ABSTRACT
Strips of skin from the flank were exchanged between rats aged 28 and 49 days respectively, so that their expected hair growth waves would be out of phase. Similarly sited autografts were used as controls.
In the wave of growth immediately following grafting eruption of hairs on the homografts coincided with that on the donor’s autograft. In the older recipient this was significantly in advance and in the younger recipient significantly in retard of hair growth on their autografts. Thus, follicular activity has an inherent rhythm which continues for at least one cycle after homotopic grafting.
In the succeeding waves of growth, when follicular activity in the recipient preceded that in the donor, the time of eruption of hair on the homograft was advanced, and by the third wave after grafting was completely in line with its host. When follicular activity in the recipient succeeded that in the donor the homografts tended to behave donor-wise.
These results show clearly that both an inherent rhythm and a systemic stimulus are involved in follicular activity at a particular site.
