Effect of lactose feeding on cell renewal , disaccharidase activity and calcium - binding protein content in the intestinal mucosa of rats

binding protein,(CaBP) content and the empty liveweight calcium content. These measurements were carried out on rats eating a semi-synthetic diet since weaning containing 30 p. 100 lactose. In controls, carbohydrates were supplied in the form of starch and a vitamin D supplement was given. Administration of lactose caused cecum hyperplasia in ten 4-month old animals. The morphology, cell renewal rate and disaccharidase content ’of the small intestine were unmodified as compared to control values. CaBP content, measured in control animals 2, 3, 4, and 5 months old, decreased with age in the duodenum. CaBP disappeared from the jejunum and ileum at 3 months of age. When a diet containing lactose and vitamin D was given, CaBP content decreased at all levels and disappeared from the duodenum when the rats were 5 months old. As compared to the pair-fed controls, calcium content of the whole aimal, deprived of vitamin D and given calcium, was the same in ten 4-month old rats and higher in seven 12-month old subjects. The administration of lactose caused no changes in the small intestine which could explain the increased absorption and retention of calcium. The decrease in CaBP content indicated that lactose increases absorption by a mechanism which is not related to active vitaminodependent transfer.