title: Mitosis in the oesophageal epithelium of rats during chronic antithyroid treatment with carbimazole.
abstract: The mitotic activity of the oesophageal epithelium of male rats maintained under carefully controlled conditions was studied, using the metaphase-arrest agent, vincristine sulphate. The accumulation of metaphases was linear (r = 0.97). In untreated rats there was a clear mitotic rhythm with a peak metaphase index (expressed as a percentage) of 12.4 +/- 0.86 (S.E.M.) at 12.00-15.00 h and a trough of 1.3 +/- 0.35 at 24.00 h. The overall mean metaphase index was 5.4 +/- 0.76. The effect of treatment with the antithyroid agent, carbimazole (0.1 g/100 ml in the drinking water), for 3 weeks was to depress the higher values at 12.00-18.00 h (P less than 0.01), while leaving the overall index unchanged. Carbimazole caused a significant (P less than 0.01), transient 40% increase in the metaphase index after 2 days; thereafter the metaphase index remained at control levels until 12 weeks of treatment when a steady decline occurred until 24 weeks. The results are in contrast to those in previously described experiments on thyroid follicular cells which show a large increase in the first few days of treatment, followed by a steady decline towards control levels at 12 weeks. The metabolic activity of the animals is about 50% of normal at 12 weeks when both the oesophageal epithelium and the thyroid follicular cells begin to show a reduction in proliferative activity.
authors: Department of Physiology, Trinity College, Dublin, Ireland.
authors: A R
authors: AR
authors: Tuffery
authors: M
authors: M
authors: Mobarak
mesh_terms: D000818:Animals; D002231:Carbimazole / Q000494:pharmacology*; D004847:Epithelial Cells; D004848:Epithelium / Q000502:physiology; D004947:Esophagus / Q000166:cytology / Q000502:physiology*; D008297:Male; D008677:Metaphase; D008938:Mitosis / Q000187:drug effects*; D051381:Rats; D011919:Rats, Inbred Strains; D013961:Thyroid Gland / Q000187:drug effects*
chemical_list: D002231:Carbimazole