on chemosensory communication, mediated by cuticular hydrocarbons acting as pheromones. While the roles of chemical and other sensory cues in stimulating male to female ...

In autism, heterogeneity is the rule rather than the exception. One obvious source of heterogeneity is biological sex. Since autism was first recognized, males with autism have disproportionately skewed research. Females with autism have thus been relatively overlooked, and have generally been assumed to have the same underlying neurobiology as males with autism. Growing evidence, however, sugg...

Androgens play a number of important physiological roles in the human. In the male, testosterone is required for virilization, normal sexual function, and both stimulation and maintenance of bone and muscle mass. Epidemiological studies have shown a progressive decline in testosterone levels with ageing in men. The clinical significance of this decline is still unclear, and there is controversy...

To understand the sex reversal characteristics in the longtooth grouper (Epinephelus bruneus), this study examined the sex reversal and artificial masculinization of wild caught E. bruneus reared in indoor rearing tank after a 17α-methyltestosterone injection. To domesticate a broodstock, 64 wild caught E. bruneus, between 47.0 to 110.0 cm in total length and from 1.5 to 21.4 kg in body weight,...

Gene expression differences between the sexes account for the majority of sexually dimorphic phenotypes, and the study of sex-biased gene expression is important for understanding the genetic basis of complex sexual dimorphisms. However, it has been difficult to test the nature of this relationship due to the fact that sexual dimorphism has traditionally been conceptualized as a dichotomy betwe...

Pregnant rats were injected with 4 mg of testosterone propionate (TP) from days 15 to 22 of pregnancy or a single dose of 4 mg TP on day 17 or 21 of pregnancy. Female offspring treated with TP or the vehicle prenatally were sacrificed at 90 days of age. The volume of the cluster of intensely stained neurons in the medial preoptic area, the "sexually dimorphic nucleus of the preoptic area" (SDN-...