Weight gain and body composition in lithium treated rats

Long-term lithium treated growing animals given 0.8-2.0 mmol/kg/day had a slightly but significantly faster weight gain than control animals. Greater doses did not give rise to significantly increased weight gain. Body composition, i.e., the percentage of water, fat, ash and "protein" was not affected in the faster growing lithium treated animals. The wet weight and the weight after drying of the stomach (with content) was increased shortly (hours) after the acute administration of lithium. The duration of the effect depended on the dose given. The weight of the large intestine was also increased after a dose of lithium, but only after some days of lithium pretreatment and mainly the wet weight. The effect was small but similar on the small intestine. In long-term lithium treated rats did the faecal weight and volume increase mainly due to increased water content, but only after some days of lithium treatment.