Vitamin D-regulated, ATP-dependent calcium transport by intestinal Golgi vesicles during maturation in the rat.

The developmental aspects of calcium uptake by intestinal Golgi vesicles was determined using highly purified Golgi vesicles from enterocytes of suckling (2 wk old), weanling (3 wk old), and adolescent (6 wk old) rats. Calcium uptake by Golgi vesicles at all age groups represented transport into the intravesicular space as evident by temperature dependency and by calcium ionophore A23187-induced calcium efflux studies. Calcium uptake was driven by ATP at all age groups, however, maximal uptake at 15 min was significantly greater in Golgi vesicles of adolescent rats compared to mean values in Golgi vesicles of suckling rats (p less than 0.

Inhibitors of cytochrome P-450-dependent arachidonic acid metabolism.

A new generation of heteroatom analogs of arachidonic acid are documented as powerful and selective inhibitors of the cytochrome P-450-dependent arachidonic acid oxygenase reaction (IC50, 5-10 microM) with little effect on either cyclooxygenase or soybean lipoxidase at 100 microM. The imidazole derivatives, ketoconazole and clotrimazole, are potent and selective inhibitors of the arachidonic acid epoxygenase and lipoxidase-like activities of phenobarbital-induced rat liver microsomal fractions (IC50, 2.0 and 0.

NADPH-dependent microsomal metabolism of 14,15-epoxyeicosatrienoic acid to diepoxides and epoxyalcohols.

The arachidonic acid epoxygenase metabolite 14,15-epoxyeicosatrienoic acid is further metabolized by rat liver microsomal fractions to regioisomeric diepoxides and epoxyalcohols. Diepoxides result from epoxidation at the 5,6-, 8,9-, or 11,12-olefins. Hydroxylation leading to epoxyalcohols with a cis, trans-conjugated dienol occurs at carbons 5, 8, 9, or 12.

Active calcium transport by intestinal endoplasmic reticulum during maturation.

Calcium uptake by intestinal endoplasmic reticulum was determined during maturation in the rat. Calcium uptake was enhanced severalfold by the presence of ATP in suckling, weanling, and adolescent rats. Uptake values were higher during early life and decreased gradually with age.