The Effects of Chronic Feed Restriction on KNDy Neurons in the Ovine Hypothalamus

Andrew Seman* , Stan Hileman , Ph.D., Max Giesgraber , Casey Nestor
School of Medicine, West Virginia University, Morgantown, WV 26508

Presentation Category: Health Sciences (Poster presentation)

Student’s Major: Biomedical Engineering

Undernutrition has a negative impact on reproduction in several species. The neural mechanisms whereby food restriction suppresses fertility are not completely known. Neurons located in the arcuate nucleus of the hypothalamus that coexpress kisspeptin, neurokinin B (NKB), and dynorphin (i.e. KNDy neurons), are critical for the secretion of gonadotrophin releasing hormone (GnRH), a decapeptide that directly controls reproduction. Kisspeptin and NKB stimulate GnRH release, thus this study will test the hypothesis that reductions in GnRH secretion that occur in response to chronic feed restriction will be associated with decreased expression of kisspeptin and NKB. Female lambs of about 6 months of age were assigned to either normal feed intake (n=8) of fed to lose 15%-20% of their body weight over 9 weeks (n=9) Animals were bled every two weeks to measure luteinizing hormone (LH) secretion as a peripheral surrogate of hypothalamic GnRH release. Hypothalami were then collected and are being assessed for kisspeptin and NKB cell numbers within the arcuate nucleus via immunocytochemistry. We predict to find reduced numbers of kisspeptin and NKB immunopositive neurons. These results would further support the idea that undernutrition inhibits reproduction through a reduction in stimulation of GnRH release by KNDy neurons. Metabolic changes have been documented to have a significant impact on the reproductive process. Results from this study will provide novel information on the neural pathways linking metabolism and reproduction.

Funding: USDA

Program/mechanism supporting research/creative efforts: WVU's Research Apprenticeship Program (RAP) & accompanying HONR 297-level course