ABSTRACT
The effects of cortisol on protein metabolism were examined in rhabdomyosarcoma tissue, experimentally provoked in rats by a single intramuscular injection of cobalt powder into the adductor muscle of the hind limb. In vivo treatment of tumour bearing animals with 1 and 10 mg cortisol resulted in a reduced incorporation of [2-14C] glycine into the tumour proteins. In vitro application of 0.01 to 100 micrograms cortisol on tumour slices equally reduced the amino acid incorporation into the proteins. These inhibitions could not be explained by modifications in protein, RNA, DNA content or by changes in the membrane function. The factors inhibiting the amino acid incorporation into tumour proteins could be located in the 105,000 X g supernatant protein fraction. The tumour transfer RNA methylase activity became markedly inhibited by cortisol treatment.
Subject(s)
Hydrocortisone/pharmacology , Neoplasm Proteins/metabolism , Rhabdomyosarcoma/metabolism , tRNA Methyltransferases/metabolism , Animals , DNA, Neoplasm/metabolism , Glycine/metabolism , In Vitro Techniques , Male , Neoplasms, Experimental/metabolism , RNA, Neoplasm/metabolism , RatsABSTRACT
Methods for the determination of paraquat are reviewed. Procedures are described in detail for the determination of paraquat in diverse materials such as food stuffs, body fluids, and water. The recommended procedures include visual spot test, spectrophotometric, gas chromatographic, and high performance liquid chromatographic techniques.
Subject(s)
Paraquat/analysis , Chromatography, Gas , Chromatography, High Pressure Liquid , Colorimetry , Food Analysis , Humans , Paraquat/urine , Water Pollutants, Chemical/analysisABSTRACT
Collagen metabolism in rat skin and the response to X-radiation are studied during three consecutive hair-cycles. Collagen biosynthesis and turnover, assessed by the hydroxylation of [U-14C]-proline, proceeds as a function of the periodic hair-growth phenomenon. A single X-radiation treatment to the skin does not affect the amino-acid composition of collagen, but reduces the proline hydroxylation capacity of the fibroblasts. The initial damage to the tissue, resulting in a reduced collagen concentration of the skin, particularly noticeable after several hair-cycles, is at least partially responsible for the delayed skin lesions after irradiation.
