Androgen and estrogen concentrating neurons in chemosensory pathways of the male Syrian hamster brain

Abstract

The medial preoptic area (MPOA), bed nucleus of the stria terminalis (BNST), and medial amygdaloid nucleus (Me) are essential for male sexual behavior in the Syrian hamster. These nuclei received chemosensory stimuli and gonadal steroid signals, both of which are required for mating behavior. The objective of this study was to compare the distribution of androgen- and estrogen-concentrating neurons in MPOA, BNST, and Me in the adult male hamster using steroid autoradiography for estradiol (E2), testosterone (T) and dihydrotestosterone (DHT). Adult males (n = 4 per group) received two i.p. injections of tritiated steroid 4-7 days after castration. Six-microns frozen sections through the brain were mounted onto emulsion-coated slides, and exposed for 11-16 months. In MPOA, BNST, and Me, neurons were more abundant and heavily labelled after [3H]E2 treatment than after either [3H]T or [3H]DHT. Tritiated estradiol- and DHT-labeled cells were found throughout the rostrocaudal extent of Me, with a high concentration in posterodorsal Me. Tritiated testosterone treatment labelled cells largely within posterodorsal Me. In MPOA, the majority of E2-, T-, and DHT-labelled neurons were in the medial preoptic nucleus (MPN) and the preoptic continuation of the posteromedial bed nucleus of the stria terminalis (BNSTpm). Few T-labelled cells were present outside these subdivisions. In the BNST, E2- and DHT-labelled neurons were present in all subdivisions, whereas T labelling was confined to the antero- and posteromedial subdivisions of BNST. These results suggest that the distribution of androgen- and estrogen receptor-containing neurons overlap considerably in nuclei which transmit chemosensory signals in the control of mating behavior.

Effects of Lesions of Nucleus taeniae on Appetitive and Consummatory Aspects of Male Sexual Behavior in Japanese Quail

“…Studies of AR, ER· and ERß in other avian species besides quail have found similar patterns of high expression for the mRNA and/or protein of these important components of steroid hormone action in Tn [Arnold et al, 1976;Balthazart et al, 1992;Gahr et al, 1993;Ball et al, 1999;Bernard et al, 1999]. The medial amygdala in rats exhibits a similar pattern of expression for both of these three types of sex steroid receptors [Wood et al, 1992;Wood and Newman, 1995a;Kuiper et al, 1998]. However, a critical examination of the connectivity of this nucleus does not necessarily support the proposition that Tn is homologous to the mammalian Me.…”

Effect of juvenile hormone on the central nervous processing of sex pheromone in an insect

“…In mammals, gonadal steroids have been shown to control the behavioral responses to pheromones by actions on the central nervous system (22). Several studies have localized receptors for gonadal steroids within neurons (23). It is suggested that steroids could influence the behavior by regulating the synaptic transmission between peripheral neurons and more central areas.…”

Gonadal Steroid Attenuation of Developing Hamster Facial Motoneuron Loss by Axotomy: Equal Efficacy of Testosterone, Dihydrotestosterone, and 17-β Estradiol

“…To determine when androgen receptors first appear in hamster FMNs, an AR immunocytochemistry time-course study using PG-21, an anti-AR antibody that has been well documented in the hamster (Wood et al, 1992;Wood and Newman, 1993Romeo et al, 2000), was performed on brainstem tissue sections from males and females ranging in age from P0 to P10. The AR is a steroid receptor that resides in the cytoplasm in an unliganded state and, after ligand binding, translocates to the nucleus (Kumar and Thompson, 1999;Aranda and Pascual, 2001).…”