EVALUATION DE QUELQUES ELEMENTSCONSTITUTIFS DES CELLULES EPITHELIALESINTESTINALES CHEZ LE RAT PARMICROANALYSE DE RAYONS X AU COURSDE LA GESTATION, DE LA LACTATION ETDU DEVELOPPEMENT

The distribution and density of P and Ca were studied in the intestinal epithelium of rat foetuses and new-borns as well as pregnant and lactating females by of X-ray microanalysis. Pregnancy do not affect nor density neither distribution of P and Ca. On the contrary, the X-images realized on epithelium from a 14 day lactating rat showed aggregates of phosphorus and calcium in the same areas. In the 18 days old foetus, the distribution of the two elements is uniform. Their concentrations are great. The P concentration decreased on postnatal day 7, th;n increased on day 15. Its distribution remained unchanged. At same days, X-images of Ca showed that the concentration of this element is rather constant, whereas its distribution is heterogen. This changes can be explained by the variations of microvilli sizes associated by biochimical reactions