Related Experiment Video
Updated: Aug 8, 2026

In vivo Characterization of Endocrine Disrupting Chemical Effects via Thyroid Hormone Action Indicator Mouse
Published on: October 6, 2023
Acetylcholine and norepinephrine: compared actions thyroid metabolism
Abstract:
Acetylcholine (ACh; 5 X 10(-4) M), like norepinephrine (NE; 6 X 10(-6) M), as shown previously, stimulated iodide organification by mouse thyroids in vitro, while at the same time it inhibited TSH- or (Bu)2cAMP-induced T4 release. However, thyroid cAMP was not changed by ACh, suggesting that ACh, like NE, exerted its effects at a step beyond cAMP production. Also, while ACh increased cGMP concentrations, (Bu)2cGMP and 8-bromo-cGMP were not effective on thyroid function in this system. Neurotransmitters, then, presumably do not exert their action through cyclic nucleotide stimulation ACh-induced stimulation of organification and inhibition of release was reversed by 10(-5) M atropine (ATR) but not by 10(-5) M d-tubocurarine, indicating that muscarinic receptors were involved. ATR also reversed inhibition of T4 release induced by NE, suggesting that the presynaptic cholinergic pathway may be responsible for stimulation of postsynaptic cholinergic and adrenergic neurotransmitters in the thyroid gland.
More Related Videos
Related Concept Videos
Direct-Acting Cholinergic Agonists: Chemistry and Structure-Activity Relationship
The direct-acting...
Adrenergic Neurons: Neurotransmission
Synthesis: Catecholamine synthesis requires tyrosine, which is taken...
Adrenergic Agonists: Indirect-Acting Agents
One mechanism involves depleting stored catecholamines by displacing them from synaptic vesicles. These agents, known as "displacers," are transported into vesicles at the expense of noradrenaline. Examples include amphetamine and tyramine, which lack a catechol moiety, resulting in prolonged action, improved oral bioavailability, and...
Adrenergic Agonists: Mixed-Action Agents
Ephedrine and pseudoephedrine lack a catecholamine group, making them less susceptible to degradation by metabolic enzymes. They have increased oral bioavailability and lipophilicity, resulting in a longer duration of action. Their response is reduced by...
Synthesis and Regulation of Thyroid Hormones
Upon reaching the thyroid gland, TSH stimulates the follicular cells' active uptake of iodide ions from the blood. The ions diffuse to the apical surface of the cells and are oxidized to iodine. The iodine is then...
Functions of Thyroid Hormones
TH is indispensable for the normal development and maturation of the skeletal, muscular, and nervous systems during fetal and childhood growth. It facilitates bone mineral turnover and regulates protein synthesis in developing tissues, contributing significantly to overall growth and...

