title: Reduction in responsiveness of thymocytes to phytohemagglutinin during bladder tumor induction and restorative effects of thymosin fraction 5 in rats.
abstract: Urinary bladder tumors were induced in female Wistar rats by oral administration of N-butyl-N-(4-hydroxybutyl) nitrosamine [(BBN) CAS: 3817-11-6]. Hypertrophy or vascular formation was observed in the bladder membrane 8 weeks after BBN administration, and tumors became visible at the 15th week. At the 20th week, approximately 95% of these rats had bladder tumors. The response of thymus lymphocytes to phytohemagglutinin (PHA) in these BBN-treated rats began to decrease from the 10th week and decreased significantly from the 18th week as compared with that in untreated rats. This reduced response to PHA was slower in comparison with the reduced response to concanavalin A. When thymus lymphocytes were preincubated with thymosin fraction 5 in vitro, the response to PHA improved between the 8th week and the 20th week. Furthermore, when the thymus small lymphocyte population was separated into 3 subpopulations by discontinuous density gradient centrifugation and adhesion column, the restorative effect of the thymus hormonal product was greater in the intermediate and heavier subpopulations.
mesh_terms: D000818:Animals; D002085:Butylhydroxybutylnitrosamine; D005260:Female; D008213:Lymphocyte Activation; D010835:Phytohemagglutinins / Q000494:pharmacology; D011230:Precancerous Conditions / Q000139:chemically induced / Q000276:immunology; D051381:Rats; D011919:Rats, Inbred Strains; D013601:T-Lymphocytes; D013947:Thymosin / Q000031:analogs & derivatives* / Q000494:pharmacology; D013950:Thymus Gland / Q000166:cytology; D013997:Time Factors; D001749:Urinary Bladder Neoplasms / Q000139:chemically induced / Q000276:immunology*
chemical_list: D010835:Phytohemagglutinins; C033782:thymosin fraction 5; D002085:Butylhydroxybutylnitrosamine; D013947:Thymosin