Androgen and Estrogen Receptors Coexist within Individual Neurons in the Brain of the Syrian Hamster

Abstract

Many aspects of reproductive neuroendocrine function and sexual behavior are responsive to both androgens and estrogens, suggesting that receptors for these steroid hormones may reside within single cells in brain regions that control reproductive function. We determined the distribution of estrogen receptor-containing neurons in 40-µm coronal brain sections in gonadectomized, DHT-treated male Syrian hamsters using immunocytochemistry with the H222 antibody (10 µg/ml; Abbott Laboratories). Subsequently, we colocalized estrogen receptors with androgen receptors using the PG-21 antibody (0.5 µg/ml; G.S. Prins). In males, the distribution of estrogen receptor-containing neurons was similar to that reported previously for the female hamster. Colocalization of androgen and estrogen receptor immunoreactivity was observed in brain regions that contain numerous androgen and estrogen receptor-positive neurons, including subdivisions of the medial preoptic area, bed nucleus of the stria terminalis, ventromedial nucleus of the hypothalamus, and the amygdalohippocampal area. Single-labelled estrogen receptor-containing neurons were most numerous in the amygdalohippocampal area and the rostral medial preoptic nucleus; androgen receptor-immunoreactive cells were most abundant in the ventral premammillary nucleus and the lateral septum. These data suggest the potential of androgens and estrogens to influence neuronal function within individual steroid receptor-containing neurons of the hamster limbic system.

The vertebrate social behavior network: Evolutionary themes and variations

“…However, sex steroid receptors are most dense in hypothalamic areas that are caudolaterally adjacent to the anterior tuberal nucleus (Fine et al, 1990(Fine et al, , 1996Forlano et al, 2005). This topography is similar to that observed in tetrapods for the VMH core and shell (or medial and lateral VMH, respectively), with most sex steroid receptors being found in the shell (e.g., Wood and Newman, 1995); thus much of the anterior tuberal nucleus may be comparable to the VMH core. 7 The midbrain also includes a variety of tegmental sites that are important for social behavior.…”

“…These include aggression, appetitive and consummatory sexual behavior, various forms of communication, social recognition, affiliation, bonding, parental behavior and responses to social stressors (Kirkpatrick et al, 1994;Kollack-Walker and Newman, 1995;Bamshad and Albers, 1996;Coolen et al, 1997;Kollack-Walker et al, 1997;Wang et al, 1997;Lonstein et al, 1998;Morgan et al, 1999;Delville et al, 2000;Kalinichev et al, 2000;Gammie and Nelson, 2001;Heeb and Yahr, 2001;Sheehan et al, 2001;Ferguson et al, 2002;Cushing et al, 2003;Lim and Young, 2004). The nodes are also bidirectionally connected (Risold and Swanson, 1997b;Coolen and Wood, 1998;Dong and Swanson, 2004), and each area contains sex steroid receptors that are essential for the sexual differentiation and temporal coordination of social behavior (Morrell and Pfaff, 1978;Commins and Yahr, 1985;Simerly et al, 1990;Wood and Newman, 1995). The mammalian brain obviously contains a large number of other areas that are relevant for social behavior (e.g., other basal forebrain areas that regulate stress and reward processes, and cortical areas that serve executive functions); thus Newman's network should be regarded as the "core" of the social brain, not the social brain in toto.…”

Social status and sex independently influence androgen receptor expression in the eusocial naked mole-rat brain

“…As a rule, AR is found throughout the hypothalamus and preoptic area as well as in telencephalic structures that project to these regions. Indeed, AR is found in the same structures investigated here (BST, PVN, VMH, MeA, and PMv) in diverse mammalian species including (but not limited to) rats, mice, hamsters, ferrets, opossums, sheep, and humans (e.g., Clancy et al, 1994;Fernández-Guasti et al, 2000;Herbison et al, 1996;Iqbal et al, 1995;Kashon et al, 1996;Lu et al, 1998;Simerly et al, 1990;Wood and Newman, 1995). The BST, PVN, MeA, VMH, and PMv comprise key nodes of an interconnected neural circuit that regulates neuroendocrine function and couples the expression of reproductive behaviors with appropriate environmental stimuli.…”

“…Androgens act via androgen receptors (AR), which are ligand-dependent transcription factors belonging to the superfamily of intracellular nuclear receptors (Prins, 2000). In other species, the AR is expressed in many of the brain regions involved in the control of sex-typical reproductive behaviors (e.g., Choate and Resko, 1992;Commins and Yahr, 1985;Kashon et al, 1996;Lu et al, 1998;Simerly et al, 1990;Wood and Newman, 1995). In addition, sex differences in the brain are organized and/or activated in adulthood by circulating testosterone acting via AR, or after conversion to an estrogen and binding to an estrogen receptor (ER), and both AR and ER are expressed in neural regions that are sexually dimorphic (e.g., Commins and Yahr, 1985;Simerly et al, 1990;Wood and Newman, 1995).…”

Testosterone and nucleus accumbens dopamine in the male Syrian hamster

“…In light of the results of these data, we suspect that the relationship between the mesolimbic DA system and AAS abuse may be indirect. In fact, the relative paucity of nuclear androgen receptors in Acb or the VTA is well-documented (Kritzer, 1997;Simerly et al, 1990;Wood and Newman, 1995). Therefore, the influence of AAS on the mesolimbic DA system is likely to be mediated by androgen-sensitive afferents and/or non-classical androgen receptors (Simoncini and Genazzani, 2003).…”