1. Thyroid hormones exert their effects on cells in a manner similar to steroid hormones; describe the mechanism of action of thyroid hormones.

Thyroid hormones diffuse through the plasma and enter the cell nucleus. The hormone will then bind to specific receptors for the hormone inn the nucleus forming a thyroid hormone receptor complex. This action later binds to specific regions of the DNA known as responsive element which results in increase in transcription of certain genes. Every binding is unique in the way they form and bind. An increase in gene transcription means an increase in amount of mRNA.