Differential recovery of intestine, bone marrow, and thymus of rats with solid tumors following 5-fluorouracil administration.
Time relationships for recovery of several host organs from toxic effects of 5-fluorouracil were determined in ACI rats bearing Morris hepatoma 3924A. A single injection of 150 mg/kg body weight 5-fluorouracil (the LD10) resulted in loss of 90% of the tibial bone marrow, 60% of the intestinal mucosa, and 90% of the thymus as measured by total DNA content of the organs. Organ DNA contents following 150 mg/kg of the drug were minimal on day 3 for intestine and on day 5 for marrow and thymus. A return to pretreatment or higher levels of DNA was observed by day 4 for intestine, day 11 for tibial marrow, and day 19 for thymus. Incorporation of 3H-deoxyuridine into host organ DNA after 150 mg/kg 5-fluorouracil was inhibited 36 hrs for intestine, 3 days for thymus, and 5 days for tibial bone marrow. Inhibition of 3H-deoxyuridine incorporation into DNA was similar for 50, 100, and 150 mg/kg doses both in tumor and in host organs, but recovery of 3H-deoxyuridine incorporation and DNA content of host organs began later with the higher doses of 5-fluorouracil. Maximal incorporation of 3H-deoxyuridine into DNA was observed on day 4 for intestine, day 8 for marrow, and day 9 for thymus after treatment with 150 mg/kg 5-fluorouracil. Animal lethality following the second of two 150 mg/kg injections of 5-fluorouracil was related to the extent of recovery of intestinal mucosa and bone marrow at the time of the second injection. Survival decreased to 0% for normal rats when the interval between injections was 3-4 days, improved at 5 days and was 100% when the interval was 10-11 days.
D000818:Animals; D001853:Bone Marrow / Q000187:drug effects* / Q000378:metabolism; D006528:Carcinoma, Hepatocellular / Q000188:drug therapy / Q000378:metabolism; D004247:DNA / Q000096:biosynthesis; D003857:Deoxyuridine / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D005260:Female; D005472:Fluorouracil / Q000494:pharmacology*; D007413:Intestinal Mucosa / Q000187:drug effects* / Q000378:metabolism; D008113:Liver Neoplasms / Q000188:drug therapy / Q000378:metabolism; D009374:Neoplasms, Experimental; D051381:Rats; D011912:Rats, Inbred ACI; D013950:Thymus Gland / Q000187:drug effects* / Q000378:metabolism; D013977:Tibia; D013997:Time Factors
D004247:DNA; D005472:Fluorouracil; D003857:Deoxyuridine