But little is known about the kinds of changes estrogen triggers. Although Arbogast's team is in the beginning stage of this project, they've already found evidence that when brainstem cell cultures from normal rats are exposed to estrogen, TH activity goes up. Once they've confirmed how the estrogen is acting, the team will investigate whether it has a different effect on the same cells in a strain of rats that, like some people, are genetically inclined to high blood pressure. T easing out the cellular mechanisms by which reproductive hormones do their thing is Arbogast's forte. Like the brainstem, the hypothalamus helps control many basic processes, from temperature to reproduction.
Dopamine is produced elsewhere in the brain too, and plays many roles in the body.
Prolactin affects reproductive behavior, and it's essential to milk production in the nursing mother. Most of the time, prolactin levels in both females and males need to walk a fine line. Too little or too much, and the result can be infertility. Normally, an excess of prolactin circulating in the body cues the dopamine-producing neurons to swing into high gear. The extra dopamine they make, in return, cues the pituitary gland to make less prolactin.