Abstract: The present invention relates to a variant form of the receptor for the obese gene product. In particular, the invention relates to methods of detecting this receptor variant in cells and tissues of obese individuals. In addition, it relates to methods of inhibiting or down-regulating expression of this variant in cells to augment their responsiveness to weight regulation by leptin as well as methods of using compounds to directly activate signal transduction pathways associated with this ligand-receptor system.

Abstract: The present invention relates to methods for using various forms of a novel receptor expressed by hematopoietic and endothelial cells. An additional variant form of this receptor has been detected in brain cells and shown to bind to the obese gene product, leptin. Therefore, leptin may be used to stimulate the growth and development of receptor-positive hematopoietic and endothelial cells in vitro and in vivo. In addition, this receptor is selectively expressed in hematopoietic progenitor cells with long-term repopulating potential. Thus, agents that specifically bind to this receptor may be used to identify and isolate progenitor cells for a variety of clinical applications.