DEVELOPMENT OF GASTROINTESTINAL FUNCTIONS

Data are summarized about digestion and absorption of carbohydrates, l ipids and proteins during mammalian perinatal development including hu man fetuses. Corresponding with the high fat intake in suckling rats, absorption of triglycerides was found to be approximately 2-3 times hi gher in suckling than in adult rats. Carnitine contents of the small i ntestinal mucosa of rats decrease postnatally, reaching adult levels a t the time of weaning. Other studies suggested that gluconeogenesis ma y occur In the small intestine in the neonatal period. The intestinal mucosa of infant rats produces ketones; it was suggested that ketone p roduction is to a large extent due to a breakdown of long-chain fatty acids. Studies dealing with the development of colonic sodium transpor t in rats are described. Other studies on the developing colon showed that the proximal colon resembles ileum during the early postnatal per iod. Developmental changes of the ''specialization'' of intestinal seg ments are reviewed. In all studies attention is given to the maturativ e effects of hormones of the adrenal cortex and thyroid gland (88 refe rences).