Finding the sweet spot

Mouse models of streptozotocin (STZ)–induced diabetes are highly sensitive, and researchers must fine tune experimental conditions carefully before using these mice in preclinical studies. Blood glucose levels of diabetic mice tend to fluctuate unpredictably, making it difficult for researchers to evaluate the effects of various insulin treatments. Dekel et al. examined several factors that might influence blood glucose stability in male mice with STZ-induced diabetes. Potential factors included STZ dose, initial mouse weight, fasting regimen and light:dark cycle. The authors make several suggestions for maintaining stable blood glucose levels in mice injected with STZ. See page 55

No cause for alarm

Credit: Sven Klaschik

To comply with national fire safety guidelines, facility managers must install fire alarms in appropriate locations and maintain and test the alarms regularly. Exposure to such alarms might cause stress to research animals, which may influence experimental results. Godfrey and Silverman exposed mice to the strobe light component of a standard fire alarm and evaluated mouse fecal corticosterone excretion, which is known to be an index of stress. Mice were exposed to the flashing light for 5 min during either the dark or the light period of the light:dark cycle. The authors collected mouse feces every 6 h for 24 h before and after exposing mice to the stimulus and examined patterns of fecal corticosterone excretion over time. See page 61