CortisolAll lipid-soluble hormones are synthesized from cholesterol. Cortisol, a lipid-soluble hormone, is secreted by the adrenal cortex. All water-soluble hormones are formed from amino acids. Insulin, prolactin, and growth hormone are water-soluble hormones. Insulin is secreted by the pancreas. Prolactin and growth hormone are also secreted by the pituitary gland.