Histochemical studies on fat absorption in the jejunal mucosa after total pancreatectomy in dog

Abstract

Histologic and histochemical changes in the jejunal mucosa were investigated to clarify the pathogenesis of the disturbances of digestion and absorption and the effect of estrogen on absorption after total pancreatectomy in dogs. Histologic Changes. The crypts of Lieberkühn in the jejunal mucosa were slightly lengthened, but a decrease in the absorptive surface due to villous atrophy was not observed after total pancreatectomy. Fat Absorption. The jejunal epithelium contained little or no Sudan-positive material in normal dogs fasting 24 hours, but lipid droplets stained with Sudan III were sometimes found in the absorptive epithelium and occasionally in the central lacteals in pancreatectomized dogs treated with insulin alone. When estrogen was administered together with insulin, lipid droplets were not observed in the epithelial cells or central lacteals, as in the control dogs. After oral administration of olive oil or oleic acid, absorbed lipid droplets were not observed in the jejunal mucosa of dogs treated with insulin alone after total pancreatectomy, but when estrogen was administered together with insulin, numerous lipid droplets appeared in the jejunal mucosa after oral administration of oleic acid, although olive oil was not absorbed. After the administration of medium chain triglycerides, a few lipid droplets were found in the absorptive epithelium at the tip of the villi, but estrogen did not have any effect on absorption. Changes of Enzyme Activity. Adenosine triphosphatase, alkaline phosphatase, and succinic dehydrogenase activities decreased markedly in the absorptive epithelium in dogs treated with insulin alone after total pancreatectomy. When estrogen was administered together with insulin after total resection of the pancreas, the activities of these enzymes in the epithelial cells were restored to normal. The results reported here show (1) that there is not only a disturbance in fat digestion but a definite impairment in fat absorption after total pancreatectomy, (2) that the disturbance in fat absorption can be attributed to the decreased activity in the epithelium of such enzymes as adenosine triphosphatase, alkaline phosphatase, and succinic dehydrogenase, and (3) that the activities of these enzymes are restored by estrogen administration, accompanied by an improvement in the absorption of fatty acids.