The Cycle of the Seminiferous Epithelium in Humans: A Need to Revisit?
- 10 September 2008
- journal article
- review article
- Published by Wiley in Journal of Andrology
- Vol. 29 (5), 469-487
- https://doi.org/10.2164/jandrol.107.004655
Abstract
Understanding the dynamics of spermatogenesis is central to clinical andrology or to probing environmental effects on human testes. This review considers what is known about renewal and proliferation of spermatogonia, how germ cells are organized in cellular associations constituting the cycle of the seminiferous epithelium, relative frequencies of cellular associations, durations of the cycle of the seminiferous epithelium and spermatogenesis, and measurement of daily sperm production. Daily sperm production (DSP) per testis tends to decline with advancing age. Regardless of age, there is substantial loss of potential sperm from degeneration of spermatocytes, but not spermatids. DSP per gram testis parenchyma or DSP per testis cannot be predicted on the basis of testis size or age of a man. The review shows why our 1960s data base is neither robust nor precise and suggests how deficiencies might be rectified. New cellular associations should be defined, with none representing >15% of the cycle of the seminiferous epithelium. Then determine when A(pale)-spermatogonia become committed to proliferate or how many mitotic divisions occur thereafter. Restudy the duration of spermatogenesis because the accepted value might be in error by approximately 6 days. Restudying human spermatogenesis will benefit clinicians, toxicologists, and epidemiologists probing testis function by direct evaluations or indirectly via evaluations of quantity and quality of sperm ejaculated. It also will benefit scientists interested in renewal and proliferation of spermatogonia, or a spermatogonium as a prototype stem cell.Keywords
This publication has 73 references indexed in Scilit:
- Impact of environmental pollutants on the male: Effects on germ cell differentiationAnimal Reproduction Science, 2008
- A chemical method for fast and sensitive detection of DNA synthesis in vivoProceedings of the National Academy of Sciences of the United States of America, 2008
- Chronic Exposure to Low Levels of Dibromoacetic Acid, a Water Disinfection By‐product, Adversely Affects Reproductive Function in Male RabbitsJournal of Andrology, 2007
- Stereological Evaluation of Human Spermatogenesis after Suppression by Testosterone Treatment: Heterogeneous Pattern of Spermatogenic ImpairmentJournal of Clinical Endocrinology & Metabolism, 1998
- Spermatogenesis is Accelerated in the Immature Djungarian and Chinese Hamster and RatBiology of Reproduction, 1993
- STATISTICAL METHODS FOR ASSESSING AGREEMENT BETWEEN TWO METHODS OF CLINICAL MEASUREMENTThe Lancet, 1986
- Quantification of the Human Sertoli Cell Population: Its Distribution, Relation to Germ Cell Numbers, and Age-Related Decline 1Biology of Reproduction, 1984
- EXCRETION PATTERN OF LABELLED SPERMATOZOA AND THE TIMING OF SPERMATOZOA FORMATION AND EPIDIDYMAL TRANSIT IN RABBITS INJECTED WITH THYMIDINE-3HReproduction, 1965
- CYTOLOGY AND KINETICS OF SPERMATOGENESIS IN THE RABBITReproduction, 1963
- Spermatogenesis in Man: An Estimate of Its DurationScience, 1963