Long-term toxicity study of carmoisine in rats using animals exposed in utero.

Groups of 114 (control) or 66 (treated) rats of each sex were fed diets providing 0 (control), 100, 400 or 1200 mg carmoisine/kg body weight/day for 9 wk. Within each group the animals were mated monogamously. Treatment continued uninterrupted until the young were randomly selected (where possible one/sex/litter) from each of the litters to provide groups of 90 (control) and 54 (treated) rats of each sex. These received the same treatment as their parents for up to 110 wk for females or 115 wk for males. Apart from coloration of the fur, urine and faeces, treated rats did not differ in appearance or behaviour from the controls. Mortality was not affected by treatment. High-dose groups had reduced body-weight gain compared with that of the controls, despite slightly higher food intakes. Increased water intakes in the same animals accompanied a tendency to excrete larger volumes of urine. Haematological investigations at months 3, 6, 9, 12, 18 and 24, and on all survivors at the end of the study showed no treatment-related effects. Urine studies on 20 rats/sex/group at months 3, 6, 12, 18 and 24 showed no consistent treatment-related changes. Analyses of serum collected at the end of the study demonstrated low glucose concentrations in both sexes of the high-dose group and in intermediate-dose females. A few high-dose males had bladder hyperplasia while some high-dose females had increased incidences of adrenal blood/fibrin cysts or internal hyperplasia/medial hypertrophy of the pancreatic blood vessels. Tumours occurred with a similar distribution and incidence in all groups apart from an increased incidence of adrenal phaeochromocytoma in high-dose males. The incidence seen was well within the background incidence for this relatively common tumour in the same strain of rat under similar conditions. It is concluded that carmoisine is not carcinogenic and that the no-untoward-effect level in this study was 400 mg carmoisine/kg body weight/day.

Long-term toxicity study of Ponceau 4R in rats using animals exposed in utero.

Groups of 66 (treated) or 114 (control) rats of each sex were fed diets providing 0 (control), 50, 500 or 1250 mg Ponceau 4R/kg body weight/day for 60 days. The animals were then mated and allowed to rear their litters. At weaning, pups were selected for the long-term study to give treated groups of 54 (of each sex) and a control group of 96 (of each sex), with offspring always receiving the same treatment as their parents. Treatment continued until approximately 20% of animals survived, resulting in a duration of 114 wk for males and 118 wk for females. Body weight, food and water intake and clinical conditions were monitored regularly throughout the study. Blood and urine from 20 rats/sex/group from the high-dose and control groups were examined at months 3, 6, 12, 18 and 24. At the end of the study each animal was autopsied, selected organs were weighed, and a full range of tissues was preserved. High-dose animals showed a lower body-weight gain without any reduction in food intake. Water intake was higher than that of the controls in the medium- and high-dose groups and this was related to caecal enlargement and softening of faeces. No adverse changes were seen in the investigations of blood or urine apart from a higher incidence of females with higher levels of protein in urine at the 1250 mg/kg/day dose. No other findings of significance were seen and survival and tumour incidence were similar in all groups. A no-untoward-effect level was established at 500 mg Ponceau 4R/kg/day.

A three-generation reproduction study of Ponceau 4R in the rat.

Ponceau 4R was fed to three generations of rats, at dietary concentrations to provide 0, 50, 500 or 1250 mg/kg body weight/day. In each generation treated groups consisted of 36 rats of each sex while 60 females served as controls. Apart from the F0 generation, which started treatment as weanlings, treatment was continued throughout the study, providing in utero exposure of all offspring. The F0 generation was bred twice, on the first occasion to provide animals for the next generation and for a long-term study, and a second time to provide data on in utero and post-partum development. In each generation approximately one third of the females from each group were killed before parturition to provide data on in utero development. The foetuses from these animals were examined for skeletal abnormalities. Remaining animals were allowed to litter and the offspring were monitored for 21 days after birth for survival and development. All animals were killed and subjected to a post-mortem examination which, for a proportion of each group in each generation, included recording of organ weights. Although a few adult rats died during the study these deaths were not associated with treatment. Fur of the treated animals was coloured pink, and faeces and caecal contents of animals from the two highest dose groups were yellow, the faeces also being softer than those of the controls. Treatment had no observed effect on clinical observations, body weight or food and water intake at any stage of the study. Animals fed the two highest doses for prolonged periods had enlarged caeca, but this effect was not seen in weanling animals on the same treatment. Neither the caecal enlargement nor the liver weights seen in the F2 and F3 offspring were considered to be an adverse effect of treatment. No treatment-related effects were seen in the uterine contents of females at any generation, but the skeletons of treated foetuses showed a slightly more advanced development than those of the controls. Postnatal development of offspring was not affected by treatment at any stage of the study. Tissues from the F3 animals were examined by light microscopy and revealed no treatment-related effects. It is concluded that the no-adverse-effect level for Ponceau 4R is 1250 mg/kg body weight/day.