ALTERATION OF THE BED NUCLEUS OF THE STRIA TERMINALIS (BNST) IN YOUNG FEMALE DJUNGARIAN HAMSTERS (PHODOPUS-CAMPBELLI) EXPOSED TO ADULT MALES

Central components of the vomeronasal system appear to mediate extrahypothalamic control of gonadotropin release during male-induced acceleration of puberty onset in female rodents. In order to describe the bed nucleus of the stria terminalis (BNST) and to determine whether this component of the vomeronasal system is altered following early puberty onset, the anterior BNST of female Djungarian hamsters (Phodopus campbelli) was subdivided into three regions: medial, lateral, and ventral. The cross-sectional area, soma size, and neuronal density of each subdivision was compared among female hamsters in three groups: (1) young females showing accelerated reproductive development following a period of housing with an adult male, (2) young females matched by age with the accelerated females but housed alone during the same period, and (3) older females at the age of spontaneous puberty. Females housed with an adult male and undergoing accelerated puberty onset had significantly smaller lateral anterior BNST subdivisions than females housed alone for the same period (10 days following weaning) or housed alone until the age of spontaneous puberty onset (25 days following weaning). The size of the ventral and medial subdivisions was not different in the three groups. Furthermore, although soma size and neuronal density differed markedly among the anterior BNST subdivisions, these subdivision characteristics were similar in the accelerated, prepubertal, and older pubertal females. Our finding demonstrates that a central component of the vomeronasal system undergoes neuroanatomical alteration in response to environmental stimuli and recommends further examination of the BNST during this dynamic ontogenetic period. © 1993 Academic Press, Inc.