| Susceptible Periods during Embryogenesis of the Heart and Endocrine Glands T.W. Sadler Department of Cell Biology and Anatomy, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA Abstract
One of the original principles of teratology states that, "Susceptibility to teratogenesis varies with the developmental stage at the time of exposure to an adverse influence" [Wilson JG. Environment and Birth Defects. New York:Academic Press, 1973]. The time of greatest sensitivity encompasses the period of organ formation during weeks 3-8 following fertilization in human gestation. At this time, stem cell populations for each organ's morphogenesis are established and inductive events for the initiation of differentiation occur. Structural defects of the heart and endocrine system are no exception to this axiom and have their origins during this time frame. Although the function and maturation of these organs may be affected at later stages, structural defects and loss of cell types usually occur during these early phases of development. Thus, to determine critical windows for studying mechanisms of teratogenesis, it is essential to understand the developmental processes that establish these organs. Key words: adrenal glands, embryology, heart, pancreas, parathyroid, pituitary, thymus, thyroid. -- Environ Health Perspect 108(suppl 3) :555-561 (2000) . http://ehpnet1.niehs.nih.gov/docs/2000/suppl-3/555-561sadler/abstract.html
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