Obesity is a serious concern in human health in the United States. Since excessive adipose tissue development is the visible symptom, it is worthwhile to study the mechanisms of adipose development. Mature adipocytes which have reached a maximum size may be critical in initiating hyperplasia. Removing mature adipocytes will enable the studying of adipocyte hyperplasia in their absence. Due to technical limitations, the origin of the newly synthesized adipocytes is still unknown. Monoclonal antibody against rat adipocyte plasma membranes can identify a small number of stromal-vascular cells isolated from adipose tissue. These cells may be termed preadipocytes. In order to elucidate the role of these antibody-positive cells on adipose accretion, I will determine the effect of dietary manipulation on the antibody positive cell pool size and examine adipocyte development in the absence of these antibody positive cells. Specifically, 1) monoclonal antibodies specific to epididymal adipocytes will be produced. Adipocyte plasma membranes will be isolated and used for hybridoma production. Adipocyte specific clones will be identified. 2) Effect of dietary treatment on the antibody-positive cell pool will be determined. Adipose stromal-vascular cells and mature adipocytes will be isolated from rats raised on different dietary treatments. Number and size of mature adipocytes will be measured using Coulter Counter, and antibody-positive cells will be quantified using fluorescent activated cell sorter (FACS). 3) The effect of adipocyte-specific immunoconjugate on adipocyte development in vitro and in vivo will be determined. Conjugate will be prepared using adipocytespecific antibodies and ricin A chain. Primary culture of adipose stromal-vascular cells will be used to assess the effect of immunoconjugate on the development of adipocytes in vitro. Development of adipocytes in vivo will be assessed in rats treated with immunoconjugate, and subsequent re-establishment of the adipocytes using Coulter Counter and immunofluorescence staining will be determined. Results from these experiments will increase our understanding of the mechanisms involved in adipocyte development.
