Hydrocortisone, alkaline phosphatase

Regulation of alkaline phosphatase activity was discussed by Cox and Griffin 65). Steroids such as hydrocortisone or prednisolone (1 (ig/ml of medium) can induce a 3- to 20-fold rise in certain HeLa cell cultures, while other cell lines are induced by 15 mM phenyl phosphate. Recently, it has been shown that fibroblast cell cultures are also stimulated by prednisolone (( ( ). According to one report, Pi may have a control function here a decrease in the level of rat kidney P produced by a low phosphate diet was accompanied by an increase in alkaline phosphatase. Nine other enzymes monitored were unaffected 67). 

Recently Watson et al. have demonstrated intestinal alkaline phosphatase level is normally under adrenal control (W7a). Hydrocortisone administration produced large increases in intestinal alkaline phosphatase activity. 

Some physiological or pathological stimuli induce the liver cell to synthesize or break down some protein selectively. Even during starvation the content of all liver protein does not drop simultaneously. For example, while the activities of catalase, xanthine oxidase, alkaline phosphatase, and acid phosphatase drop at various rates as starvation progresses, that of glucose-6-phosphatase increases. Hydrocortisone and tryptophan administration induces a massive increase in tryptophan peroxidase activity. In either case, at least part of the increase in enzyme activity results from de novo enzyme synthesis. If tryptophan administration is interrupted, the activity of the peroxidase returns to normal. During the induction, turnover rates of other proteins do not change. 

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