The Biphasic Regulatory Effect of Diphencyprone on Mouse Hair Growth and Its Relation to Protein Kinase C Isoforms

In the study conducted by Li, Fiedler, and Kumar, BALB/c mice were used to investigate the effects of diphencyprone (DPCP) on hair growth and its relationship with protein kinase C (PKC) isoforms. The mice were sensitized with 2% DPCP and then rechallenged weekly with 0.1% DPCP for 4 weeks, with the opposite side treated with acetone as a control. Initially, enhanced hair growth was observed on the treated side, which continued for 2 weeks. However, after the third elicitation, hair growth slowed down for nearly 2 weeks. Western immunoblots showed that PKC isoforms α, β, and δ were down-regulated on the treated side during the induction phase and first elicitation but were higher prior to the hair growth inhibition. The results suggest that the down-regulation and subsequent over-expression of PKC isoforms α, β, and δ may be associated with the induction and retardation of hair growth, respectively.