[Differentiation of foetal and prepuberty leydig cell in electron microscope (author's transl)]

A morphometric study of intra-uterine and extra-uterine Leydig cell differentiation was carried out by the Weibel's technique which was adapted for morphometry on electronmicrography. The results obtained in rats, the animals studied in this investigation, were: a) Testis of intra-uterine life as well as those of extra-uterine life displayed Leydig cells with lipid droplets. b) The percentage of Leydig cells varied from one testis to another. c) This percentage increased at 20th day of intra-uterine life and between 60th and 90th day of extra-uterine life. d) The percentage of lipid droplets within cytoplasm of Leydig cell increased at 20th day of intra-uterine life, at 15th day of extra-uterine life and at the proximity of puberty. e) The percentages of mitochondria are at inverse ratio of percentage of lipid droplets until the 40th day of life.