Alkaline Phosphatase Isoenzymes as Related to Physiological Processes

Alkaline Phosphatase Isoenzymes as Related to Physiological Processes 

Many studies in the realm of microbiology (B36, M6, N26, R25) have emphasized the role of substrate and hormone induction of enzymes. It is not surprising, therefore, that similar mechanisms have been searched for, have been found, and are being studied in mammalian systems. 

Beginning with Nitowsky and Herz s observations of quantitative differences between established and recently isolated cell lines (K4) of diverse origins, demonstrations have been published of substrate induction (N23), of induction by osmolarity of the nutrient medium (N25), and of induction by adrenal glucocorticoids (C19, C20, N24). 

Interesting indeed are the recent studies of Griffin and Cox (G20, G21) on the mechanism of adrenocorticoid induction of alkaline phosphatase in human cell cultures. Two temporal phases in the induction of enzyme in HeLa cells are reported a first 12-hour period exhibiting a slow rise in activity, followed by a sudden marked linear increase extending from 15 to 80 hours. The elevation of activity is marked (around 10-fold). The fact that puromycin blocked induction immediately, and actinomycin D 

Human leukocytes possess alkaline phosphatase (L13, 03, RIO, T6, V3, V4) whose activity parallels the concentration of certain circulating steroids. Thus, during the menstrual cycle, the leukocyte alkaline phosphatase evidences a peak at midcycle corresponding to the higher estrogen level. In the later stages of pregnancy the enzyme level increases. Corti-coid hormones also exert an effect on leukocyte alkaline phosphatase. 

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Alkaline Phosphatase Isoenzymes as Related to Physiological Processes. . 316... 

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