Thursday, April 9, 2015

Synthetic cyclic heptapeptide Melanotan 2(MT2)

Melanotan 2(MT2) is a synthetic cyclic heptapeptide that is mainly used to increase tanning. It stimulates a natural increase in melanin production. Melanin is the main determinant of skin color in humans. Melanin is a brown pigment which causes skin to become darker in appearance when exposed to UV rays. According to scientific study that has been based on animal test subjects, the impetus of Melanotan 2’s overall functionality and mechanics can be tied to the pituitary gland. This pea-sized gland located at the bottom of the hypothalamus at the base of the brain essentially acts as the command center for the endocrine system, as it is chiefly charged with the regulation and control of several system-related functions including those related to growth, metabolism, thyroid gland function, and temperature regulation. Melanotan II’s relationship to the pituitary gland can be drilled down to a hormonal level; specifically, to hormones secreted by the pituitary gland known as melanocortins.

In essence, these particular hormones are responsible for the regulation and control of hair and skin pigmentation in an animal test subject. They achieve this measure of control by expressing melanin. The secretion of melanin is triggered by an animal test subject’s exposure to ultraviolet, or UV, rays. When the secretions are expressed, they are manifested upon the surface of the skin. This process in which this occurs is known as melanogenesis. The secretion acts as a natural means of protection against ultraviolet rays. This component, by extension, acts as a protective measure against a hot of various skin afflictions and ailments that result from prolonged exposure to ultraviolet rays. These rays include various forms of skin cancers. The primary issue with melanogenesis is the fact that the melanocortins that trigger this process has a rapid half-life that only lasts several minutes. Naturally, this means that the secretion’s overall effectiveness as a measure of protection against ultraviolet rays is very limited.

Melanotan II was first synthesized at the University of Arizona when looking at possible ways to treat skin cancer. They hypothesized that an effective way to reduce skin cancer rates in people would be to induce the body's natural pigmentary system to produce a protective tan prior to UV exposure.

Clinical trials have shown that Melanotan 2 safely promotes melanogenesis. This is a process were melanocytes produce melanin. Lighter-skinned people have low base levels of melanogenesis. Exposure to UV-B radiation causes an increased melanogenesis. The purpose of the melanogenesis is to protect the hypodermis, the layer under the skin, from the UV-B light that can damage it. It does this by absorbing all the UV-B light and blocking it from passing the skin layer.

MT2 has also been shown to have aphrodisiac effects. Giuliano F et al. showed MT2 exerting a dose-dependent effect on erections in anesthetized rats. They went on to show MT2 having inducer and facilitator activities on erection depending upon delivery route of the peptide. There are various studies showing similar results in both animals and humans. Wessells H et al. highlighted the positive effect MT2 has on sexual desire and erections in men suffering with erectile dysfunction and various organic risk factors.

Through clinical research it has been shown MT2 has excellent fat burning effects. It was previously thought that it assisted weight loss indirectly due to its appetite-reducing effect. However, it now appears that MT2 has direct fat burning effects. Strader AD et al. is a great example of the direct fat burning effect. They conducted a series of tests including one that shown MT2 treatment led to a general reduction in both visceral and subcutaneous fat tissue in high-fat-fed mice. Choi YH et al. also showed in addition to reducing food intake and inhibiting body weight gain, administration of MT2 reduces fat mass. They concluded this was most likely by accelerated lipid mobilization, but not by apoptosis (cell death).

A very interesting effect MT2 brings about is its ability to increase insulin sensitivity during researchers' trials. Heijboer AC et al studied the effects MT2 has on hepatic and whole-body insulin sensitivity. Results showed administration of MT2 increased insulin-mediated glucose disposal but did not affect the capacity of insulin to suppress EGP. MT2's acute effect on insulin sensitivity was further highlighted during studies done by the Nagoya University Graduate School of Medicine. Banno R et al.  examined the effects MT2 had on insulin sensitivity in diet-induced obese rats. The insulin tolerance test showed that insulin sensitivity was significantly improved in the MT2 group compared to the pair-fed group. Furthermore, MT2 treatment increased the number of small-sized adipocytes in epididymal white adipose tissues, suggesting that MT2 increased insulin sensitivity through action on the white adipose tissues.

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