Asymmetric distribution of alkaline phosphatase activity in the hair and wool follicles of sheep.

The strongest reaction for AP in both active and quiescent follicles was seen in the dermal papillae (Figs. 1 and 2), occasionally in the upper part only. The presence of AP in this region (Table 1), particularly during the active phase of hair growth, has now been reported in many species, suggesting that it plays an important role in hair growth. The blood vessels within the dermal papillae of active follicles, which range from single capillary loops (Fig. 3) to complex networks, were also reactive for this enzyme. AP in the matrix region of the bulb was usually demonstrated on only one side of the bulb (Figs. 1—3). Although this asymmetric distribution of AP was present in follicles from various body regions (Table I), it occurred mcst frequently in samples from the flank. In contrast, neither of the adjacent sites (the flauk-inguen junction and the inguen)