Non-steroid HormonesDerived from amino acids, including peptides and proteins. Water-soluble (hydrophilic). Cannot pass through the cell membrane directly. Bind to receptors on the cell surface membrane. Binding to the receptor activates an enzyme, which then activates a second messenger inside the cell, leading to various cellular responses. Examples: Insulin, glucagon, epinephrine (adrenaline), thyroid hormones, nor, Oxytocin, ADH, GH, TSH, ACTH, FSH, LH, PRL, Calcitonin, PTH, melatonin, glucagon, insulin, hCG, leptin, resistin, gastrin, secretin, ANP, Erythropoietin, osteoclacin, Thymus hormones..