The Effect of a Single Epilation on Successive Hair Eruptions in Normal and Hormone-Treated Rats

The study investigated the effects of hair plucking on hair growth cycles in normal and hormone-treated female rats. It was found that epilation generally advanced the next hair eruption unless performed just before a spontaneous eruption. The interval to new hair growth varied depending on whether hairs were plucked from resting or growing follicles, with hormonal treatments like estradiol or propylthiouracil extending the cycle and spaying or thyroxine shortening it. Epilation consistently advanced subsequent hair eruptions, with the second eruption being more advanced than the first. While the first post-epilation growth phase remained unchanged, the resting phase was shortened, and later cycles were prolonged. There was some evidence of a systemic control mechanism attempting to synchronize the cycles of epilated and non-epilated follicles, though complete synchrony was not achieved within a few cycles.