Effects of metformin on female egg-laying and post-reproductive survival.

<p>(<b>A</b>) Egg-laying profiles of wild-type females treated with 0 mM, 5 mM, 10 mM, 25 mM, 50 mM and 100 mM metformin. Eggs were counted from 10 vials per treatment (10 females per vial) over a 24 hour period after 7, 14 and 21 days of metformin treatment. Data are shown as means ±SEM. * denotes statistically significant difference (<i>P</i><0.05). No significant differences were observed in egg-laying between females on 0 mM, 5 mM and 10 mM metformin at any time point. After 7 days of treatment, females on 25 mM and 50 mM metformin laid significantly more eggs than untreated controls. After 14 days of treatment, females on 50 mM laid significantly fewer eggs than untreated controls. Females on 100 mM metformin laid significantly fewer eggs than untreated controls at all time points. (<b>B</b>) Survival curves for post-reproductive wild-type females maintained on food containing no metformin or final concentrations 25 mM and 50 mM metformin. Flies (n = 250 for each concentration) were switched onto food containing metformin at 39 days of age (red arrow). Females maintained on 25 mM or 50 mM showed reduced survival compared to flies maintained in the absence of metformin (<i>P</i><0.001 by the Log-rank test).