API PUBL 32-31300-1985 MUTAGENICITY EVALUATION STUDIES IN THE RAT BONE MARROW CYTOGENETIC ASSAY IN THE MOUSE LYMPHOMA FORWARD MUTATION ASSAY LIGHT CATALYTIC CRACKED NAPTHA API Sample 81-03
Abstract Chromosome aberrations were determined in the bone marrow cells of Sprague-Dawley rats subchronically exposed by inhalation to API 81-03 (five daily doses). Three dose levels were employed: 2046@ 297 and 63 ppm. Bone marrow was sampled six hours after the last dose. Ten male and ten female animals were exposed to each dose and negative control level. The structural aberration frequency in bone marrow cells of rats exposed to API #81-03 did not differ significantly from the negative control at any tested dose. The percentages of cells showing one or more structural aberrations or two or more structural aberrations were likewise similar to the negative controls@ as was the frequency of numerical aberrations. These results were the same whether males or females or both sexes pooled were evaluated by the Student t-test@ A concurrent positive control substance@ triethylenemelamine@ showed significant increases in structural aberration frequency at two dose levels@ For in vitro treatments of the mouse lymphoma cell line@ L5178Y@ the mutant frequency at the thymidine kinase (TK) locus was not significantly increased. The cells were exposed to API #81-03 both in the presence and absence of rat liver S9 metabolic activation. API #81-03 was assayed at an applied concentration range of 7.81 nl/ml to 125 nl/ml without activation and from 7.81 nl/ml to 300 nl/ml in the presence of rat liver activation. A wide range of toxicities was Induced without inducing significant Increases In the mutant frequency. API #81-03 was therefore evaluated as inactive in the mouse lymphoma cell system.
API PUBL 32-31300-1985 history
1985API PUBL 32-31300-1985 MUTAGENICITY EVALUATION STUDIES IN THE RAT BONE MARROW CYTOGENETIC ASSAY IN THE MOUSE LYMPHOMA FORWARD MUTATION ASSAY LIGHT CATALYTIC CRACKED NAPTHA API Sample 81-03