Melanocyte-Stimulating Hormone (MSH)


Melanocyte-Stimulating hormone (MSH) characterizes a group of hormones made by the pituitary gland, hypothalamus, and skin cells. MSH is essential for preserving the skin from ultraviolet rays, the development of pigmentation, and controlling appetite. 

What does MSH Do?

Ultraviolet (UV) rays, increase MSH production by the skin and pituitary gland. It has a vital role in making pigmentation (coloring) of the skin, hair, and eyes. Specialized skin cells known as melanocytes produce melanin, which helps protect cells from skin cancer. 

Skin coloring (pigmentation) is the central role of MSH, but MSH made in the hypothalamus also works to suppress appetite. The hormone leptin further enhances the latter. 

MSH also affects other bodily processes. It helps regulate the hormone aldosterone and has other anti-inflammatory effects. 

MSH produced from the pituitary gland is increased by being exposed to UV light. 

What Problems Can Occur with MSH?

Having high levels of MSH leads to increased production of melanin. This enhancement occurs due to long-term sun exposure or tanning. People with very light skin often make less melanin because their MSH receptors vary. This means they don't respond to the MSH levels in their blood. 

Hyperpigmentation (darkening of the skin) is a common skin concern in patients with adrenal insufficiency (low levels of adrenal hormones, mainly cortisol).   As a result, the hypothalamus stimulates the pituitary gland to make more hormones that might "boost" the adrenal glands. This hormone can be broken down to make MSH, which causes hyperpigmentation. 

MSH levels are also high during pregnancy and in women who take birth control pills, which can also cause hyperpigmentation. Cushing's syndrome, another endocrine condition, can also lead to hyperpigmentation. 

Questions to Ask Your Healthcare Team

How do doctors test MSH levels? 
I currently see a dermatologist for my skin concerns. Should I be referred to an endocrinologist for a second opinion?

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