What first tier hormone stimulates cortisol production?

ACTH

https://www.hormone.org/your-health-and-hormones/glands-and-hormones-a-to-z/hormones/adrenocorticotropic-hormone-acth

lizards have adapted to life in the desert. some desert lizards have toes with spiny scales to them run across the sand without sinking. some use the sand to hide from predators, or to search for small animals that they prey upon.