The Fate of the Male Germ Cell

THE FASCINATION The male germ cell is the only cell of the human organism that leaves the body when it has achieved its final, highly sophisticated structure and properties. The male germ cell is designed for one purpose only: to reach the female gametes and to fertilize them. The various stages in the development of the male germ cell are characterized by proliferative phases, by the recombination of the maternal and paternal chromosomes, and by the differentiation and development of a specialized transport vehicle, the spermato zoon. Furthermore, the establishment of a special pool of stem cells, the spermatogonia, guarantees the continuity of the sperm-generation process from puberty to old age. THE FATE OF THE MALE GERM CELL The destiny of any individual germ cell is determined by a program that we know only in fragments. On the one hand every human male is able to produce many billions of germ cells in his lifetime, yet the chance of any single sperm reaching and fertilizing the female germ cell is exceedingly rare. A fertility disturbance means that somewhere during the complicated playing out of the germ cell program mistakes are made, and the program fails. It is still a fact that more than 50% of men presenting with male factor infertility have to be diagnosed as idiopathic, largely because of our lack of knowledge and conse quent lack of appropriate diagnostic tools.

Zusammenfassung
Proceedings of a symposium held in Hamburg, Germany, December 5-7, 1996

Inhalt

1. Human Reproduction: The Missing Parts of the Puzzle.- Section A: Genes, Chromosomes, and Fertility.- 2. Human Y Chromosome Deletions in Yg11 and Male Fertility.- 3. Frequency of Y-Chromosome Microdeletions (Yq11.2223) in Men with Reduced Sperm Quality Requesting Assisted Reproduction.- 4. Histone Gene Expression and Chromatin Structure during Spermatogenesis.- 5. Histone Gene Expression in the Human Testis.- Section B: Germ Cell Differentiation and Tumorigenesis.- 6. Endocrine Control of Germ Cell Proliferation in the Primate Testis: What Do We Really Know?.- 7. Quantification of Somatic and Spermatogenic Cell Proliferation in Testes of Ruminants.- 8. The Immortalized Mouse Germ Cell Lines GC-1spg and GC-2spd as a Model for Mitochondrial Differentiation during Meiosis.- 9. A Novel Endozepine-like Peptide (ELP) Is Exclusively Expressed in Male Germ Cells.- 10. Investigation on the Proliferation of Spermatogonia in Normal and Pathologic Human Seminiferous Epithelium.- 11. Rapid Method to Detect CIS-Cells.- 12. Testicular Tumor Cells Pass through the Epididymal Ducts.- 13. AgNOR in Human Leydig Cell Tumors.- 14. Endocrinological Disturbances in Germ Cell Tumour Patients: Comparison of Hormone Levels and Kinetics in Peripheral and Testicular Vein Blood.- 15. Reinvestigation of Patients after Primary Therapy of Testicular Tumor.- 16. Carcinoma-in-Situ in Testes with Germ Cell Tumour: Comparison of Clinical Parameters with Histological Findings in Testicular Tissue Near to and Distant from the Tumour.- 17. Intratesticular Sperm Extraction: Basis for Successful Treatment of Infertility in Men with Ejaculatory Azoospermia.- Section C: The Role of the Testicular Accessory Cells.- 18. Molecular Pathophysiology of the Pituitary-Gonadal Axis.- 19. Fetal and PerinatalInfluence of Xenoestrogens on Testis Gene Expression.- 20. Protease-Protease Inhibitor Interactions in Sertoli Cell-Germ Cell Crosstalk.- 21. New Aspects of Leydig Cell Function.- 22. Sertoli Cell-Specific Gene Expression in Conditionally Immortalized Cell Lines.- 23. Functional Markers for Fetal and Postnatal Differentiation of Rat Leydig Cells.- 24. Enzyme Histochemical Addition to Morphological Features of Leydig Cells in Senium.- 25. Differential Display PCR Cloning of W/WV-Mutant Testis Specific Genes.- 26. Immunoreactivity for Glial Cell Markers in the Human Testis.- 27. Insulin-like Growth Factor-Binding Protein (IGFBP)-5 in Human Testicular Tubules.- 28. A Novel Role for Atrial Natriuretic Peptide (ANP) in Testis.- 29. Nerve Growth Factor (NGF) Receptors in Male Reproductive Organs.- 30. Delayed Onset of Spermatid Elongation in the Pubertal Golden Hamster Testis Depends on a Developmental Deficiency of Leydig Cell-11ß-HSD.- Section D: Compartmentalization, Vascularization, and Angiogenesis.- 31. Compartmentalization of the lntertubular Space in the Human Testis.- 32. Microcirculation and the Vascular Control of the Testis.- 33. Expression of VEGF and Its Receptors and Capillary Density in Leydig Cell Tumors of the Human Testis.- 34. Angioarchitecture of the Human Spermatic Cord.- 35. Morphological and Functional Aspects of the Human Spermatic Cord Veins.- 36. Semen Analysis after Treatment of Varicocele by Antegrade Scrotal Sclerotherapy.- 37. VEGF Modulates the Capillaries of the Human Epididymis.- 38. Endothelin-1 and Its Receptors in the Human Epididymis.- Section E: Post-Testicular Sperm Maturation.- 39. The Role of Apocrine Released Proteins in the Post-Testicular Regulation of Human Sperm Function.- 40. The Molecular Biology of the Sperm Surface:Post-Testicular Membrane Remodelling.- 41. Purification and Structural Analysis of Sperm CD52, a GPI-Anchored Membrane Protein.- 42. Measurement of Calcium in Single Human Spermatozoa.- 43. Putative Role of a Serpin in Modulation of Acrosome Reaction.- 44. Immunoelectron Microscopic Studies on Outer Dense Fibres.- 45. The Use of Spin-Labelled Phospholipid Analogues to Characterize the Transverse Distribution of Phospholipids and the Activity of Phospholipad?-?2 in the Cell Membrane of Bull Spermatozoa.- Section F: Control of the Male and Female Tracts.- 46. Interactions between Leukocytes and the Male Reproductive System: The Unanswered Questions.- 47. Oxytocin and Male Reproductive Function.- 48. Sensory Innervation of the Human Penis.- 49. The Uterine Peristaltic Pump: Normal and Impeded Sperm Transport within the Female Genital Tract.- 50. Egg-Cumulus-Oviduct Interactions and Fertilization.- Section G: Gamete Interaction and Fertilization.- 51. The Cell Biology of Fertilization.- 52. The Role of Carbohydrates in Sperm-Egg Interaction.- 53. X-Ray Crystallographic Analysis of Boar PSP-I/PSP-II Complex: A Zona Pellucida-Binding Protein.- 54. The Zona Pellucida Receptors.