In this research, scientists studied how giving thyroid hormone to baby rats affects their stress hormones and growth hormones as they grow up. They found that giving the hormone increased the stress hormone levels of the baby rats by day 4 and kept them higher by day 12. The baby rats with the hormone had lower growth hormone levels than those without it, particularly when they were stressed. This shows that thyroid hormone given in early life can change how stress and growth hormones develop in rats.