Slominski A, Paus R, Plonka P, Chakraborty A, Maurer M, Pruski D, Lukiewicz S
Department of Pathology and Laboratory Medicine, Albany Medical College, New York 12208.
J Invest Dermatol. 1994 Jun;102(6):862-9. doi: 10.1111/1523-1747.ep12382606.
Melanin synthesis of follicular melanocytes is strictly coupled to the growth stage of the hair cycle (anagen), ceases during follicle regression (catagen), and is absent throughout the resting stage (telogen). Having previously characterized the expression and activity of melanogenesis-related proteins during the telogen-anagen transition of the murine hair cycle (JID 96:172, 1991), we here report a biophysical and biochemical analysis of follicular melanogenesis during the anagen-catagen-telogen transformation of the C57 BL-6 mouse hair cycle. Tyrosinase activity and concentration as well as dopachrome tautomerase activity were compared with melanin synthesis, as measured by electron paramagnetic resonance spectroscopy (EPR). The visible changes in skin color and the histologically appreciable switch-off of melanin formation during the anagen-catagen transformation were accompanied by a steep decline in 1) the melanin-associated EPR signal of full-thickness mouse skin, 2) tyrosinase and dopachrome tautomerase activities, and 3) the skin concentration of 80-85-kD melanogenesis related protein and 66-68-kD tyrosinase protein. Telogen skin displayed a minimum of the EPR amplitude as well as of tyrosinase and dopachrome tautomerase activity detected. By EPR, only eumelanin was identified during all hair cycle stages. The gradual switch-off of melanogenesis during anagen VI started with an unexpectedly early decline of the EPR melanin signal, followed by dopachrome tautomerase activity and the concentration of 80-85-kD melanogenesis related protein. The initiation of catagen was characterized by a significant and rapid decrease in activity and concentration of tyrosinase, and was accompanied by a second drop in dopachrome tautomerase activity. Together, these biochemical and biophysical parameters of follicular melanogenesis serve as novel and differential markers for the imminent termination of anagen and the development of catagen. They also show that the switch-off of melanogenesis during the anagen-catagen-telogen transition is a stochastic process commencing already in mid anagen VI.
毛囊黑素细胞的黑色素合成与毛发周期（生长期）的生长阶段紧密相关，在毛囊退化（退行期）时停止，在整个休止期（静止期）均不存在。我们之前已对小鼠毛发周期从静止期到生长期转变过程中黑素生成相关蛋白的表达和活性进行了表征（《皮肤病学研究杂志》96:172, 1991），在此报告对C57 BL - 6小鼠毛发周期从生长期到退行期再到静止期转变过程中毛囊黑素生成的生物物理和生化分析。通过电子顺磁共振光谱（EPR）测量，将酪氨酸酶活性和浓度以及多巴色素互变异构酶活性与黑色素合成进行了比较。在生长期到退行期转变过程中，皮肤颜色的可见变化以及组织学上可观察到的黑色素形成停止，伴随着以下各项的急剧下降：1）全层小鼠皮肤中与黑色素相关的EPR信号；2）酪氨酸酶和多巴色素互变异构酶活性；3）80 - 85-kD黑素生成相关蛋白和66 - 68-kD酪氨酸酶蛋白的皮肤浓度。静止期皮肤的EPR振幅以及检测到的酪氨酸酶和多巴色素互变异构酶活性最低。通过EPR，在所有毛发周期阶段仅鉴定出真黑素。在生长期VI期间，黑色素生成的逐渐停止始于EPR黑色素信号意外提前下降，随后是多巴色素互变异构酶活性以及80 - 85-kD黑素生成相关蛋白浓度下降。退行期的开始以酪氨酸酶活性和浓度的显著快速下降为特征，并伴随着多巴色素互变异构酶活性的第二次下降。总之，这些毛囊黑素生成的生化和生物物理参数可作为生长期即将结束和退行期发展的新型差异标志物。它们还表明，在生长期到退行期再到静止期转变过程中黑色素生成的停止是一个早在生长期VI中期就已开始的随机过程。
