V.—Investigations into the Distribution of Thiol Groups in the Skin Follicles of Mice and Sheep and the Entry of Labelled Sulphur Compounds

Abstract

SynopsisThe distribution of thiol (sulphydryl) groups in the wool follicle has been studied with Bennett's reagent; the strongest reaction was found immediately proximal to the prekeratinization (keratogenous) region. Mice and lambs were injected with cystine labelled with sulphur-35 and radioactivity was detected in the follicles, autoradiographically within a few minutes. A peak of activity formed in the follicle during the first few hours after injection which suggested that there is a rapid turnover of cystine in the body. But a small amount of activity could still be detected in the follicle up to at least 3 weeks afterwards.Sulphur seems to enter the follicle immediately above the bulb, and reaches the fibre first on the side at which it is keratinized last. This method indicated the relative proportion of sulphur in different regions of the follicle and suggested that the sulphur becomes concentrated on keratinization. No difference in sulphur content was found between primary and secondary follicles, the ortho- and paracortex, and apparently between cortex and medulla. When labelled sulphate was injected, activity appeared first in the outer sheath, and only later in the fibre.