Fig. 6.

Endothelium-dependent relaxation response to acetylcholine (ACh). Aortic rings were subjected to increasing doses of ACh for determination of endothelium-dependent relaxation function. Values are means ± SE, n = 10–20/group. Sigmoidal dose-response curves were fitted for C57BL6/J WT mice (A) and ob/ob leptin-deficient mice (B) exposed to RA (□, solid line), RA + leptin (■, dotted line), IH (▵, dashed line), and IH + leptin (▴, dot-dash line) with the bottom values constrained to 0. The maximum relaxation responses determined from the fitted curve were compared for WT (C) and ob/ob animals (D). Half-maximal effective concentrations of ACh were also compared for WT (E) and ob/ob animals (F). *P < 0.05 vs. RA, †P < 0.05 vs. no leptin, ‡significant interaction between IH and leptin; §P < 0.05 ob/ob vs. WT.