Metabolic and Endocrine Control of Behavior

Lehigh University, Bethlehem PA

Investigators

Abstract

Energy availability is an environmental factor that plays a role in regulating reproduction in animals, both wild and domestic, but we know very little about the mechanisms that link energy availability to fertility and reproductive behavior. When food is scarce, reproductive functions such as seasonal breeding, puberty, and lactation in mammals may be strongly reduced. Not long ago the molecule leptin, naturally made and secreted by fat body cells, was discovered to act as a hormone affecting metabolism. It now appears that leptin may signal the brain about how much metabolic fuel is available for an animal, and it may also act as a modulator of reproductive readiness. This project addresses those hypotheses using pharmacology, molecular biology and behavioral approaches on a rodent species chosen for its comparatively short and very regular periodic ovulatory (estrous) cycle. The project determines the critical events involving leptin's association with the phenomenon of anestrous (the disappearance of the usual estrous) when oxidizable metabolic fuel is low, even when body fat levels may be high. The project will also localize where in the brain the leptin acts to influence estrous cyclicity. Results will give a novel perspective for understanding the relationship between energy levels and reproductive functions, and how organisms adapt their reproductive strategies to environmental perturbations, so the impact will extend beyond neuroendocrinology. In addition, the project will foster considerable integration of education with research, and of fostering careers of women in biology, because of the location at a largely undergraduate school and because of the strong involvement of the principal investigator with teaching and mentoring students.