Insulin stimulates lactate production in subcutaneous, omental and preperitoneal adipocytes : induction of insulin resistance by leptin / by Marilyn J. Kehoskie.
| Author/creator | Kehoskie, Marilyn J. author. |
| Other author | Sinha, Madhur K., degree supervisor. |
| Other author | East Carolina University. Department of Biology. |
| Format | Theses and dissertations |
| Production | 2000. |
| Description | vi, 46 leaves : illustrations ; 28 cm |
| Supplemental Content | Access via ScholarShip |
| Subjects |
| Summary | We have developed a physiologically more relevant bioassay for insulin action on subcutaneous, omental and preperitoneal human adipocytes. In the first series of experiments, basal and insulin (0.01,0.1, 1, 10 and 100 nM) stimulated lactate production in subcutaneous, omental, and preperitoneal was determined in the absence and presence of 100 nM leptin. Insulin stimulated lactate production in a dose dependent manner in 3 fat depots. Insulin response was highest in omental (p<0.05) compared to subcutaneous and preperitoneal, although insulin sensitivity was similar in all 3 tissues. 4hr leptin (100 nM) treatment resulted in decreased insulin response to lactate without altering insulin sensitivity. In a larger series of experiments (n=23) we compared basal and maximally insulin stimulated lactate production in 3 fat compartments (n=23). There was a positive correlation between cell size and BMI in subcutaneous (p<0.05) and BMI and maximal lactate production in subcutaneous adipocytes (p<0.05). When the data was analyzed by ethnic populations, in Caucasians, a positive correlation existed between BMI and maximal lactate production in subcutaneous adipocytes (p<0.05). In African-Americans there was an opposite effect. Similar observations were made with cell size and basal and maximally stimulated lactate production. In summary: 1) A physiologically more relevant bioassay for insulin action in human adipocytes, i.e. increased lactate response to insulin in a dose dependent manner at normal glucose levels is described. 2) Insulin induced glucose utilization (% control), is higher in omental than in subcutaneous and preperitoneal adipocytes. 3) Leptin appears to induce insulin resistance with regard to lactate production in subcutaneous and omental tissues. 4) A positive correlation is observed between BMI and maximal lactate production in subcutaneous adipocytes. Opposite effects are observed between subcutaneous and preperitoneal tissues among the same ethnic group. However, differences between subcutaneous and preperitoneal tissue were opposite in Caucasians and African-Americans. |
| General note | Submitted to the faculty of the Department of Biology. |
| General note | Advisor: Madhur K. Sinha |
| Dissertation note | M.S. East Carolina University 2000 |
| Bibliography note | Includes bibliographical references (leaves 39-46). |
| Genre/form | Academic theses. |
| Genre/form | Academic theses. |
| Genre/form | Thèses et écrits académiques. |