Solution:
Thyrocalcitonin is a water-soluble (peptide) hormone and binds to membrane-bound receptors and leads to the generation of a second messenger (cyclic AMP) inside the target cells.
For example, it inhibits the activity of osteoclasts.
Thyroxine, cortisol and estradiol (estrogen) are lipid-soluble hormones and enter the target cells.
They bind to intracellular receptors and influence gene expression.
