We study the cellular processes by which steroid hormones act in neurons, particularly with respect to their involvement in reproductive behavior. During the estrous cycle of female rats and other rodent species, the ovarian hormones, estradiol and progesterone, regulate the expression of reproductive behaviors. The sensitivity of specific neurons to each of the hormones is determined in part by the concentrations of hormone-specific intracellular receptors. Intracellular steroid hormone receptors are essential in mediating the effects of steroid hormones on some behaviors, possibly by modulating gene transcription and synthesis of specific proteins.
A new interest of our group is the study of the long-term effects of exposure to particular stressors around the time of puberty. We have recently discovered that exposure to particular stressors (shipping; a bacterial endotoxin), but not others, only in the peripubertal period causes enduring changes in response to ovarian steroid hormones (i.e., defeminization of response to estradiol and progesterone) in adulthood months later. We have seen dramatic change in response to estradiol and progesteorne on reproductive behavior, cognitive function, depression-like and anxiety-like behaviors. In studies of cellular mechansims underlying this altered response, we have observed changes in levels of steroid hormone receptors in particular neuroanatomical areas in adulthood in response to these peripubertal treatments. Our current work focuses on the mechanisms by which these particular stressors cause enduring changes in an animal's response to sex steroid hormones.