Factors Which Affect the Fiber Output of Isolated Wool Follicles Maintained In Vitro

The study developed an in vitro technique to grow individual wool follicles, revealing that wool growth was regulated by endocrine growth factors rather than the follicles themselves. Wool fibres produced in vitro were similar to those grown on sheep, but at half the growth rate. Seasonal and nutritional influences on wool growth observed in vivo were absent in vitro, suggesting extrafollicular regulation. Ovine serum, particularly from winter, inhibited fibre growth, with English Leicester sheep follicles more sensitive than Drysdale sheep. Key inhibitory components were identified in the serum. Growth factors like basic fibroblast growth factor and minoxidil reduced fibre growth, while insulin and others had no effect. The findings supported the hypothesis that wool growth is systemically regulated by endocrine factors.