[Federal Register Volume 59, Number 10 (Friday, January 14, 1994)]
[Unknown Section]
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From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-911]
[[Page Unknown]]
[Federal Register: January 14, 1994]
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DEPARTMENT OF HEALTH AND HUMAN SERVICES
National Toxicology Program; Availability of Technical Report on
Toxicology and Carcinogenesis Studies of o-Nitroanisole
The HHS' National Toxicology Program announces the availability of
the NTP Technical Report on the toxicology and carcinogenesis studies
of o-nitroanisole which is used as an intermediate for the preparation
of o-anisidine and in the manufacture of azo dyes.
Toxicology and carcinogenicity studies were conducted by feeding
groups of 60 F344 rats of each sex diets containing 0, 222, 666, or
2,000 ppm o-nitroanisole and groups of 60 B6C3F1 mice of each sex diets
containing 0, 666, 2,000, or 6,000 ppm o-nitroanisole for 103 weeks. In
a companion study, male and female rats were fed 0, 6,000, or 18,000
ppm o-nitroanisole for 6 months and maintained on untreated feed for
1\1/2\ years.
Under the conditions of these feed studies there was clear evidence
of carcinogenic activity\1\ of o-nitroanisole in male and female F344
rats that received diets containing 6,000 to 18,000 ppm for 6 months
based on overall increased incidences of benign and malignant neoplasms
of the urinary bladder, transitional cell neoplasms of the kidney, and
benign and malignant neoplasms of the large intestine. There was a
chemical-related increased incidence of mononuclear cell leukemia in
male and female rats receiving diets containing 222, 666, or 2,000 ppm
o-nitroanisole for 2 years. Marginally increased incidences of uncommon
renal tubule neoplasms in male rats and forestomach neoplasms in male
and female rats were considered uncertain findings. There was clear
evidence of carcinogenic activity of o-nitroanisole in male B6C3F1 mice
based on increased incidences of benign and malignant hepatocellular
neoplasms. There was some evidence of carcinogenic activity of o-
nitroanisole in female B6C3F1 mice based on increased incidences of
hepatocellular adenomas.
Increased severity of nephropathy in male rats, and increased
incidences of focal hyperplasia of the renal tubule epithelium and
forestomach ulcers in male rats, and of transitional cell hyperplasia
of the urinary bladder, focal hyperplasia of the forestomach, and
hyperplasia of transitional epithelium of the kidney pelvis in male and
female rats were associated with exposure to o-nitroanisole.
Questions or comments about the Technical Report should be directed
to Central Data Management at P.O. Box 12233, Research Triangle Park,
NC 27709 or telephone (919) 541-3419.
Copies of Toxicology and Carcinogenesis Studies of o-Nitroanisole
(CAS No. 91-23-6) in F344 Rats and B6C3F1 Mice (Feed Studies) (TR-416)
are available without charge from Central Data Management, NIEHS, MD
AO-01, P.O. Box 12233, Research Triangle Park, NC 27709; telephone
(919) 541-3419.
Dated: January 7, 1994.
Kenneth Olden,
Director, National Toxicology Program.
[FR Doc. 94-911 Filed 1-13-94; 8:45 am]
BILLING CODE 4140-01-M
