Towards a science-based testing strategy to identify maternal thyroid hormone imbalance and neurodevelopmental effects in the progeny-part III: how is substance-mediated thyroid hormone imbalance in pregnant/lactating rats or their progeny related to neurodevelopmental effects?
Crit Rev Toxicol
; 52(7): 546-617, 2022 08.
Article
en En
| MEDLINE
| ID: mdl-36519295
This review investigated which patterns of thyroid- and brain-related effects are seen in rats upon gestational/lactational exposure to 14 substances causing thyroid hormone imbalance by four different modes-of-action (inhibition of thyroid peroxidase, sodium-iodide symporter and deiodinase activities, enhancement of thyroid hormone clearance) or to dietary iodine deficiency. Brain-related parameters included motor activity, cognitive function, acoustic startle response, hearing function, periventricular heterotopia, electrophysiology and brain gene expression. Specific modes-of-action were not related to specific patterns of brain-related effects. Based upon the rat data reviewed, maternal serum thyroid hormone levels do not show a causal relationship with statistically significant neurodevelopmental effects. Offspring serum thyroxine together with offspring serum triiodothyronine and thyroid stimulating hormone appear relevant to predict the likelihood for neurodevelopmental effects. Based upon the collated database, thresholds of ≥60%/≥50% offspring serum thyroxine reduction and ≥20% and statistically significant offspring serum triiodothyronine reduction indicate an increased likelihood for statistically significant neurodevelopmental effects; accuracies: 83% and 67% when excluding electrophysiology (and gene expression). Measurements of brain thyroid hormone levels are likely relevant, too. The extent of substance-mediated thyroid hormone imbalance appears more important than substance mode-of-action to predict neurodevelopmental impairment in rats. Pertinent research needs were identified, e.g. to determine whether the phenomenological offspring thyroid hormone thresholds are relevant for regulatory toxicity testing. The insight from this review shall be used to suggest a tiered testing strategy to determine whether gestational/lactational substance exposure may elicit thyroid hormone imbalance and potentially also neurodevelopmental effects.
Palabras clave
OECD TG 443); Thyroxine (T4); acoustic startle response; adverse outcome pathway (AOP); cognitive function (learning and memory); deiodinase (DIO); developmental neurotoxicity (DNT) study (OECD TG 426); extended one generation reproductive toxicity study (EOGRTS; mode-of-action (MoA); motor activity; sodium-iodide symporter (NIS); thyroid hormone clearance; thyroid peroxidase (TPO); triiodothyronine (T3); uridine diphosphate glucuronyltransferase (UGT)
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Glándula Tiroides
/
Enfermedades del Sistema Endocrino
Tipo de estudio:
Prognostic_studies
/
Qualitative_research
Límite:
Animals
/
Pregnancy
Idioma:
En
Revista:
Crit Rev Toxicol
Asunto de la revista:
TOXICOLOGIA
Año:
2022
Tipo del documento:
Article
País de afiliación:
Estados Unidos
Pais de publicación:
Reino Unido