Toxicology 10 – Endocrine disruption
The endocrine system; use hormones to transmit signals/information from 1 cell to
another
Hormones are messengers that are produced by endocrine glands and tissues. They
are secreted into the blood and transported to organs where they bind to receptor
and regulate physiology and behavior.
Chemically classes of hormones;
Peptide hormones; insulin, glucagon and adrenaline
Steroid hormones; oestrogen and testosterone
Biological classification of hormones
Releasing hormones; hypothalamus pituitary (hypofyse)
Stimulation (or tropic) hormones; pituitary endocrine tissue (gland)
Non-tropic hormones; endocrine tissue (gland) target cell
Gonadotropic hormones;
FSH; follicle stimulating hormone
LH; luteinizing hormone
Sex hormones;
E2; estradiol
T; testosterone
DHT; dihydrotestosterone
2 kinds of hormone receptors;
Membrane receptor; peptide hormone, extracellular,
hormone receptor binding activated second
messenger system in target cell
Nuclear receptors steroid hormone, intracellular, hormone
receptor complex activates cell itself
Endocrine disrupter; is an exogenous (van buitenaf) substance or mixture that alters
function of the endocrine system and consequently causes adverse health effect in
an intact organism or its progeny (nageslacht) or (sub)populations
Endocrine disruption can only be tested in vivo, the organism has to be alive to test
the endocrine disruption.
Examples; personal care products, handsoaps, toothpaste
Effects; cancer, obesity, fertility (vruchtbaarheid) reduces.
Examples of EDC effects in wildlife;
Adverse effects on reproduction due to egg shell tinning by DDT and other
pesticides
Reduced reproduction and immune function by PCB/DDT and dioxins
Distorted sex organ development by DDT
Most important modes of action of endocrine disruption chemicals (EDC);
The endocrine system; use hormones to transmit signals/information from 1 cell to
another
Hormones are messengers that are produced by endocrine glands and tissues. They
are secreted into the blood and transported to organs where they bind to receptor
and regulate physiology and behavior.
Chemically classes of hormones;
Peptide hormones; insulin, glucagon and adrenaline
Steroid hormones; oestrogen and testosterone
Biological classification of hormones
Releasing hormones; hypothalamus pituitary (hypofyse)
Stimulation (or tropic) hormones; pituitary endocrine tissue (gland)
Non-tropic hormones; endocrine tissue (gland) target cell
Gonadotropic hormones;
FSH; follicle stimulating hormone
LH; luteinizing hormone
Sex hormones;
E2; estradiol
T; testosterone
DHT; dihydrotestosterone
2 kinds of hormone receptors;
Membrane receptor; peptide hormone, extracellular,
hormone receptor binding activated second
messenger system in target cell
Nuclear receptors steroid hormone, intracellular, hormone
receptor complex activates cell itself
Endocrine disrupter; is an exogenous (van buitenaf) substance or mixture that alters
function of the endocrine system and consequently causes adverse health effect in
an intact organism or its progeny (nageslacht) or (sub)populations
Endocrine disruption can only be tested in vivo, the organism has to be alive to test
the endocrine disruption.
Examples; personal care products, handsoaps, toothpaste
Effects; cancer, obesity, fertility (vruchtbaarheid) reduces.
Examples of EDC effects in wildlife;
Adverse effects on reproduction due to egg shell tinning by DDT and other
pesticides
Reduced reproduction and immune function by PCB/DDT and dioxins
Distorted sex organ development by DDT
Most important modes of action of endocrine disruption chemicals (EDC);
