|Dyer, C J - UNIVERSITY OF MISSOURI|
|Simmons, J M - UNIVERSITY OF MISSOURI|
|Keisler, D H - UNIVERSITY OF MISSOURI|
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: October 22, 1996
Publication Date: N/A
Technical Abstract: Neuropeptide Y, a protein highly expressed in the central nervous tissues of undernourished animals, is a potent regulator of food intake and reproduction. Leptin, a protein expressed by adipose cells, has been reported to reduce hypothalamic NPY expression. We have detected expression of the NPY receptor subtype Y1 (but not Y2) mRNA in adipose tissue collected from sheep using ribonuclease protection assays (RPA). Based on this finding we hypothesized that NPY-Y1 receptors in adipose may permit NPY to regulate leptin expression in a direct and rapid manner. To test this hypothesis, contralateral tailhead adipose samples were biopsied from wether lambs before and 30 minutes after a single i.v. injection of 0 or 50 ug porcine NPY in saline. Total cellular RNA was isolated and leptin mRNA expression quantified by utilizing an RPA and specific radiolabelled cRNA probes for ovine leptin and B-actin. The difference between pre- and post-injection levels of leptin mRNA was compared within animals across treatments. The change (increase) in leptin expression was greater in wethers injected with 50 ug NPY (p<.05) than in wethers injected with saline alone. These data provide evidence for the existence of a mechanism (sic NPY-Y1 receptor) by which NPY may regulate leptin mRNA expression in sheep, providing a means by which homeostasis is maintained in the normal animal.