1;Acknowledgements;6 2;List of Contents;7 3;Chapter 1 Introduction;10 4;Chapter 2 History of and Recent Progress in Leydig Cell Research;12 4.1;2.1 More Than 150 Years Ago: The Discovery of Leydig Cells;12 4.2;2.2 100 Years Later: The Endocrine Characteristics of the Leydig Cells Were Revealed;14 4.3;2.3 Novel Aspects: Evidence for Neuroendocrine Properties of the Leydig Cells;15 4.4;2.4 Newer Results: Adult Leydig Cells Originate from Microvascular Mural Stem Cells (Pericytes and Vascular Smooth Muscle Cells);17 5;Chapter 3 Morphology of the Leydig Cells;18 5.1;3.1 Leydig Cells Represent a Heterogeneous Cell Population;18 6;Chapter 4 The Well-Known Endocrine Function of the Leydig Cells;28 7;Chapter 5 The Neuroendocrine Properties of the Leydig Cells;31 7.1;5.1 Considering Selected Substances;35 7.2;5.2 Hormones;44 7.3;5.3 Natriuretic Peptides;46 7.4;5.4 Neurofilament and Other Proteins;47 7.5;5.5 Astrocyte and Oligodendrocyte Marker Molecules;47 7.6;5.6 The Renin-Angiotensin System;48 7.7;5.7 VEGFs and Their Receptors;49 7.8;5.8 PDGFs and Their Receptors;50 8;Chapter 6 Development of the Testis;52 8.1;6.1 The Testis Arises from the Urogenital Ridge and the Indifferent Gonad Rudiment;52 8.2;6.2 Primordial Germ Cells Migrate from the Epiblast into the Genital Ridges;52 8.3;6.3 The Sertoli Cells Emerge from Migrating Cells of the Coelomic Epithelium and Contribute to the Formation of the Testicular Cords;53 8.4;6.4 Migrating Mesonephric Cells Contribute to the Generation of Other Somatic Cells in the Male Gonad;54 9;Chapter 7 Development of the Neuroendocrine Leydig Cells;56 9.1;7.1 Two Main Leydig Cell Types Differentiate During Testis Development: The Fetal-Type and the Adult-Type Leydig Cells;56 9.2;7.2 Origin and Differentiation of the Adult Neuroendocrine Leydig Cells;57 9.3;7.3 Definition and Classification of the Stem Cells;58 9.4;7.4 Postnatal Development of the Neuroendocrine Leydig Cells in Rat and Mouse Testis;60 9.5;7.5 EDS Treatment of Adult Rats Also Leads To Damage of the Seminiferous Epithelium;76 9.6;7.6 The Pericyte Is a Peculiar Cell Type Just Now Beginning To Be Understood;77 9.7;7.7 The Vascular Stem Cell Niche and the Stem-Cell-Like Progenitors of Testicular Leydig Cells;87 9.8;7.8 Leydig Cells May Be Continuously Generated from Stem/ Progenitors Cells in the Testes of Adult Mammals;89 9.9;7.9 Postnatal Development of Leydig Cells in Rodent Testis;91 9.10;7.10 Postnatal Development of Leydig Cells in the Human Testis;94 10;Chapter 8 Fetal and Adult Leydig Cells Are of Common Origin;95 10.1;8.1 Where Do the Leydig Cell Ancestors Come from?;96 10.2;8.2 The Development of the Fetal Leydig Cells Is Closely Associated with the Development of the Testis Vasculature;97 10.3;8.3 Leydig Cells, Blood Vessels and the Developing Testis;98 10.4;8.4 Are Stem Cells Really a Very Rare Population?;101 10.5;8.5 Leydig Stem/Progenitor Cells and the Neural Crest;104 10.6;8.6 The Aorta-Gonad-Mesonephros Region Harbours Many Diverse Stem Cells;108 11;Chapter 9 Concluding Remarks;110 12;References;113 13;Subject Index;154