European Hormone Medal

Josef Köhrle

European Hormone Medal

Awarded to an international scientist for significant contributions to basic or clinical endocrinology

Great impact in low quantities: thyroid hormones, trace elements and endocrine disruptors

Thyroid hormones regulate development (especially of the brain), growth, body temperature and metabolic pathways. Do their blood concentrations inform us about their action and consequences for the individual? Not really! Their follicular biosynthesis and storage, protein-protected distribution via the bloodstream, specific transport across cellular membranes, intracellular (in)activation and/ or metabolism have been revealed. Thus, in 2022, we are facing a remarkably variable subcellular scenery, contributing to the prereceptor control of local tri-iodothyronine (T3) availability to intracellular T3 receptors. These act as ligand-modulated transcription factors for gene expression.

Endogenous and exogenous signals efficiently and bidirectionally influence all these steps, eventually resulting in the permissive mode of thyroid hormone action. Too little or too much T3 at the wrong spot or the wrong time severely impairs health, quality of life and integrity of an individual. That’s what we have learned from amphibian metamorphosis or deficiencies of essential trace elements (iodine, selenium, iron, zinc) required for this thyroid hormone multistage machinery. Evolution successfully took advantage of the ‘exotic’ element iodine as a key constituent of a potent hormone acting at tiny, local concentrations. Considering that the anthropogenic mass recently exceeded our blue planet’s biomass, we must minimise exposure to endocrine disruptors that already interfere at low concentrations with the thyroid hormone system.

‘We must minimise exposure to endocrine disruptors that already interfere at low concentrations with the thyroid hormone system.’