Glossary

Additive effect = A biologic response to exposure to multiple substances that equals the sum of responses of all the individual substances added together.

Adipocyte = A cell specialized in storage of fat.

Adverse effect = A change in morphology, physiology, growth, reproduction, development, or lifespan of an organism that results in impairment of functional capacity or impairment of capacity to compensate for additional stress or increased susceptibility to the harmful effects of other environmental influences.

Agonist = A ligand that binds to and activates a receptor and elicits a physiological response.

Allosteric = Activity of an enzyme that results from combination with a substance at a point other than the chemically active site.

Androgen = A sex steroid hormone that stimulates or controls the development and maintenance of male characteristics in vertebrates by binding to androgen receptors, for example, testosterone.

Anogenital distance = The distance from the anus to the genitalia, the base of the penis or vagina.

Antagonist = Any ligand that blocks binding of endogenous agonists to the receptor, thereby modulating receptor activity.

Antiandrogen = Chemicals that acts as an antagonist at the androgen receptor or otherwise interferes with the effects of endogenous androgens.

Bioaccumulation = Accumulation of a toxic substance in various tissues of a living organism. Bioaccumulation occurs when the rate of intake of a substance is greater than the rate of excretion or metabolic transformation of that substance.

Cell division = Separation of a cell into two daughter cells – in higher eukaryotes, it involves division of the nucleus (mitosis) and the cytoplasm (cytokinesis); mitosis often is used to refer to both nuclear and cytoplasmic division.

Chromatin = A DNA–protein complex consisting of chromosomes. Histones are the primary protein components of chromatin that serve to compact the tightly coiled DNA.

Cryptorchidism = Testicular nondescent (failure of testicular descent into the scrotum).

Developmental toxicity = Any adverse effect induced prior to attainment of adult life including effects induced or manifested in the embryonic or fetal period and those induced or manifested postnatally.

DNA methylation = A key epigenetic mechanism involving the biochemical process of the conversion of cytosine (within a CpG dinucleotide) into 5-methyl cytosine in DNA, which has the effect of reducing gene expression.

End point = Measurable parameter that indicates a preceding exposure or the effect of a chemical; it constitutes one of the target observations of the trial.

Epidemiology = Study of disease distribution in defined populations, and of factors that influence the occurrence of disease including environmental and personal characteristics.

Epididymis = A coiled tube through which sperm exits the testes.

Epigenetics = The study of factors that influence heritable changes to gene expression without alterations to the underlying DNA sequence, mostly mediated by DNA methylation and histone modifications.

Endogenous = Naturally occurring or produced within an organism.

E-Screen = Human breast cancer cell proliferation assay that measures growth of MCF-7 cells in vitro in response to endocrine substances.

Exogenous = Not naturally occurring or produced within an organism.

Fertility = Reproductive competence.

Gametes = Reproductive cells that unite during sexual reproduction to form a new cell called a zygote. In humans, male gametes are sperm and female gametes are ova (eggs).

Gametogenesis = Germ-line-specific epigenetic reprogramming.

Germ cells = The spermatozoa and their precursors in males or the ova [eggs] and their precursors in females.

Gonad = Ovaries in females, testes in males; an organ that produces cells and hormones necessary for reproduction.

Histone = A family of simple proteins, abundant in the cell nucleus and constituting a substantial part of the protein-and-DNA complex known as chromatin.

Hormone = Any extracellular substance that induces specific responses in target cells. Coordinate the growth, differentiation, and metabolic activities of various cells, tissues, and organs in multicellular organisms.

Homeostasis = Physiological processes that maintain the internal environment of the body in balance.

Hoxa10 = An estrogen-regulated gene necessary for uterine development and pregnancy.

Hypospadias = Penile malformations (an abnormality of development of the penis in which the urethra does not open at the tip of the organ).

Hypothalamus– pituitary–gonadal axis = The reproductive system of vertebrates, comprising the hypothalamus at the base of the brain, the anterior pituitary gland, and the gonads (ovary or testis).

Imposex = A type of intersexuality, in which females develop male sexual organs.

Imprinting = A process by which one allele of a gene is expressed from the parental genome. Specifically, one allele of a gene is silenced by epigenetic mechanisms, resulting in expression of only the paternal or maternal allele of a gene. These epigenetic patterns are determined in the germ cells and inherited in the next generation.

Inheritance = Transmission of information between generations of an organism.

In utero = An event occurring within the uterus of a mammal during pregnancy; describes the state of an embryo or fetus.

In vitro = Biological study outside of a living organism, in a controlled environment such as in a cell culture or in cells grown in a petri dish.

In vivo = Experimentation using a whole living organism.

Lydig cell = The testosterone producing cells of the testis.

Malformation = A permanent alteration (abnormality) in which there is a morphologic defect of an organ or a larger region of the body, resulting from an abnormal developmental process and/or will adversely affect survival, growth, or development of functional competence.

MicroRNA (miRNA) = Small lengths of RNA that are not translated into proteins.

Narcosis = A disturbance in the cell membrane permeability by hydrophobic chemicals.

Neonatal = The newborn infants.

Nuclear receptor = General term for intracellular receptors whose members reside in the nucleus that bind lipid-soluble hormones (e.g., steroid hormones); they can bind directly to DNA, either activating or repressing gene expression. Nuclear receptors are therefore transcription factors.

Parabens = p-Hydroxybenzoates – preservatives.

Perinatal = Period leading up to birth and after.

Plasma membrane = The membrane surrounding a cell that separates the cell from its external environment, consisting of a phospholipid bilayer and associated proteins.

Pleiotropic = Producing more than one effect.

Precautionary principle = Where there are threats of serious or irreversible damage, lack of full scientific certainty shall not be used as a reason for postponing cost-effective measures to prevent environmental degradation.

Preputial separation = Separation of the foreskin of the penis from the glans penis.

Puberty = Bodily changes of sexual maturation, such as vaginal opening or balanopreputial separation.

Receptor (cell receptor) = A protein molecule, embedded in either the plasma membrane or the cytoplasm of a cell that binds a specific extracellular signaling molecule (ligand) and then initiates a cellular response. Receptors for steroid hormones, which diffuse across the plasma membrane, are located within the cell; receptors for water-soluble hormones, peptide growth factors, and neurotransmitters are located in the plasma membrane with their ligand-binding domain exposed to the external medium.

RNA interference = A mechanism that inhibits gene expression at the stage of translation or by hindering the transcription of specific genes. This method has been referred to as post-transcriptional gene silencing and is an important tool for gene expression.

Reproductive toxicity = Structural and/or functional alterations that may affect reproductive competence in sexually mature males and females, manifested as impairment of fertility, parturition, or lactation.

Signal transduction = Conversion of a signal from one physical or chemical form into another. In cell biology, it commonly refers to the sequential process initiated by binding of an extracellular signal to a receptor and culminating in one or more specific cellular responses.

Seminal vesicles = Pouches located above the prostate that store semen.

Spermatogenesis = The process initiated in the male testis with the beginning of puberty of sperm cell development.

Steroidogenesis = The biological synthesis of steroid hormones.

Sustainability = Attaining a society and environment that can meet its current needs while preserving the ability of future generations to meet their needs (Brundtland Commission)

Testicular dysgenesis syndrome = Spectrum of reproductive disorders that originate in male fetal life including poor sperm quality (impaired spermatogenesis), cryptorchidism,...