Changes in the matrix proteins of wool and mouse hair following the administration of depilatory compounds.
After sheep were defleeced with mimosine, cyclophosphamide or N-[5-(4-aminophenoxy)pentyl]-phthalimide, the first samples of the new growth of wool differed markedly in composition from the pretreatment samples, there being substantial reductions in the high-tyrosine proteins and increases in the high-sulfur proteins. Similar results were obtained with mice dehaired with mimosine and with sheep treated with low levels of mimosine which resulted in weakened wool rather than depilation. The composition of later samples of the regrowth wool showed progressive changes with time. The high-tyrosine proteins tended to approach the pretreatment levels, although this may take up to 12 weeks to occur, whereas the levels of high-sulfur proteins, after the initial increase, often fell below normal. In experiments involving defleecing with cyclophosphamide, the level of the latter proteins was still below normal after 3 months. The possibility that this altered protein composition of keratin fibres is characteristic of that portion of fibre first produced by a new or regenerating follicle was investigated in sheep and mice. It was found that wool follicles regenerating after plucking, and newly operating follicles in young sheep and mice, also produced wool and hair with a reduced content of high-tyrosine proteins. It is suggested, therefore, that the apparent long-term inhibition of the high-tyrosine proteins may not be the direct consequence of the administration of the chemical but rather be characteristic of normal wool and hair regrowth. Infusion of an amino acid mixture lacking methionine into the abomasum of sheep caused the growth of weak wool but did not suppress the synthesis of the high-tyrosine proteins. This is in contrast with previous findings that treatments which weaken wool also suppress high-tyrosine proteins.