Some effects of a thallium salt on the proliferation of hair follicle cells.

Thallium sulphate has been given to young rats at 4 and 7 days of age and the mitotic activity of the hair follicles has been assessed quantitatively. It has been found that there is a marked decline in mitotic rate over 48 hr in the thallium-treated animals, which is followed by variable amounts of cell death in the matrix zone. No specific mitotic lesion was found or change in cell cycle indices. A failure of energy metabolism is suggested as a possible cause of the inhibition of hair follicle mitosis by thallium.