Summary. Carnitine metabolism is altered in renal insufficiency and influenced by the treatment modalities. Chronically uremic patients with end-stage renal disease under conservative therapy, hemodialysis, or peritoneal dialysis show low, normal, or elevated serum levels of TC and a distorted pattern of FC, SCAC, and LCAC. HD induces a marked depletion of FC, while predialytic elevated SCAC and LCAC are in the normal range at the end of dialysis treatment. All carnitine fractions rapidly return to predialysis levels 6 h after HD due to a transport of carnitine from muscle stores to plasma pool. Muscle carnitine content is elevated in chronic uremic patients under conservative therapy. Normal or decreased levels are observed in patients on long-term HD treatment. In addition, weekly losses of carnitine in patients undergoing HD or peritoneal dialysis do not exceed urinary carnitine excretion of CO. Supplementation with currently recommended doses (1-2 g L-carnitine i.v. at the end of each HD) is followed by a marked rise in plasma carnitine levels, suggesting limited carnitine utilization in uremia. Therefore, lower carnitine doses and modified application regimens should be considered to avoid exaggerated plasma levels of carnitine and carnitine esters. Furthermore, carnitine application has been reported to show beneficial, worsening, or no effect on the deranged lipid metabolism of the uremic patients. In patients undergoing CAPD or IPD predominantly normal serum carnitine levels have been
Cell suspension cultures of parsley and soy- bean were incubated for 38 h with 14C-labeled ben- zo(a)pyrene; autoclaved cultures were used as con- trols. Metabolites were isolated by a sequential extrac- tion procedure and further studied by chromatog- raphy or by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate. The soluble metabolites amounted to 1-2.2% in the case of parsley cells, and 19-28% in the case of soybean cells. These metabolites varied in polarity, some being solu- ble in organic solvent or aqueous buffer while other metabolite fractions were soluble only in hot aqueous sodium dodecylsulphate. In addition, a significant amount of an insoluble metabolite fraction was iso- lated from the culture fluid as well as the cellular material of soybean suspension cultures.
