GENERAL HISTOLOGY

Detailed explanation-1: -Although steroid and thyroid hormones are neither structurally nor biosynthetically related, the existence of a common structure for their receptors supports the proposal that there is a large superfamily of genes whose products are ligand-responsive transcription factors.

Detailed explanation-2: -Most endocrine hormones are non-steroid hormones, including insulin and thyroid hormones. A non-steroid hormone binds with a receptor on the plasma membrane of a target cell. Then, a secondary messenger affects cell proces ses.

Detailed explanation-3: -Thyroid Hormone Transport and Metabolism Circulating thyroid hormones are more than 99% bound to three classes of plasma proteins. Thyroxine-binding globulin (TBG) functions as the principal transport protein.

Detailed explanation-4: -Thyroid hormone actually represents the combination of the two main hormones that your thyroid gland releases: thyroxine (T4) and triiodothyronine (T3). They’re often collectively referred to as “thyroid hormone” because T4 is largely inactive, meaning it doesn’t impact your cells, whereas T3 is active.

Detailed explanation-5: -The mechanism of action of the thyroid hormones is similar; they interact with intracellular receptors. Both the steroid and thyroid hormone-receptor complexes exert their action by binding to specific nucleotide sequences in the DNA of responsive genes.