Exposure to thiourea during the early stages of development impedes the formation of the swim bladder in zebrafish larvae.

Thiourea, a widely used agrochemical, is known to inhibit the activity of thyroid peroxidase, a key enzyme in the biosynthetic pathway of thyroid hormones. Thyroid insufficiency compromises the basal metabolic rate in warm-blooded organisms and embryonic development in vertebrates. In this study, we looked for developmental defects by exposing the zebrafish embryos to an environmentally relevant dose of thiourea (3 mg/mL).