title: [Pulse cytophotometrical investigations about the resistance of DNA against acid hydrolysis influenced by ageing and cortisol (author's transl)].
abstract: The resistance of nuclear chromatin against acid hydrolysis with hydrochloric acid was studied in cell nuclei of different organs from young and old rats and after application of cortisol. Suspensions of cell nuclei from liver, spleen, kidney, heart muscle and mucosa from small intestine were stained with ethidium bromide without and after hydrolysis. The relative fluorescence intensity (FI) of every pair was measured by flow through cytophotometry. Always the FI of the diploid peaks of the hydrolysed samples was diminished. The resistance against hydrolysis was greater in old animals than in young. After application of cortisol in vivo in all organs, except in the liver, the resistance against hydrolysis was increased. Only the nuclei of liver from old animals showed a diminution of resistance after cortisol. It is assumed, that the greater resistance in age is due to the diminished functional ability of the nuclear chromatin. In the most organs, the inhibitory activity of cortisol to the cell metabolism is known, only in the liver cell it stimulates the synthesis of RNA and protein. This is in agreement with our findings.
mesh_terms: D000375:Aging; D000818:Animals; D002843:Chromatin / Q000187:drug effects*; D003584:Cytological Techniques; D004247:DNA / Q000378:metabolism*; D004351:Drug Resistance; D006851:Hydrochloric Acid / Q000494:pharmacology*; D006854:Hydrocortisone / Q000494:pharmacology*; D006868:Hydrolysis; D009928:Organ Specificity; D010783:Photometry; D051381:Rats
chemical_list: D002843:Chromatin; D004247:DNA; D006851:Hydrochloric Acid; D006854:Hydrocortisone
vernacular_title: Impulscytophotometrische Untersuchungen der DNS-Säureresistenz unter Einfluss von Alter und Cortisol.