Uptake of S³⁵-methionine in the epidermis of chick embryos and chicks

Summary

The author studied changes of S³⁵-methionine distribution in various functional regions of the epidermis of 17-day-old chick embryos and 8-day-old chicks. In both, during the first hours after injection, maximum uptake of S³⁵ occurred in the middle layers of the epidermis. Next the labelled cells gradually migrated into the stratum corneum. The rate rate of uptake of radioactive sulphur was not the same for all the regions, being higher the greater the rate of regeneration. In chicks the thickness of the stratum corneum of the epidermis regenerated per day was 8.5 μ, 3.7 μ, and 3.4 μ for the sole, head, and dorsum of the shank respectively; the differences were due to the different mitotic activities of these regions.