Subchronic application of humic acids and associated compounds provokes histological changes of goitre in the rat.
1. Different preparations of humic acids, a pyrogallol oxydation product (PYROP) and resorcinol were administered to male and female rats with the drinking water for 8 to 14 weeks. 2. By histometrical evaluation of the thyroid glands, an increase of the mean epithelial cell height of follicular epithelial cells was established in the 0.1% humic acid groups, 0.1% PYROP group and the 0.004% resorcinol groups. Females seemed to be more sensitive than males. Additionally, in some experiments, a decrease of the mean follicular diameter was found, which was the result of newly formed little follicles. The changes must be considered as a precursor of goitre. 3. In one of the experiments, in which circulating thyroid hormones were investigated, the serum thyroxine level in the male 0.1% humic acid group and the free thyroxine index in the female 0.1% humic group were diminished as compared to the control groups.
Seffner
W
W
Institute for Water-, Soil- and Air-Hygiene, Bad Elster Branch, Germany.
Schiller
F
F
Heinze
R
R
Breng
R
R
D000818:Animals; D005260:Female; D006042:Goiter / Q000097:blood / Q000139:chemically induced* / Q000473:pathology; D006812:Humic Substances / Q000633:toxicity*; D008297:Male; D011748:Pyrogallol / Q000031:analogs & derivatives / Q000633:toxicity; D051381:Rats; D012118:Resorcinols / Q000633:toxicity; D013974:Thyroxine / Q000097:blood
D006812:Humic Substances; D012118:Resorcinols; D011748:Pyrogallol; D013974:Thyroxine; C031389:resorcinol