title: The toxicity, distribution and excretion of ricin holotoxin in rats.
abstract: The distribution and excretion of the plant toxin ricin were studied in rats after intravenous injection. 125I-labelled ricin was equal in toxicity to native ricin. Following injection, the liver was the major organ of localisation - 46% of injected dose at 0.5 h. The spleen and muscle were next with 9.9% and 13%, respectively, at 0.5 h. Ricin was relatively concentrated in the spleen (33% of injected dose/g of tissue) compared with the liver (7.4%/g) and the bone marrow (5.5%/g). The concentration in the lymph nodes was very low (1.2%/g). Ricin was quickly cleared from the animal; only 11% of the initial radioactivity remained 24 h later with 70% excreted in the urine. Excretion into the intestine via the bile duct was less than 5% by 24 h, 10-12% of the radioactivity was found in the intestinal contents or intestinal wall between 3 h and 12 h, and much of this was reabsorbed since less than 2% was recovered in faeces.
authors.affiliation: Department of Cell and Structural Biology, Medical School, University of Manchester, U.K.
authors.forename: C S
authors.initials: CS
authors.lastname: Ramsden
authors.forename: M T
authors.initials: MT
authors.lastname: Drayson
authors.forename: E B
authors.initials: EB
authors.lastname: Bell
mesh_terms: D000818:Animals; D001652:Bile Ducts / Q000378:metabolism; D001692:Biological Transport; D001853:Bone Marrow / Q000378:metabolism; D007275:Injections, Intravenous; D007413:Intestinal Mucosa / Q000378:metabolism; D007668:Kidney / Q000378:metabolism; D008099:Liver / Q000378:metabolism; D008214:Lymphocytes / Q000378:metabolism; D009132:Muscles / Q000378:metabolism; D051381:Rats; D012276:Ricin / Q000493:pharmacokinetics / Q000633:toxicity* / Q000652:urine; D013154:Spleen / Q000378:metabolism; D013997:Time Factors
chemical_list: D012276:Ricin