Zoology - Chemical Coordination and Integration Question with Solution | TestHub

Hormones bind to specific hormone receptors (proteins) which are of two types mainly:
A. Membrane-bound receptors (present on the cell membrane of the target cells) - Those hormones (protein or peptide) which bound to the membrane-bound receptors usually do not enter the target cell but generate second messengers like cyclic AMP,${\mathrm{I}\mathrm{P}}_3,\mathrm{ }{\mathrm{C}\mathrm{a}}^{++}$, etc. which in turn regulate cellular metabolism.
B. Intracellular receptors (receptors present inside the target cells - mostly nuclear receptors) - Hormones (e.g. steroid hormones, iodothyronines, etc.) which bound to intracellular receptors, usually regulate gene expression or chromosome function by the interaction of the hormone-receptor complex with the genome. Various biochemical actions occur resulting in physiological and developmental effects.