When rat endometrial stromal cells from uteri sensitized for decidualization are cultured in vitro, there is an increase in alkaline phosphatase (ALP) activity paralleling that seen in vivo during decidualization. The addition of indomethacin to the culture medium decreases the endogenous production of prostaglandin E2 (PGE2) to below detectable levels and substantially reduces the increase in ALP activity. The addition of either PGE2 or its analog 16,16-dimethyl-PGE2, but not PGF2 alpha or its analog 15(S),15-methyl-PGF2 alpha, overrides this inhibitory effect, suggesting that PGE2 has a specific stimulatory effect upon ALP activity. This in vitro system was used to investigate the role of the cAMP pathway in mediating the stimulatory effect of PGE2 on ALP activity. The data indicate that PGE2 causes an increase in cAMP accumulation by the cells and that the addition of an analog of cAMP or substances which increase the level of cAMP in the cells (1-methyl-3-isobutyl xanthine, cholera toxin, forskolin) causes an increase in ALP activity. Collectively, the results suggest that the stimulatory effect of PGE2 is at least partially mediated by the cAMP pathway.

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Superoxide dismutase has been found to be widely distributed and of approximately the same specific activity in all regions of human brain examined. It is not reduced during degeneration of the basal ganglia in Huntington's Chorea. After subcellular fractionation of human and guinea-pig cerebral cortex, the highest specific activity of the enzyme was found in the soluble fraction.