Table 3

Concentration of radioactivity in different rat tissues after administration of a single i.v. dose of 75 mg/kg [¹⁴C]monochloroacetic acid

Tissue	Percentage of Dose per Gram of Tissue or Total in Excreta and GI Tract
Tissue	5 min	15 min	45 min	2 h	4 h	8 h	16 h	Dead^3-a
Plasma_{(total [} _¹⁴ _C]MCA)	1.04 ± 0.01^3-b	0.64 ± 0.01	0.56 ± 0.01	0.39 ± 0.01	0.13 ± 0.01	0.04 ± 0.004	0.02 ± 0.003	0.59 ± 0.06
Plasma_{(parent MCA)}	0.83 ± 0.02	0.47 ± 0.02	0.45 ± 0.02	0.25 ± 0.04	0.09 ± 0.01	0.03 ± 0.002	0.02 ± 0.004	N.D.
Liver	0.90 ± 0.01	0.97 ± 0.03	0.87 ± 0.03	0.64 ± 0.04	0.43 ± 0.03	0.33 ± 0.04	0.17 ± 0.04	0.58 ± 0.02
Kidney	0.76 ± 0.02	0.79 ± 0.02	1.03 ± 0.03	1.29 ± 0.09	1.58 ± 0.12	0.41 ± 0.05	0.16 ± 0.05	0.70 ± 0.02
Heart	0.66 ± 0.02	0.52 ± 0.01	0.51 ± 0.01	0.35 ± 0.02	0.21 ± 0.01	0.08 ± 0.01	0.04 ± 0.001	0.42 ± 0.02
Brain	0.40 ± 0.01	0.38 ± 0.01	0.43 ± 0.01	0.36 ± 0.02	0.28 ± 0.01	0.26 ± 0.01	0.26 ± 0.03	0.42 ± 0.02
Thymus	0.50 ± 0.01	0.40 ± 0.01	0.45 ± 0.01	0.67 ± 0.01	1.01 ± 0.03	1.02 ± 0.04	0.52 ± 0.02	0.35 ± 0.01
Brown fat	0.65 ± 0.01	0.52 ± 0.01	0.62 ± 0.05	0.75 ± 0.09	0.57 ± 0.04	0.22 ± 0.04	0.07 ± 0.004	0.34 ± 0.02
White fat	0.21 ± 0.01	0.17 ± 0.02	0.18 ± 0.01	0.20 ± 0.02	0.22 ± 0.01	0.13 ± 0.02	0.03 ± 0.002	0.27 ± 0.02
Lungs	0.52 ± 0.01	0.39 ± 0.01	0.39 ± 0.01	0.31 ± 0.01	0.18 ± 0.004	0.11 ± 0.01	0.06 ± 0.01	0.35 ± 0.01
Testis	0.27 ± 0.01	0.33 ± 0.01	0.43 ± 0.01	0.41 ± 0.02	0.38 ± 0.02	0.30 ± 0.02	0.19 ± 0.03	0.56 ± 0.05
Spleen	0.47 ± 0.01	0.36 ± 0.01	0.37 ± 0.01	0.39 ± 0.02	0.44 ± 0.01	0.27 ± 0.03	0.08 ± 0.01	0.53 ± 0.02
Muscle	0.43 ± 0.01	0.30 ± 0.01	0.25 ± 0.01	0.17 ± 0.01	0.08 ± 0.003	0.06 ± 0.001	0.05 ± 0.003	0.49 ± 0.02
Skin (ears)	0.76 ± 0.05	0.56 ± 0.02	0.39 ± 0.01	0.27 ± 0.03	0.13 ± 0.01	0.06 ± 0.01	0.06 ± 0.02	0.38 ± 0.03
Stomach	0.66 ± 0.02	0.59 ± 0.02	0.57 ± 0.02	0.58 ± 0.06	0.41 ± 0.09	0.28 ± 0.04	0.10 ± 0.01	0.75 ± 0.03
Stomach^3-c	0.01 ± 0.001	0.09 ± 0.03	0.20 ± 0.03	0.73 ± 0.05	0.66 ± 0.34	0.47 ± 0.25	0.43 ± 0.13	1.41 ± 0.11
Small intestine	3.34 ± 0.16	3.35 ± 0.08	4.98 ± 0.15	5.26 ± 0.49	3.26 ± 0.32	0.86 ± 0.12	0.24 ± 0.02	3.50 ± 0.11
Small intestine^3-c	2.39 ± 0.17	6.14 ± 0.24	11.85 ± 0.33	8.98 ± 0.35	5.35 ± 0.53	0.69 ± 0.27	0.16 ± 0.03	3.80 ± 0.23
Colon	1.08 ± 0.03	1.32 ± 0.03	1.38 ± 0.03	1.21 ± 0.07	0.57 ± 0.02	0.27 ± 0.02	0.14 ± 0.01	1.39 ± 0.07
Colon^3-c	2.02 ± 0.07	3.33 ± 0.09	3.93 ± 0.20	2.31 ± 0.29	0.91 ± 0.06	1.08 ± 0.36	0.30 ± 0.04	3.25 ± 0.18
Urine_{(total [_¹⁴} _C]MCA)	0.74 ± 0.46	2.19 ± 0.28	5.92 ± 0.39	11.37 ± 1.27	27.65 ± 3.52	57.30 ± 1.13	58.62 ± 4.24	N.D.
Urine_{(parent MCA)}	B.D.	1.81 ± 0.21	2.91 ± 0.38	8.18 ± 1.30	17.96 ± 1.84	39.72 ± 0.85	39.85 ± 4.89	N.D.
Feces	—^3-d	0.26 ± 0.06	0.61 ± 0.16	1.53 ± 0.44	1.76 ± 0.68	1.21 ± 0.33	0.86 ± 0.21	N.D.

N.D., not determined; B.D., below detection limit.
↵3-a Collected from dead rats (all rats died between 50 and 70 min after dosing). Radioactivity was determined in the whole blood of dead rats.
↵3-b Mean ± standard error (n = 5 from 5–45 min, n = at least 3 from 2–16 h due to mortality, n = 7 for dead rats).
↵3-c Contents.
↵3-d —, no feces excreted.