This schematic shows how estrogens and androgens regulate the mesolimbic DA system at the VTA-NAc synapse. Estrogens enhance DA activity by increasing the number of VTA DA neurons (blue), increasing DA release, decreasing the rate of DA reuptake, and increasing D1 and D2 receptor density at the postsynaptic neuron (green). Androgens can also enhance DA activity by increasing TH expression, increasing DA release and decreasing the expression of DAT, however, some of the effects of androgens may be mediated by aromatization to estrogens. Different forms of ELS can increase or decrease estrogen and androgen levels in males and females, altering gonadal hormone regulation of the mesolimbic DA system. DA, dopamine; TH, tyrosine hydroxylase; DOPA, L-dihydroxyphenylalanine; DAT, dopamine transporter; VTA, ventral tegmental area.