Subchronic Toxicity of Cupric Sulfate Administered in Drinking Water and Feed to Rats and Mice

Subchronic Toxicity of Cupric Sulfate Administered in DrinkingWater and Feed to Rats and Mice. HÉBERT, C. D., ELWELL,M. R., TRAVLOS, G. S., FITZ, C. J., AND BUCHER, J. R. (1993).Fundam. Appl. Toxicol. 21, 461–475. The effects of acute poisoning by cupric sulfate in a numberof species are well known; however, the effects of chronic low-levelingestion of cupric sulfate are less well characterized. Becauseexposure of humans to cupric sulfate may occur through drinkingwater, food, soil, or ambient air, subchronic toxicity studieswere conducted in male and female F344/N rats and B6C3F₁ miceby the drinking water (2-week exposure) and dosed feed (2-and13-week exposure) routes. Animals were evaluated for histopathology,clinical pathology, reproductive toxicity, and tissue metalaccumulation, and target organs were examined by a variety ofspecial stains and by electron microscopy to characterize theobserved lesions. In drinking water, cupric sulfate concentrationsof 300 to 100 ppm produced no ill effects, whereas concentrationsof 3000 to 30,000 ppm were lethal to rats and mice within 2weeks. In feed, cupric sulfate concentrations of 4000 to 16,000ppm caused significant reductions in body weight gain in bothspecies in the 2- and 13-week studies. Hyperplasia and hyperkeratosisof the limiting ridge of the forestomach were present in bothspecies in the 2- and 13-week studies. Rats in the dosed feedstudies had a dose-related increase in inflammation in the liverand changes in clinical chemistry parameters which were indicativeof hepatocellular damage and cholestasis. Histologic changesin the kidneys of rats consisted of a dose-related increasein the number and size of eosinophilic protein droplets in theepithelial cytoplasm and the lumina of the proximal convolutedtubules. Droplets were larger and more numerous in males thanin females. Urinalysis results were suggestive of renal tubularepithelial damage. Iron staining of spleens from treated animalsindicated a marked depletion of iron stores in both male andfemale rats, but not in mice, while hematologic and clinicalchemistry alterations in rats in the 13-week study, along withhistologic changes in bone in the 2-week dosed feed study, wereindicative of a microcytic anemia. Cupric sulfate produced noadverse effects on any of the reproductive parameters measuredin rats or mice of either sex. These results indicate that cupricsulfate at high exposure levels is a hepatic and renal toxicant,as well as an inducer of anemia in rodents, with rats more sensitivethan mice following subchronic exposure.     

Inhalation Toxicity of 1,6-Hexanediamine Dihydrochloride in F344/N Rats and B6C3F1 Mice

1,6-Hexanediamine (HDA) is a high production volume chemicalwhich is used as an intermediate in the synthesis of paints,resins, inks, and textiles and as a corrosion inhibitor in lubricants.Two- and 13-week studies of the toxicity of the dihydrochloridesalt of HDA (HDDC) were conducted in male and female Fischer344/N rats and B6C3F₁ mice using whole-body inhalation exposure.Both species were evaluated for histopatho-logic and reproductiveeffects, and rats were examined for clinical chemistry and hematologicchanges. In the 2-week inhalation studies, animals were exposedto 10–800 mg HDDC/m³, 6 hr per day. All rats, all femalemice, and two of five male mice in the high-exposure group diedbefore the end of the study. Surviving mice in this group hada dose-dependent depression in body weight gain. Clinical signswere primarily related to upper respiratory tract irritationand included dyspnea and nasal discharge in both species. Treatment-relatedhistopathologic lesions included inflammation and necrosis ofthe laryngeal epithelium of both species and the tracheal epitheliumof mice, as well as focal inflammation and ulceration of therespiratory and olfactory nasal mucosa. In the 13-week inhalationstudies, animals were exposed to HDDC at concentrations of 1.6–160mg/ m³ for 6 hr per day, 5 days per week. In addition to thebase study groups, a supplemental group of rats at each exposurelevel was included to assess the effect of HDDC on reproduction.No treatment-related changes in organ weights or organ-to-body-weightratios occurred in rats, and no treatment-related clinical signsor gross lesions were seen in either species. Chemical-relatedmicroscopic lesions were limited to the upper respiratory tract(larynx and nasal passages) in the two highest exposure groupsand were similar in both species. These lesions included minimalto mild focal erosion, ulceration, inflammation, and hyperplasiaof the laryngeal epithelium, in addition to degeneration ofthe olfactory and respiratory nasal epithelium. HDDC causedno significant changes in sperm morphology or vaginal cytologyand no significant adverse effects on reproduction in rats ormice. Hematologic and clinical chemistry changes in rats wereminor and sporadic and were not accompanied by related histologicfindings. HDDC did not increase the frequency of micronucleatederythrocytes in mice. In summary, the toxicity of HDDC to ratsand mice was a result of the irritant properties of the chemical,was limited primarily to the nasal passages and upper airways,and was consistent with the effects of other irritant chemicalsadministered by inhalation.     

Toxicity and Carcinogenicity of {Delta}9-Tetrahydrocannabinol in Fischer Rats and B6C3F1 Mice

⁹-Tetrahydrocannabinol (⁹-THC) was studied for potential carcinogenicityin rodents because it is the principal psychoactive ingredientin marihuana and it has potential medicinal uses. ⁹-THC in cornoil was administered by gavage to groups of male and femaleFischer rats and B6C3F1 mice at 0, 5, 15, 50, 150, or 500 mg/kg,5 days a week for 13 weeks and for 13-week plus a 9-week recoveryperiod, and to groups of rats at 0, 12.5, 25, or 50 mg/kg andmice at 0, 125, 250, or 500 mg/kg, 5 times a week for 2 years.In all studies, mean body weights of dosed male and female ratsand mice were lower than controls but feed consumptions weresimilar. Convulsions and hyperactivity were observed in dosedrats and mice; the onset and frequency were dose related. SerumFSH and LH levels hi all dosed male rats and corticosteronelevels in 25 mg/kg female rats were significantly higher thancontrols at 15 months in the 2-year studies. ⁹-THC administrationfor 13 weeks induced testicular atrophy and uterine and ovarianhypoplasia; the lesions persisted in a 9-week recovery period.In the 2-year studies, survival of dosed rats was higher thancontrols; that of mice was similar to controls. Incidences oftesticular interstitial cell, pancreas and pituitary gland adenomasin male rats, mammary gland fibroadenoma and uterus stromalpolyp in female rats, and hepatocellular adenoma/carcinoma inmale and female mice were reduced in a dose-related manner.Decreased tumor incidences may be at least in part due to reducedbody weights of dosed animals. Incidences of thyroid gland follicularcell hyperplasia were increased in all dosed groups of maleand female mice, and follicular cell adenomas were significantlyincreased in the 125 mg/kg group of males, but there was noevidence of a dose-related trend in proliferative lesions ofthe thyroid. There was no evidence that ⁹-THC was carcinogenicin rats or mice.