Serum leptin concentrations after surgery in young rats

OBJECTIVES: We describe changes in serum leptin concentrations after surgery (laparotomy, partial hepatectomy, splenectomy, and unilateral nephrectomy) in young male rats. Because we presumed that pain and inflammation would influence food intake and subsequent leptin release, laparotomized and partially hepatectomized rats were treated with ibuprofen. METHODS: Preoperative blood samples were taken from the retroorbital sinuses, and postoperative blood samples were taken from the aorta, vena portae, and vena cava 18 h after surgery. Serum leptin concentrations were estimated by radioimmunoassay. RESULTS: Pre- and postoperative serum leptin concentrations did not differ significantly in rats with partial hepatectomy (5.1 ± 0.4 versus 4.2 ± 1.1 μg/L), splenectomy (6.1 ± 0.4 versus 5.0 ± 0.6 μg/L), or unilateral nephrectomy (4.1 ± 0.7 versus 5.0 ± 1.3 μg/L). Significant decreases in serum leptin were observed after laparotomy (8.1 ± 0.9 versus 3.7 ± 0.5 μg/L), laparotomy plus ibuprofen treatment (8.9 ± 1.6 versus 3.1 ± 0.4 μg/L), and partial hepatectomy plus ibuprofen treatment (5.4 ± 0.6 versus 3.2 ± 0.3 μg/L). We observed no significant differences in serum leptin concentrations measured in different regions of the body. CONCLUSIONS: Surgical interventions in young rats are accompanied by decreases in serum leptin. The liver, spleen, and kidney may participate in leptin clearance. Ibuprofen treatment leads to additional decreases in serum leptin concentrations.