The endocrine system is a complex system consisting of glands in the body that produce hormones. Examples are the thyroid gland in the throat, the pituitary gland in the brain, the adrenals, pancreas and ovaries in the abdomen, and the testicles, which lie outside the abdomen.
Hormones act as chemical messengers, controlling many basic functions, such as growth, development, reproduction, how food is utilised in the body, blood pressure, blood glucose levels and fluid balance. Examples of hormones are insulin from the pancreas, which controls blood glucose, and the sex hormones, oestrogen from the ovary and testosterone from the testicles, which affect reproductive function.
Hormones are carried in the blood stream to distant target organs or cells where they perform particular functions. Examples are the pituitary hormone from the brain which causes the ovary to release an egg, or the hormones from the adrenal gland which prepare the body to face stress. Other hormones are released within an organ or tissue – a collection of cells related by their functions – and act locally within the organ or tissue, such as preventing an egg maturing in the ovary.
The endocrine system also includes a third group of hormones called ‘neurohormones’ which are released by nerve cells either locally or into the blood stream where they act further away.
Endocrine disruption is not, in itself, a measure of toxicity – the occurrence of adverse health effects. Rather, it is considered to be a change that may lead to harmful effects. For example, a potential endocrine disruptor (pED) is a foreign substance or mixture that possesses properties that might be expected to lead to endocrine changes in an individual life form, in its offspring, or in populations.
An endocrine disruptor (ED) is, therefore, defined as a foreign substance or mixture that alters function(s) of the endocrine system, consequently harming an individual life form, its offspring, or populations
How do EDCs act? Endocrine disrupting chemicals (EDCs) can act in a number of ways in different parts of the body, they may:
- Reduce the production of hormones in endocrine glands
- Affect the release of hormones from endocrine glands
- Copy or counteract the action of hormones at target tissues, or
- Speed up the metabolism of hormones and so reduce their action.
In many cases, it is not yet clear exactly how EDCs act, even in some cases where a link has been shown between EDC exposure and an adverse effect.
What has been established mainly in the laboratory is:
- Exposure to EDCs during early development (e.g. in the womb, during childhood) may cause permanent effects
- Exposure to EDCs during adult life may not show any significant or visible effects
- Exposure to EDCs may produce varying effects depending upon the stage of the life cycle or even the season, and unforeseen effects may occur in the target tissues due to endocrine interactions.
The most controversial issue is whether low level exposures to EDCs can have adverse effects. Some scientists have found effects at low doses in laboratory experiments, while others have not been able to corroborate these findings. Some say that traditional testing methods are not robust enough to pick up low-dose effects. These are important issues to resolve because of the presence of low levels of EDCs in the environment.
What does all this mean to you the boater? It is really hard to say. Exposure to the water in the river MAY present a hazrd on some level. Some potential EDCs may be absorbed into the body via the your skin layers, exposed orifices (e.g. mouth, nasal passages, ears, etc.). The biggest concern may be with any compounds previously processed with DSMO. DSMO acts as a carrier for the chemical compound attached to it and allows instant transfer of that chemical into the human body.