Short- and long-term effects of ammonium chloride on RNA, DNA and protein concentrations in muscle and serum in the rainbow trout, Oncorhynchus mykiss.

1. Effects of ammonium-induced acidosis on white muscle RNA, DNA and protein concentrations were examined in the rainbow trout, Oncorhynchus mykiss. Serum protein concentrations were also determined. 2. A single administration of ammonium chloride at a dose of sublethal level caused no changes in these parameters after 3 and 6 hr. 3. Multiple administrations at a lesser dose caused significant decreases in RNA and serum protein concentrations 48 and 72 hr after the first administration. 4. DNA and muscle protein concentrations remained unchanged throughout the experimental period. 5. Significant decreases in RNA-DNA ratios and RNA-muscle protein ratios were primarily attributed to decreases in RNA concentrations.     

Effects of butyrate on cell cycle progression and polyploidization of various types of mammalian cells.

We studied the effect of butyrate on cell cycle progression and polyploidization in three fibroblast (rat 3Y1, human IMR-90, and human embryo lung HEL) and two epithelial (human embryo kidney HEK and monkey kidney BSC-1) cells. In these cells, except for 3Y1, G1 arrest with butyrate was incomplete, and the production of tetraploid cells was detectable in the presence of butyrate. G2 arrest with butyrate was also incomplete in HEL and BSC-1 cells, and the number of HEL cells increased in the presence of butyrate. On the contrary, most BSC-1 cells that divided in the presence of butyrate were unstable and the number of attached cells decreased. These results indicate that the effect of butyrate on cell cycle progression varies with the cell type and that polyploidization can be induced by a single treatment with butyrate.     

Effects of bile acids and lectins on immunoglobulin production in rat mesenteric lymph node lymphocytes

Summary We investigated the effect of bile acids either alone or in combination with lectins on immunoglobulin (Ig) production in vitro of rat mesenteric lymph node (MLN) lymphocytes to examine their immunoregulatory activities. Among free bile acids examined, chenodeoxycholic acid stimulated IgE production by MLN lymphocytes and inhibited IgA production at the concentration of 0.3 mM, whereas cholic and deoxycholic acids exerted the comparable effect at 3 mM. Among conjugated bile acids, deoxycholic acid derivatives stimulated IgE production more strongly than cholic acid derivatives. On the other hand, free and conjugated bile acids did not affect IgG production. The IgE production by MLN lymphocytes was stimulated by concanavalin A and inhibited by pokeweed mitogen, and the effect of phytohemmagglutinin and lipopolysaccharide was marginal. These lectins did not affect IgA and IgG production by the lymphocytes. In the presence of lectins, free bile acids affected IgE production at 0.03 mM. These results suggest the possibility that bile acid is a stimulant for food allergy.     

Serum and liver lipid composition and lecithin: cholesterol acyltransferase in horses, Equus caballus.

1. The lipid composition of serum and liver and some properties of serum lecithin: cholesterol acyltransferase of the horse were investigated. 2. Phospholipids and cholesterol were the major components of serum lipids and the concentration of triglyceride was considerably low. The concentration of liver lipids was comparable with that of other mammals. 3. Fatty acid composition of serum cholesterol ester resembled that of the 2-position of lecithin, except palmitic acid. 4. The activity of serum cholesterol esterifying enzyme was found to be 0.03-0.09 mumol/hr per ml. There was an equimolar decrease in free cholesterol and lecithin during incubation, and changes in unsaturated fatty acids in these two components were in good agreement. 5. Cholesterol esterification was reversibly inhibited by 5,5'-dithiobis-(2-nitrobenzoic acid). The acyl-transferase had a specificity for linoleic acid.