Fig. 5.
Prolonged treatment with a low dose of clenbuterol does not increase insulin levels (OGTT) but improves insulin sensitivity. The data are from the same experiment as in Fig. 4 and ESM Fig. 2. Mice were fasted for 5 h. Plasma insulin was measured before and 15 min after glucose gavage in mice pre-treated with clenbuterol for 4 (a) and 18 (b) days; n = 6–7. The data were analysed with unpaired two-tailed Student’s t test separately for fasting and glucose stimulated conditions. (c) ITT performed on 25th day of treatment with clenbuterol. After 5 h of fasting, insulin (1 U/kg body weight) was injected i.p. and blood glucose was measured after 15, 30, 60, 90 and 120 min; n = 6–7. Insulin response from (c) is presented as change of blood glucose (15 min minus 0 min) and (30 min minus 0 min, p = 0.056) (d), and rate of blood glucose disposal (KITT) (e). The data in (c, d) were analysed by two-way ANOVA with Sidak’s multiple comparison test, and in (e) with unpaired two-tailed Student’s t test. In all graphs: *p < 0.05, **p < 0.01 vs vehicle