The regulation of alkaline phosphatase activity in the duodenum of the mouse from birth to maturity

Abstract

Actinomycin D elevates the alkaline phosphatase activity of the duodenum of the mouse. The effect is relatively slight, but positive, during the first postnatal week, but thereafter becomes marked, not only in the period before the normal maximal level of phosphatase activity is reached at 20 days, but also afterwards, as the activity declines to the adult level. The effect is not manifested in mice at the age of one month, but reappears in adults. Doses of actinomycin that enhance duodenal phosphatase activity depress the activity of the same enzyme in the kidney.Puromycin also increases duodenal phosphatase activity, the effect again being quite small in the first week. At all stages from nine days to adult, however, puromycin strongly elevates activity. Cycloheximide is also effective in raising duodenal phosphatase activity in young mice.Glucocorticoids are known to control the normal developmental increase of phosphatase, but the effect of actinomycin D can be exerted in adrenalectomized mice. The effects of both actinomycin and puromycin are additive with those of hydrocortisone acetate, and both raise phosphatase activity after 15 days, when exogenous corticoids no longer exert any influence.Puromycin stops mitosis in the duodenal epithelium in doses that elevate phosphatase. Hence, some alteration of the enzyme must occur in the striated border of cells that have emerged from the crypts and are in place on the surfaces of the villi. Since the phosphatase-stimulating agents are all inhibitors of protein synthesis, the results are interpreted to mean that duodenal phosphatase normally tends to undergo an activity-enhancing conversion that is restrained by a labile protein.

A System Regulating Alkaline Phosphatase Activity in the Duodenum of the Chick Embryo and Mouse

“…Flexncr et al, 1962). T h a t the quantities used are adequate to produce some inhibition of protein synthesis is however indicated by the fact th a t they generally retard ed increase of body weight or caused weight loss, strongly reduced kidney phos phatase activity, and lowered spleen weight (Moog, 1966). The pro tein concentration of the duodenum in m ost cases decreased slightly, b u t th e effect was rarely of statistical significance.…”

Spatial and Temporal Differentiation of Alkaline Phosphatase on the Intestinal Villi of the Mouse

“…supported by the finding that actinomycin D, puromycin, and other drugs that interfere with the synthesis of RNA or protein bring about an elevation of phosphatase activity not only in developmental stages, when phosphatase normally rises (19), but also in adults, when a constant level ordinarily is maintained (20). Since puromycin exerts an activity-enhancing effect under conditions of complete suppression of mitosis, the elevation of phosphatase activity does not depend on the production of new cells (20).…”

“…Since puromycin exerts an activity-enhancing effect under conditions of complete suppression of mitosis, the elevation of phosphatase activity does not depend on the production of new cells (20).…”

Induction of chick embryonic intestinal disaccharidases by hydrocortisone and sucrose in the organ culture system.

“…In this system, it is clearly demonstrated that hydrocortisone acts on the synthesis of enzyme protein via mRNA synthesis and tryptophan decreases the degradation of enzyme (15,16).…”