Melanotan


 * Note: this article describes both melanotan and melanotan II: although their names are similar, they have different chemical and biological properties.

Melanotan 1 and melanotan II are both analogs of the peptide hormone alpha-melanocyte stimulating hormone (&alpha;-MSH) that tend to induce skin tanning. Melanotan II has the additional effect of increasing libido.

Historical development
Both drugs were developed at the University of Arizona. Researchers there knew that one of the best defenses against skin cancer was a natural tan which has been slowly developed over weeks. They hypothesized that an effective way to reduce skin cancer rates in people would be to induce the body's natural tanning system to produce a protective tan prior to UV exposure. They knew the body's naturally occurring hormone alpha-melanocyte stimulating hormone (&alpha;-MSH) caused melanogenesis, a process by which the skin's tanning cells (melanocytes) produce the skin's tanning pigment (melanin). With that knowledge they tested to see if administering this hormone to the body directly could be an effective method to cause sunless tanning. What they found was that while it appeared to work, natural alpha-MSH had too short a half life in the body to be practical as a therapeutic drug. So they decided to find a more potent and stable alternative, one that would be more practical.

After synthesizing and screening hundreds of molecules, the researchers headed by Dr. Victor Hruby, found a peptide that after trials and testing seemed to not only be safe but also approximately 1,000 times more potent than natural &alpha;-MSH. They dubbed this new peptide Melanotan. Since their discovery, numerous studies dating back to the mid-1980s have shown no obvious toxic effects of Melanotan. Because skin cancer (melanoma) today is a major health concern, Melanotan is expected to be used as a drug to combat it. Melanotan will do this by stimulating the body's natural tanning mechanism to create a tan without first needing exposure to harmful levels of UV radiation. This in turn will reduce the potential for skin damage that can eventually lead to skin cancer.

Melanotan 1
Melanotan 1 has the amino acid sequence Ac-Ser-Tyr-Ser-Nle-Glu-His- D -Phe-Arg-Trp-Gly-Lys-Pro-Val-NH 2 or [Nle4, D -Phe7]-alpha-MSH.

Melanotan is currently being tested and developed under the name CUV1647 by the Australian company Clinuvel Pharmaceuticals, for indications such as polymorphous light eruption (PMLE) and actinic keratosis (AK).

Melanotan II
Melanotan II has aphrodisiac properties.

It is a cyclic lactam analog of alpha-MSH with the amino acid sequence Ac-Nle-cyclo[Asp-His- D -Phe-Arg-Trp-Lys]-NH 2.

Bremelanotide
Palatin Technologies of New Jersey has developed another hormone targeted towards sexual dysfunction based upon melanotan II called bremelanotide (formerly called PT-141).

Bremelanotide is a metabolite of melanotan II that lacks the C-terminal amide function. Bremelanotide is currently in clinical trials to treat erectile dysfunction and sexual arousal disorder.