Thymus involution induced by 5-azacytidine.
Hypomethylation of DNA, which can be achieved by incorporation of 5-azacytidine, has been correlated with derepression of genes. In order to examine the in vivo effects of 5-azacytidine on organ development and differentiation, young rats were treated with the drug. There was an almost complete reduction of thymus and a marked reduction of spleen weight, while other organs, including testes were only marginally affected. Control experiments with cytosine-arabinoside suggest that treatment with an inhibitor of DNA replication per se is not responsible for the very rapid thymus involution triggered by 5-azacytidine in rats. In spite of the drastic reduction of thymus and spleen weight, lymphocytes of these organs were not impaired in their response to the T cell mitogen Concanavalin A.
D000818:Animals; D001374:Azacitidine / Q000633:toxicity*; D003561:Cytarabine / Q000633:toxicity*; D004261:DNA Replication / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D007700:Kinetics; D008297:Male; D009929:Organ Size / Q000187:drug effects; D051381:Rats; D011919:Rats, Inbred Strains; D013950:Thymus Gland / Q000187:drug effects / Q000473:pathology*
D003561:Cytarabine; D001374:Azacitidine