These sex-specific differences suggest that E2 may lead to significant variations in physical and emotional responses between males and females. Nevertheless, all three receptors are present in the cardiovascular system, nervous system, and adipose tissues (Dahlman-Wright et al., 2006; Heldring et al., 2007; Prossnitz and Barton, 2011; Paterni et al., 2014). It is crucial to remember that intersex is a diverse spectrum, and the relationship between estrogen and individual presentations is highly nuanced. In rodents, adolescence can be considered to extend from the time just after weaning until after the completion of sexual maturity (Schneider 2008; 2013). Black arrows within shaded boxes indicate findings in adolescents, thick white arrows indicate findings made in young adults or adults that have yet to be demonstrated in adolescents, and thick purple arrows indicate findings in schizophrenia. Adolescent changes in dopamine signaling occur in the prefrontal cortex (PFC), which is responsible for working memory, and in subcortical regions, which are involved with probabilistic learning and reward (Morris et al. 2012; Weickert et al. 2009b). Additionally, teenage girls face a higher risk for depression than they did at a younger age and a greater risk for depression than their male counterparts (Hankin et al. 1998). You may not even need a supplement unless you are deficient in a particular hormone. And in some cases, supplements can cause unwanted and even serious side effects. Males display decreased apical dendritic length after stress, while females display increased apical dendritic length which can be ameliorated by ovariectomy and restored by ovariectomy combined with estrogen replacement (Garrett and Wellman 2009). The mechanisms underlying the effects of chronic stress on dopaminergic neurotransmission in adolescence have been illuminated by a small number of studies in adolescent animals, with additional clues provided by studies in adults. In adult (PND84) female rats, estrogen is protective against sensorimotor gating disruptions induced by DR1/DR2 agonist apomorphine, while testosterone treatment has no effect (Gogos et al. 2010; Gogos et al. 2012). In contrast, our group found that estrogen did not modify the expression of midbrain dopamine markers in male rats following adolescent gonadectomy (between PND45 and 60) (Purves-Tyson et al. 2012). Removal of circulating estrogen by ovariectomy of adult female rats (PND84) has been reported to reduce striatal DAT and increase DR2, and this can be reversed by estrogen replacement (Chavez et al. 2010). Interestingly, TH immunoreactive fiber densities and extracellular dopamine levels in the PFC increase after gonadectomy to higher levels than before surgery, but this is also prevented by testosterone replacement (Aubele and Kritzer 2011; Kritzer et al. 1999). Furthermore, perimenopausal estrogen depletion and greater activity of MAO-A are risk factors for Alzheimer's disease (Burke et al., 2004). Women receiving HRT earlier seem to improve their cognitive performance compared to either older HRT-treated women or untreated women (MacLennan et al., 2006). Several reviews and meta-analysis suggest small positive effects of HRT on verbal memory, attention, and reasoning (Hogervorst et al., 2000; LeBlanc et al., 2001; Rice and Morse, 2003; Weber et al., 2014). Until today, it has been an area of much debate whether women with depressive symptoms should be treated with HRT, antidepressants or both. They did, however, find a significant correlation between MAO-A binding and the tendency to cry (Rekkas et al., 2014), a psychological symptom that has been found as a subclinical phenomenon to occur during major shifts of sex hormonal environment (Sacher et al., 2010; Dowlati et al., 2014). Rekkas et al. have recently shown greater MAO-A binding in the prefrontal cortex during the perimenopausal transition phase compared with age-matched women during their reproductive years and during menopause (Rekkas et al., 2014). Strikingly, women with a previous history of depression, who also reported the use of antidepressants, had nearly 3 times higher risk of an earlier perimenopausal transition compared to non-depressed women (Harlow et al., 2003). Additionally, it has been shown to increase neurogenic output of excitatory progenitors in human brain organoids 10–12. Research has indicated individuals with autism spectrum disorder (ASD) have elevated androgen levels when compared to their peers. The influence of androgens on brain development may begin during fetal development. Thus, it is hypothesized that alterations of ARs or androgen interactions with ARs located in the CNS may play a role in various neurological diseases and serve as a target for disease management. Although the exact location and function of ARs in the adult brain remain under investigation, animal models have demonstrated the presence of ARs at multiple CNS locations. Androgens bind to these receptors and operate via genomic (DNA binding) or nongenomic pathways (non-DNA binding) that influence multiple signaling cascades essential for CNS function and neuroprotection. Following androgen binding, they convert to a nuclear receptor which influences gene expression through binding at specific DNA sequences.
