Encocrine disrupting compounds Flashcards
what is an endocrine disrupting compound
exogenous substance or mixture that alters function (s) of the endocrine system and consequently causes adverse health effects in an intact organism, its progeny or sub populations
What evidence support endocrine disruptors’ existence
comes from changes seen in wildlife species - effects found in molluscs, crustacea, fish, reptiles, birds and mammals
there is evidence in humans through intentional or accidental exposure to high levels of particular chemicals
what are some examples of EDCs
natural hormones = from any animal, released into the environment, and chemicals produced by one species that exert hormonal actions on other animals
natural chemicals - toxins produced by components of plants
synthetically produced pharmaceuticals - intended to be highly
hormonally active
man-made chemicals - by porducts released into the environement
why does the dose of the toxin matter
all chemicals are toxic and the adverse effect of a toxin is proportional to the dose
because of this it is also assumed that there are no effects at exposures below the lowest obverse effect level
what is a u shaped non monotonic dose-response curve
with maximal responses of the measured endpoint observed at low and high doses
what is an inverted u shaped non monotonic dose-response curve
with maximal responses observed at intermediate doses
what is considered physiological dose
the amount of free endogenous hormone that the EDC is mimicking or antagonizing
what is considered toxicological dose
identified by some measures of toxicity, such as death, decreases body weight or malformations
what is considered environmentally relevant dose for an edc in a research study
established for chemicals where there is information concerning levels monitored in air food or water
why does timing matter
different effects at different periods of development
knowledge of the organizational vs activational effects of hormones also make it possible to understand why EDCs can have very different effects depending on the timing of exposure
as different organs have different times of vulnerability to hormones and EDCs there can be permanent, adverese consequences of exposures if they occur during critical periods
what is organizational effects
structural changes that typically take place during development and which are usually irreversible
what is activational effects
transient effects of hormones on systems, usually in the mature organism (in brains like neurotransmitters)
