Detection of triethylenemelamine-induced translocation heterozygotes in CD-1 mice: fertility and cytological methods.

A study was conducted to determine the extent to which translocation carriers can be missed in the heritable translocation test. CD-1 male mice were treated with the mutagen triethylenemelamine and bred to untreated females and male progeny were subjected to fertility and cytogenetic analyses. Fertility testing involved mating 1 male to 3 virgin females and subjecting the females to uterine analysis. The males were classified as having normal or reduced fertility according to the number of live implants produced by the females. The cytogenetic analysis involved scoring 25 primary spermatocytes per mouse for translocation multivalents. A total of 103 male progeny were analyzed. Evaluation of fertility and cytogenetic data confirmed the presence of 18 translocation heterozygotes among the male progeny. On the basis of fertility testing, 1 translocation heterozygote was classified as normal (false negative) based on the production of 11 or more live implants by at least 1 mated female. On the basis of cytogenetic analysis of 25 cells per mouse, 1 partially sterile male was classified as normal (false negative); however, analysis of additional cells showed that this mouse was a translocation heterozygote. The study demonstrates the importance of evaluating fertility and cytogenetic criteria to minimize the extent of misclassification in conducting a heritable translocation test.

Absorption, distribution, and excretion of [14C]patulin by rats.

Adult rats of both sexes were given a single oral dose of [14C] patulin and were sacrificed at various time intervals from 4 hr to 7 days following administration of the mycotoxin. Two groups of rats were employed; the treated group had been exposed to daily oral doses of unlabeled patulin (dissolved in pH 5.0 citrate buffer) in utero and for 41-66 wk after weaning, while the controls were given the buffer only throughout gestation and for 38-81 wk after weaning. Approximately 49% of the administered 14C radioactivity was recovered from feces and 36% from urine within 7 days after dosing. Most of the excretion of labeled material occurred within the first 24 hr. All of the 14C activity detected in the urine samples was either metabolites and/or conjugates of the original [14C]patulin. About 1-2% of the total radioactivity was recovered as 14CO2 from expired air. Carbon-14 radioactivity in various tissues and organs was determined throughout the 7 day period; the most significant retention site was the red blood cells.

Intermediate-duration toxicity study of patulin in rats.

The toxicity of patulin was studied in two generations of Sprague-Dawley rats over a period of approximately 10 months. Patulin in 1 mM citrate buffer was administered by gavage to FO generation rats at a dose level of 0, 1.5, 7.5, or 15.0 mg/kg a body weight five times a week for 10-14 wk; females were treated seven times a week during pregnancy. High mortality and insufficient progeny in the groups given 7.5 and 15.0 mg/kg made it impossible to continue those two regimens into the second generation. The study was continued for 20-23 wk with F1A generation animals given 1.5 mg/kg and controls. The only lesion found at necropsy that could be attributed to patulin administration was gaseous distention of the gastrointestinal tract, which was probably the result of the antibiotic effect of this mycotoxin on the normal intestinal flora. A decreased weight gain in male rats of the FO generation was dose-related. An impairment in growth rates of F1A and F2A progeny of both sexes was statistically significant at the 1.5 mg/kg dose level. Fetuses taken from patulin-treated females on day 20 of pregnancy were noticeably smaller than controls fetuses and the difference was significant for F2A males. No other teratological abnormalities related to patulin dosing at the 1.5 mg/kg level were observed consistently in either F1A or F2A fetuses. Patulin did not appear to produce dominant lethal effects at dose levels up to 15.0 mg/kg when given by gavage to the males five times a week for 10 or 11 wk.

Acute, subacute, and residual effects of polychlorinated biphenyl (PCB) in rats. I. Biologic half-life in adipose tissue.

Sprague-Dawley rats were fed diets containing Aroclor 1254 at o, 5, 50, or 500 ppm for 4 wk. The biologic half-life of Aroclor 1254 in adipose tissue of rats fed 500 ppm, as determined by a gas chromatographic method, was 8 wk in males and 12 wk in females. These results are in line with sex-linked differences reported previously for other chlorinated hydrocarbons. It appears that the lower chlorine homologs in the Aroclor mixture are metabolized while those with higher chlorine content are lost more slowly.