Changes in Sucrase, Enterokinase, and Peptide Hydrolase after Intestinal Resection THE ASSOCIATION OF CELLULAR HYPERPLASIA AND ADAPTATION

Abstract

A B S T R A C T In a study of changes in digestive enzymes after massive intestinal resection and the mechanisms by which such changes occur, rats were sacrificed 4 wk after removal of the proximal two-thirds of the small intestine. Alterations in the mucosal levels of sucrase, enterokinase, and dipeptide hydrolase (Lleucyl-L-alanine substrate) were examined in the light of associated changes in protein, DNA and wet mucosal weight, measured in standardized gut segments from various regions of intestine.Metabolic studies showed that normal growth patterns were reestablished after the operation but significant elevations in stool weight and fecal nitrogen occurred in the second postoperative week, falling towards normal by the 4th wk. In standard gut segments wet weight of mucosa, protein, and DNA rose, especially in distal segments, DNA increasing disproportionately. Mucosal levels of the proximally distributed and membranebound enzymes, sucrase and enterokinase, showed similar patterns of change: when enzyme activity was expressed in terms of the total per segment, proximally there were considerable increases in both enzymes, but, expressed in terms of specific activity, that of sucrase fell and that of enterokinase was unaltered. By contrast, the largely soluble and more distally distributed dipeptide hydrolase increased more in distal segments and the increases in total activity were accompanied by lesser increases in specific activity. However, in spite A preliminary report of this work was presented to The

Effect of nitrogen source on nutritional management after small bowel resection in rats.

“…One of the interesting characteristics of the diets is that the diets are composed of simple or elemental form of nutrients which minimize the digestive process. The other is that the diets contain no indigestible bulk of fibrous materi als which leads to striking diminution in fecal excretion (15,17). All the diets used in the present study contained no cellulose component.…”

“…McCARTHY and KIM (15) found in the proximally resected rats that significant elevation in fecal excretion occurred in the second postoperative week, falling towards normal by the fourth week. NYGAARD (11) reported with a laboratory chow containing 23% of crude protein and 2.6% of fat that fecal nitrogen excretion did not change by 25% distal resection, but increased progressively as the extent of small bowel resected was larger.…”

“…Disappearance of diarrhea seemed to be in accord with development of hyperplasia in intestinal remnant. Regarding hyperplasia, it is known that the intestinal remnant after resection undergoes mucosal hyperplasia, particularly in the ileal remnant after proximal resection (12,15,16). Past experiments did not make it clear when adaptive hyperplasia occurred in the intestinal remnants since the measurements of intestinal remnants were made after a considerably longer time following resection.…”

Adaptive Changes of Sugar Absorption in Rat Small Intestine during Fasting and Refeeding

“…Many studies have shown that rapid alterations in mucosal functions are observed in response to the composition of diet [1], fasting [2], total parenteral nutrition [3], intestinal resection [4], or diabetes mellitus [5,6]. However, the mechanisms regulating the adaptation of intestinal absorption are incompletely understood.…”

Intestinal brush border membrane enzyme activities of rats fed chemically defined diets containing oligopeptides or amino acids as the nitrogen source.

“…Preparation of cytosol fraction. The cytosol fractions were obtained by the method of MacCarthy and Kim [ 11 ] from the intestinal mucosa at the same sites described above from rats fed experimental diets for 1 week or 1 month. The mucosa was homogenized in 14% glycerol and centrifuged (Type 70P-72, Rp55T rotor, Hitachi Koki Co., Tokyo) at 45,000 X g for 1 h at 0°C.…”