THE ABSORPTION OF FAT BY INTESTINE OF GOLDEN HAMSTER IN VITRO

Abstract

Evcrtcd sacs of intestine from golden hamsters were incubated at 37°C for at lcast 1 hour in vitro with emulsified lipid after removal of both pancreatic lipase and bile salts. The fine structure of intestinal epithelium is wcll preserved under these conditions. Absorption of fat by the intestinal mucosa in vitro closely resembles lipid absorption in vivo, as observed by both light and electron microscopy. ~he physiological significance of these observations is discussed. Tubular elements of the agranular endoplasmic reticulum are often strikingly abundant in the apical cytoplasm of intestinal absorptive cells. These have a role in the intracellular transport of fat since they frequently contain droplets of lipid derived from the incubation medium. The ratc of fat accumulation in the epithelium appcars to be proportional to the concentration in the medium.

Fine Structure of Gut Epithelial Cells of Larval and Juvenile Carp During Absorption of Fat and Protein

“…One of these, which has been deduced from electron microscopy is that the absorptive cells take up fat droplets by a process of pinocytosis (PALAY and KARLIN, 1959;MILLINGTON and FINEAN, 1963;STRAUSS, 1963;PALAY and REVEL, 1964). However, none have demonstrated vigrorous pinocytotic activity enough to explain the rapid absorption of large amounts of fat.…”

The in vitro transfer of bovine immune lactoglobulin across the intestine of new‐born pigs

“…Protein is believed to enter mucosal cells by a process of pinocytosis (Clark, 1959), and Strauss (1963) Brambell, Halliday & Morris (1958) suggest that the process of pinocytosis would not be selective, that receptors within pinocytotic vesicles selectively bind the immune protein and that this protects the antibody from intravesicular digestion. Interference is then explained on the basis of competition occurring between similar but not identical molecules for a common receptor within the pinocytotic vesicle.…”

Organ culture of mucosal biopsies of human small intestine

“…Many short-term experiments (2 hr or less) have been satisfactorily conducted by maintaining open intestinal segments or everted rings and sacs of intestinal tissue in suitable oxygenated buffer solutions (1,2). Careful morphological studies have shown that epithelial cell integrity is maintained in these short-term experiments (3)(4)(5). However, marked epithelial cell necrosis and disintegration occurs if incubation of intestinal tissue is prolonged much beyond 2 or 3 hr.…”