A Study of the Ultrastructural Localization of Hair Keratin Synthesis Utilizing Electron Microscopic Autoradiography in a Magnetic Field

Abstract

The sites of the incorporation of labeled cystine into keratinizing structures were studied in electron microscopic autoradiographs. The tracer used was cystine labeled with S 3~ emitting long-range ionizing particles. During exposure for 1 to 2 months, according to our method of electron microscopic autoradiography, emulsion-coated specimens were exposed to a static magnetic field which appeared to result in a marked increase in the number of reacted silver grains. In young Swiss mice receiving intraperitoneal injections at 1, 3, and 6 hours before biopsy, conventional autoradiography demonstrated that S 35-cystine was intensely localized in the keratogenous zone of anagen hair follicles, and that the radioactivity there increased in intensity progressively with time while the radioactivity in the hair bulb always remained very low. Our observations with electron microscopic autoradiography in a magnetic field appeared to indicate that at 3 and 6 hours after injection the S35-cystine was directly and specifically incorporated into tonofibrils in the hair cortex and into amorphous keratin granules of the hair cuticle layer, possibly without any particular concentration of this substance in the other cellular components. There seemed to be an appreciable concentration of cystine in tonofibrils of the cuticle of the inner root sheath. However, trichohyalin granules in the hair medulla and inner root sheath failed to show any evidence of cystine concentration. The improved sensitivity of the electron microscopic autoradiography with S35-cystine appeared to be partly due to the application of a static magnetic field. However, the reason for this could not be explained theoretically.

Sulfur-Containing Proteins and Epidermal Keratinization

“…In hair, large amounts of sulfur are known to be added to the fibers of cortical cells during cornification (4,10,15,16,21). This occurs primarily in the keratogenous zone and is readily demonstrated by electron microscopic radioautography (22).…”

Effects of static magnetic fields on eukaryotic cytoskeleton

“…维 蛋 白 可 能 会 在 特 定 磁 场 作 用 下 发 生 变 化 . 例 如 , 1964年, Nakai [64] 发现外加的稳态磁场(强度未知)可 以增强角蛋白(keratin)合成的电子显微镜放射自显 影, 但机制不清. 80 mT稳态磁场可以增强胰岛素样 生 长 因 子 1(IGF-1) 诱 导 的 肌 间 线 蛋 白 基 因 表 达 升 高 [65] .…”

Etude de l'action d'un traitement par voie topique sur la synthèse de la kératine pilaire chez le Rat

“…Afin d'etudier la formation des poils ou de la laine, I'incorporation de cysteine radioactive ainsi que d'autres acides amines marques comme la Leucine ou la Methionine a fait I'objet de multiples etudes (2, 3,4,5). De nombreux auteurs ont etudie par autoradiographie et microscopie Clectronique, aprks injection d'acides amines marques, la localisation de la radioactivite dans le bulbe pileux (2,6,7,8).…”