Peripheral but not central leptin treatment increases numbers of circulating NK cells, granulocytes and specific monocyte subpopulations in non-endotoxaemic lean and obese LEW-rats

Abstract

Leptin, a hormone mainly generated by adipocytes, acts centrally in the hypothalamus to regulate body weight and energy expenditure. However, there is strong evidence that leptin is also involved in cell-mediated immunity and cytokine crosstalk. In the present study the effects of diet-induced obesity and central and peripheral leptin treatment on leukocyte subsets and cytokine production was investigated. Leptin was injected either intravenously (i.v.) or intracerebroventricularly (i.c.v.) in male endotoxaemic or vehicle-treated healthy LEW-rats. Numbers of blood leukocyte subsets were analysed by FACS and cytokines (TNF-α and IL-6) by ELISA. Results showed that peripheral rather than centr..