Over the last decades, acrosomal exocytosis (also called the “acrosome reaction”) has been recognized as playing an essential role in fertilization. Secretion of this granule is an absolute requirement for physiological fertilization. In recent years, the study of mammalian acrosomal exocytosis has yielded some major advances that challenge the long-held, general paradigms in the field. Principally, the idea that sperm must be acrosome-intact to bind to the zona pellucida of unfertilized eggs, based largely on in vitro fertilization studies of mouse oocytes denuded of the cumulus oophorus, has been overturned by experiments using state-of-the-art imaging of cumulus-intact oocytes and fertilization experiments where eggs were reinseminated by acrosome-reacted sperm recovered from the perivitelline space of zygotes. From a molecular point of view, acrosome exocytosis is a synchronized and tightly regulated process mediated by molecular mechanisms that are homologous to those reported in neuroendocrinal cell secretions. The authors provide a broader perspective, focusing on a limited number of important topics that are essential for understanding the molecular mechanisms governing this step in the fertilization process. They also discuss molecular aspects such as the signaling pathways leading to exocytosis, including the participation of ion channels, lipids, the fusion machinery proteins and the actin cytoskeleton as well as cellular aspects such as the site of acrosomal exocytosis and the use of gene-manipulated animals to study this process.

Biology of Fertilization, Volume 2: Biology of the Sperm is the second in a three-volume series that brings together various lines of research about reproduction in general and fertilization in particular. It is devoted to spermatogenesis, sperm physiology, and the initial interactions of sperm with egg components. The book is organized into three parts. Part I on spermatogenesis and sperm physiology includes studies on the evolution of the sperm cell; regulatory mechanisms, sperm antigen differentiation, and maturation of sperm in the reproductive tracts in mammals; physicochemical mechanisms of the acrosome filament extrusion process; and enzymes associated with sperm cell function. Part II deals with chemotaxis in microorganisms: bacteria and slime molds. Part III on gamete recognition and binding includes studies on identifying, isolating, and characterizing specific sperm and egg surface components involved in sperm-egg interaction; fertilization in the alga Fucus; fertilization in insects; and the role of lysins in fertilization.

This valuable reference work provides a synthesis of the latest knowledge about the acrosomatic reaction of human sperm. The acrosomatic reaction, which is a fundamental step in the process of fertilisation, is examined on both the fundamental and clinical levels. Three very recent aspects are also dealt with: what happens to the acrosome during intracytoplasmic microinjections, the usefulness of screening spermatozoa that have completed their acrosomatic reaction, and the development of contraception by a vaccine that targets one of the proteins of the acrosome. International Symposium, Collioure, France, September 1995.

Mammalian spermatozoa have complex structures. The structure-function relationship of sperm has been studied from various viewpoints. Accumulated evidence has shown that the sperm components undergo sequential changes from the beginning of spermatogenesis to the time of fertilization/embryogenesis. Structural analyses have been performed using various new techniques of light and electron microscopy as well as immunohistochemistry and immunocytochemistry in combination with specific probes such as antibodies against sperm components. Recently developed gene-manipulation techniques have accelerated investigations on the events that govern the relationship between the structure and molecular components of sperm. In addition, animal models with gene manipulations have been shown to exhibit various morphological and functional abnormalities that lead to infertility. In this book, I discuss the events that occur in the normal sperm head and govern the structure-function relationship from the time of spermatogenesis to that of fertilization or egg activation. In this regard, I describe dynamic modifications and maturation events occurring in sperm-head components and compare the outcomes of these events with the outcomes of their failure.

Focusing on modern sperm function testing, this guide is essential in selecting sperm that will produce viable and healthy embryos.

The epididymis has become increasingly important to researchers engaged in fertility and its regulation. Until now, no single volume review of the field has been available. The Epididymis: From Molecules to Clinical Practice A Comprehensive Survey of Efferent Ducts, The Epididymis and the Vas Deferens will provide a complete, up-to-date, in-depth review of the research on the male reproductive tract. Structure, function, and molecular mechanisms underlying the control of the efferent ducts, epididymis, and vas deferens will be reviewed.

Written by experts in their respective fields, this book reviews the expanding knowledge concerning the mechanisms regulating male reproduction at the molecular and cellular levels. It covers the development of the testes and regulatory controls for spermatogenesis and steroidogenesis, and it considers aspects of Sertoli cell function. Areas of emphasis include communication between the various cell types involved in reproduction by hormone and growth factors and the mechanisms by which these factors regulate gene expression. A number of mammalian systems, including humans, are covered. The carefully selected authors provide a clear synopsis of the concepts in each area as well as the latest references, enabling the reader to investigate the topic further. This book is of interest to those seeking an understanding of the regulatory mechanisms in male reproduction and is written for the graduate and postgraduate levels. Provides up-to-date reviews of the molecular and cellular biology of male reproduction Includes chapters on the developmental biology of the testes Links conventional hormonal control of testicular function with the evolving role of growth factors and proto-oncogenes