This binding plays an important role in regulating the transport, tissue delivery, bioactivity, and metabolism of testosterone. Fairer offers from test subjects with higher testosterone in the original study increase the likeliness of the offer being accepted by the negotiating partner, therefore decreasing the probability of both participants leaving without any money. This could explain why some studies find a link between testosterone and pro-social behaviour, if pro-social behaviour is rewarded with social status. Rats who were given anabolic steroids that increase testosterone were also more physically aggressive to provocation as a result of "threat sensitivity". Moreover, the conversion of testosterone to estradiol regulates male aggression in sparrows during breeding season. In one experiment, subjects who interacted with handguns showed higher testosterone levels and aggression than those who interacted with toys. The rise in testosterone during competition predicted aggression in males, but not in females.
With the loss of the placenta, estrogen levels decrease 100–1000-fold during a period of a few days (Nott et al., 1976; O'Hara and Swain, 1996; O'Hara et al., 2000). These findings add to previous studies suggesting that menopausal women gain less benefit from antidepressant treatments compared to women during their reproductive years (Pinto-Meza et al., 2006; Pae et al., 2009). Both, estrogen and progesterone have been demonstrated to modify the serotonergic responsivity to selective serotonin reuptake inhibitors (SSRI)-administration (Benmansour et al., 2012). Thus, assigning the effects of estrogen on serotonin to a homogenous functional class of stimulation or inhibition seems not to be feasible.
Higher testosterone levels in men reduce the risk of becoming or staying unemployed. Testosterone levels play a major role in risk-taking during financial decisions. If a father's testosterone levels decrease in response to hearing their baby cry, it is an indication of empathizing with the baby. While the extent of paternal care varies between cultures, higher investment in direct child care has been seen to be correlated with lower average testosterone levels as well as temporary fluctuations.
Testosterone’s action is mediated through androgen receptors (AR) and estrogen receptors (ER), indicating a complex interplay between sex hormones and dopamine signaling in the brain. Furthermore, the opposing effects of testosterone and estrogen on HPA axis activity suggest that sex hormones may differentially modulate stress sensitivity in males and females, which could contribute to gender differences in the incidence and symptomatology of stress-related psychiatric illnesses such as depression and schizophrenia. These gender differences appear attributable to sex hormones, since gonadectomy decreases stress-induced glucocorticoid secretion in adult female rats (PND120) (Burgess and Handa 1992) and increases glucocorticoid secretion in adult males (Handa et al. 1994). Female rats display increased basal levels of corticosterone relative to males during adolescence (PND33–48) (Martinez-Mota et al. 2011; McCormick et al. 2005) and in adulthood (PND150) (Weinstock et al. 1998), while male rats display lower stress-induced hormone secretion after puberty than before (Foilb et al. 2011; Romeo and McEwen 2006).
This stress-induced dopamine increase is positively correlated with the magnitude of salivary cortisol response (Pruessner et al. 2004). In humans (ages 18–30), dopamine release occurs in the PFC in response to psychological stress (Nagano-Saito et al. 2013), in parallel with decreased working memory-related and reward-related PFC activation (Ossewaarde et al. 2011; Qin et al. 2009) and impaired working memory performance in males (Schoofs et al. 2013). At a molecular level, testosterone-induced increases in these dopamine parameters may be largely mediated via AR, rather than ER, since they are mainly mimicked by DHT (Purves-Tyson et al. 2012). This may be particularly pertinent in schizophrenia, as males are more severely impacted (McGrath et al. 2004), and cognitive functions including working memory, processing speed, and verbal memory may be related to testosterone levels in men with schizophrenia (Moore et al. 2013). The relatively few studies in clearly defined ages within the adolescent period in rodents indicate that testosterone can regulate dopamine neurotransmission.
More work needs to be done to determine whether the effects testosterone on cell proliferation in the SVZ lead to changes in neurogenesis within the olfactory bulbs. For both female rats and mice, prolonged exposure (14–21 days) to estradiol caused a decrease in neurogenesis within portions of the olfactory bulbs 80,81, although the relative effects on the accessory and main olfactory bulbs differed between the two species. Studies with mice and rats have shown that females have higher levels of cell proliferation within the SVZ than do males 76,77,78,79. They also found that testosterone levels were lower in both males and female cowbirds outside the breeding season, suggesting that testosterone might suppress hippocampal neurogenesis in cowbirds, but this idea has not been tested experimentally. Similarly, male starlings (Sturnus vulgaris) given testosterone implants showed an increase in HVC volume and an increase in the number of actively proliferating cells along the ventricular zone . However, a subsequent study demonstrated that testosterone implants given to both female and male canaries caused an increase in cell proliferation specifically along the ventral portion of the ventricular zone . Testosterone implants given to female canaries caused an increase in neurogenesis within the HVC via enhanced cell survival but not cell proliferation .
In addition to these cellular effects, recent studies report that the interaction between estrogen and glutamate can affect cognitive domains such as working memory and executive function under harmful conditions. The latter might point toward the well-established neuroprotective effects (Mattson et al., 1997; Wang et al., 2001) of ovarian hormones from insults such as oxidative stress and glutamate excitotoxicity. The blockade of NMDA receptors with antagonists attenuates the effects of estrogen on neuronal correlates of memory, such as long-term potentiation (LTP) (Brinton et al., 1997; Foy et al., 1999).

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