Sex differences in hepatic sulfation of taurolithocholate in the rat

Metabolism of the bile salts by formation of sulfate esters is catalyzed by bile salt sulfotransferase, an enzyme isolated from rat liver and kidney. The activity of bile salt sulfotransferase was measured in liver and kidney of male and female rats and in oophorectomized rats with or without estrogen replacement. In vitro sulfotransferase activity was correlated with in vivo sulfation by measuring the percentage of an infused dose (0.03 micron per 100 g per min) of taurolithocholate, which was excreted in bile as the sulfate. The activity of sulfotransferase in liver was higher in females (26.3 +/- 3.0 pmoles per mg of protein per min) than in males (9.6 +/- 3.9) and was lower (12.1 +/- 3.8) after oophorectomy. The decrease in activity was prevented by replacement of estrogen. Renal sulfotransferase activity did not differ between the sexes and was unaffected by oophorectomy. Hepatic sulfotransferase activity measured in vitro correlated with in vivo sulfation of taurolithocholate. This study shows definite sex differences in hepatic bile salt sulfotransferase activity, which in females is affected by the presence of estrogen. The correlation between in vitro sulfotransferase activity and in vivo bile salt sulfation suggests that bile salt sulfotransferase is responsible for bile salt sulfation in vivo.     

Lymphocyte and macrophage responses after vaccinia virus infections

Using a semimicromethod with washed whole blood, in vitro lymphocyte responses of rabbits to intradermal infection with vaccinia virus was studied. Peritoneal exudate macrophages were infected with vaccinia in vitro to determine the time of appearance of activated macrophages. After primary infection, an increase in spontaneous incorporation of thymidine by blood cultures was found as early as 2 days postinfection. This effect was at a maximum at 7 to 10 days, with counts up to 100-fold higher than before infection. Incubation of these cultures with concanavalin A showed a marked decrease in stimulation index as compared with normals. Although only a transient stimulation with vaccinia was found during the acute infection, stimulation indexes of 2 to 3 were obtained during convalescence. Macrophages from rabbits early after infection supported vaccinia replication, whereas those at day 6 or later resisted infection. Macrophage resistance persisted for 2 to 3 weeks. The response of lymphocytes from rabbits reinfected with vaccinia after 15 weeks differed, with a small increase in spontaneous thymidine uptake, a smaller depression in concanavalin A stimulation, and a greater specific response to vaccinia. Macrophage activation occurred earlier and persisted for a longer time after secondary infection.     

Effect of high dietary zinc upon zinc metabolism and intracellular distribution in cows and calves

Changes in the metabolism of zinc were investigated in mature nonlactating Holstein cows and 4-mo old calves fed high but nontoxic amounts of dietary zinc. Increasing dietary zinc of calves from 42 to 642 ppm elevated the zinc content of liver and pancreas 600% and 1400%, respectively. The elevated zinc in liver and pancreas involved a substantial increase in all intracellular fractions, with by far the largest amount associated with a 10,000 molecular-weight protein in the soluble cell fraction. This zinc-binding protein may protect the cell against damage from increased zinc. A comparable increase in dietary zinc of mature cows did not affect zinc content of liver or kidney nor alter the intracellular distribution of zinc in the liver. In mature cows, homeostatic control mechanisms which regulate the zinc content of tissue are much more effective than in calves. Accordingly, mature cows probably are able to tolerate higher concentrations of dietary zinc.     

Life change, its perception and alcohol addiction

Alcohol addiction was associated with high life change and an attenuated perception of life change. The possible association of these factors with the perpetuation of the addiction is discussed.     

Lysosomal enzyme activities in parenchymal and nonparenchymal liver cells isolated from young, adult and old rats

Parenchymal and nonparenchymal cells were isolated from the livers of female BN/BiRij rats, aged 3, 12, 24 and 30-35 months, by means of enzymatic techniques. About 70% of the cells in the nonparenchymal cell suspensions were endothelial cells and 25% were Kupffer cells. More than 90% of the isolated parenchymal, Kupffer and endothelial cells were viable as judged by trypan blue exclusion and ultrastructural appearance. The age-related changes in the specific activities of the lysosomal enzymes acid phosphatase, beta-galactosidase, cathepsin D and arylsulphatase B in parenchymal and nonparenchymal cells showed no correlated behavior. The most prominent change was observed for the cathepsin D activity in parenchymal cells, which nearly triples during the lifespan of the rat. A comparison of the activities obtained with homogenates of the whole liver and with parenchymal and nonparenchymal cells revealed that aging changes in lysosomal enzyme activities in homogenates should be carefully interpreted, since opposite patterns of change were often observed in the activities in parenchymal cells and in nonparenchymal cells.