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Reproductive System and Mammary Gland
Citation:
Vidal, J., Charles E. Wood, K. Colman, K. Whitney, AND D. Creasy. Reproductive System and Mammary Gland. Edition 2, Chapter 20, Pritam S. Sahota, James A. Popp, Jerry F. Hardisty, Chirukandath Gopinath, Page Bouchard (ed.), Toxicologic Pathology: Nonclinical Safety Assessment. CRC Press - Taylor & Francis Group, LLC, Boca Raton, FL, , 132, (2018). https://doi.org/10.1201/9780429504624
Impact/Purpose:
The U.S. EPA has a broad mandate to characterize the biological effects of chemicals of public health and environmental concern. An important way in which the Agency meets this goal is through review of nonclinical pathology data, submitted as part of testing programs for pesticides and other toxic substances. The identification of reproductive system effects is a key component of these toxicity assessments, particularly for chemicals with potential endocrine-disrupting effects. This chapter documents pathological findings in the reproductive tract and mammary gland of common nonclinical species used in toxicology. These effects can be critical to the development of pharmaceuticals and the assessment of environmental chemicals for potential endocrine-disrupting effects. There are many unique considerations when evaluating the reproductive system. Life stage changes, background lesions, and hormonal cyclicity can all confound proper identification and interpretation of treatment effects. In addition to morphologic descriptions, this review provides relevant information on normal anatomy, physiology, endocrinology, and other biological factors that will help in distinguishing normal variation from treatment-induced changes and determining whether a particular outcome is relevant to human health. This chapter also presents different issues in reproductive toxicology faced by pathologists, from challenges in juvenile and immature animals to changes associated with senescence, with emphasis on stage-aware assessments. More broadly, this book should serve as a practical reference for toxicologic pathologists, toxicologists, and health authority scientists involved in nonclinical safety assessment.
Description:
This chapter provides more information on normal anatomy, histology, physiology, and endocrinology of Reproductive System and Mammary Gland. Compound-related effects on the reproductive system can be pivotal in pharmaceutical development. It considers the male and female reproductive systems together with the mammary gland as many basic concepts track across these organ systems. Embryological development of the reproductive tract is broadly similar species but there are detailed differences, particularly in the timing of events. The development of xenobiotic-induced endometrial hyperplasia in rodents has been reported in numerous studies of animals exposed in utero, prepubertally, or after ovariectomy. Postnatal testicular development varies among species, just as the timing of puberty varies. The term "puberty" denotes the time period encompassing hormonal changes, development of sexually dimorphic traits, and the achievement of fertility. Considerable confusion exists regarding the terminology of sexual maturation.
