Meeting Abstract
Endocrinologists have traditionally focused on circulating hormone levels. In the case of steroid hormones, circulating steroids can be locally metabolized within the brain to either more active or less active signalling molecules. Furthermore, the brain can synthesize steroids (“neurosteroids”), such as testosterone and estradiol, de novo from cholesterol or from inactive prohormones in the blood. For such reasons, steroid levels in the brain can be far higher than steroid levels in the blood. Recent data suggest that social interactions rapidly modulate neurosteroid synthesis in songbirds and other species. In addition, steroids have rapid effects on social behavior in songbirds and other species. Taken together, the data suggest that locally-synthesized steroids are more likely to act via non-genomic mechanisms than systemic steroids in the circulation.
