[Federal Register Volume 59, Number 178 (Thursday, September 15, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-22813]


[[Page Unknown]]

[Federal Register: September 15, 1994]


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DEPARTMENT OF HEALTH AND HUMAN SERVICES
 

National Toxicology Program; Availability of Technical Report on 
Toxicology and Carcinogenesis; Studies of Corn Oil, Safflower Oil, and 
Tricaprylin

    The HHS' National Toxicology Program announces the availability of 
the NTP Technical Report on the comparative toxicology studies of corn 
oil which has been used for years as a vehicle to administer 
unpalatable or volatile chemicals to rodents during hazard 
identification studies. The studies included the evaluation of 
safflower oil, and tricaprylin as well.
    Comparative toxicology studies were conducted by administering corn 
oil, safflower coil, and tricaprylin by gavage to male F344/N rats for 
2 years. Each vehicle was administered by gavage at volumes of 2.5, 5, 
or 10 mL/kg body weight once daily for 5 days per week. To evaluate the 
potential role of corn oil in promoting a pancreatic proliferative 
effect, 500 mg dichloromethane/kg body weight was administered in 2.5, 
5 or 10 mL corn oil/kg body weight for 2 years to male F344/N rats. 
Dichloromethane was chosen because the chemical appeared to cause 
pancreatic proliferative lesions when administered by gavage in a corn 
oil vehicle but not when the exposure was by inhalation. In each of 
these studies, the term ``dose'' refers to the volume of gavage vehicle 
administered.
    These studies were designed to evaluate the effects of various 
concentrations of an oil very high in polyunsaturated fat (safflower 
oil), an oil containing high levels of polyunsaturated and 
monounsaturated fats (corn oil), and an oil containing saturated 
medium-chain fatty acids (tricaprylin) on the incidence and pattern of 
neoplasms in the F344/N rat. In addition, safflower oil and tricaprylin 
were evaluated as replacements for the corn oil vehicle.
    These studies demonstrate that safflower oil and tricaprylin do not 
offer significant advantages over corn oil as a gavage vehicle in long-
term rodent studies. Corn oil, safflower oil, and tricaprylin each 
caused hyperplasia and adenoma of the exocrine pancreas, decreased 
incidences of mononuclear cell leukemia, and reduced incidences or 
severity of nephropathy in male F344/N rats. There was an increased 
incidence of squamous cell papillomas of the forestomach in F344/N rats 
receiving 10 mL tricaprylin/kg. Further, the use of corn oil as a 
gavage vehicle may have a confounding effect on the interpretation of 
chemical-induced proliferative lesions of the exocrine pancreas and 
mononuclear cell leukemia in male F344/N rats.
    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 Comparative Toxicology Studies of Corn Oil, Safflower 
Oil, and Tricaprylin (CAS Nos. 8001-30-7, 8001-23-8, and 538-23-8) in 
Male F344/N Rats as vehicle for Gavage (TR-426) are available without 
charge from Central Data Management, NIEHS, MD A0-01, P.O. Box 12233, 
Research Triangle Park, NC 27709; telephone (919) 541-3419.

    Dated: September 8, 1994.
Kenneth Olden,
Director, National Toxicology Program.
[FR Doc. 94-22813 Filed 9-14-94; 8:45 am]
BILLING CODE 4140-01-M