The site of action for \(\alpha\)-MSH is a. muopioid receptors b. melanocortin-1 receptors c. glucocorticoid receptors d. melatonin receptors e. ACTH receptors

α-MSH is a hormone produced in the pituitary gland, which stimulates the production of melanin in melanocytes. Melanin is responsible for the pigmentation of skin, hair, and eyes. α-MSH is involved in regulating various physiological processes such as skin pigmentation, appetite regulation, and sexual behavior.

Now, let's look at each option and evaluate if it is the correct receptor for α-MSH: a. muopioid receptors - These receptors are primarily involved in analgesia and are targeted by opioids like morphine. α-MSH has no significant interaction with this receptor. Incorrect. b. melanocortin-1 receptors - These receptors are G-protein coupled receptors that bind melanocortin hormones, including α-MSH. They play a crucial role in skin pigmentation, as they control the production of melanin in melanocytes. Correct. c. glucocorticoid receptors - These receptors are associated with the regulation of glucose metabolism and immune response, and primarily bind glucocorticoid hormones like cortisol. α-MSH doesn't target this receptor. Incorrect. d. melatonin receptors - These receptors primarily bind melatonin, a hormone involved in the regulation of sleep-wake cycles. α-MSH doesn't interact with this receptor. Incorrect. e. ACTH receptors - These receptors bind adrenocorticotropic hormone (ACTH), which stimulates the production of cortisol in the adrenal gland. α-MSH is derived from the same precursor molecule as ACTH, but it binds to a different receptor. Incorrect.

Based on the evaluation of each option, the correct answer is: b. melanocortin-1 receptors