Effect of fat feeding on intestinal alkaline phosphatase activity in tissue and serum

Abstract

Serum intestinal alkaline phosphatase activity is increased by fat feeding, but the mechanism of this increase is not fully understood. Fasting rats were fed a single feed of either corn oil (12 kcal) or an isocaloric elemental feed (Vivonex 100 HN). Changes in enzyme activity in the small bowel mucosa and serum were followed for 20 h. Only the fat-fed rats had increased serum enzyme activity, being maximal at 7 h and three times the fasting level. This resulted from an increase in the amount of enzyme protein in the serum and not from an increase in its catalytic efficiency. The serum biological half-life of 125I-labeled intestinal alkaline phosphatase was the same in fasted (2.51 min) and fat-fed rats (2.55 min). Both types of feed caused a quantitatively similar increase in brush-border-bound alkaline phosphatase activity. However, levels of soluble intracellular alkaline phosphatase in intestinal mucosa were affected differently: the elemental diet caused a substantial rise, whereas no significant change was seen after fat feeding. The isoelectric pattern of phosphatase activity in serum after fat feeding was identical to that of soluble intracellular and not membranous alkaline phosphatase. Therefore, serum intestinal alkaline phosphatase activity rises in response to a single fat feed as a result of increased delivery of the enzyme to the blood and not as a result of an increase in its normally short biological half-life. This rise cannot be directly linked to an increase in the amount of brush-border-bound enzyme, and it appears that the serum enzyme is derived directly from a pool of soluble intracellular enzyme in the small bowel mucosa.

Polyphenol-enriched oolong tea increases fecal lipid excretion

“…The serum ALP levels elevate in healthy humans or animals when lipids are administered in a test meal or a high-lipid diet is consumed (McDowell and Ross, 1966;Young et al, 1981;Deems et al, 1994). On the other hand, polyphenolic compounds have been shown to inhibit iron absorption (Zijp et al, 2000;Samman et al, 2001).…”

Arabinoxylan Fiber from a By-Product of Wheat Flour Processing Behaves Physiologically like a Soluble, Fermentable Fiber in the Large Bowel of Rats

“…ALP and DPPIV activities were assayed spectrophotometrically using p-nitrophenyl phosphate and glycyl-L-proline-p-nitroanilide (Sigma-Aldrich, St. Louis, MO), respectively, as substrates (Maroux et al 1973, Young et al 1982. Enzyme activities were expressed relative to the mucosal protein content, which was determined using bovine ␥-globulin as a standard (Bradford 1976).…”

Intestinal alkaline phosphatase release is not associated with chylomicron formation

“…Since then, numerous investigators (5,6,15,19,29,32) have confirmed this phenomenon. On the other hand, a carbohydrate or protein meal is incapable of stimulating IAP (3,12).…”