Disease relevance of Melanotan-II

• AIMS/HYPOTHESIS: The present study was conducted to evaluate the effects of central administration of melanotan II (MTII), a melanocortin-3/4 receptor agonist, on hepatic and whole-body insulin sensitivity, independent of food intake and body weight [1].
• Reduced anorexigenic efficacy of leptin, but not of the melanocortin receptor agonist melanotan-II, predicts diet-induced obesity in rats [2].
• Preformulation studies with melanotan-II: a potential skin cancer chemopreventive peptide [3].
• The present study examined the effects of melanotan-II (MT-II), a cyclic peptide analogue of alpha-melanocyte stimulating hormone on appetitive and consummatory aspects of female sexual behavior, including aspects of sexual proceptivity (solicitations, hops and darts, ear wiggling, pacing) and receptivity (lordosis) [4].
• MTII injection significantly suppressed feeding induced by 24 hr fasting or suckling-induced hyperphagia [5].

Psychiatry related information on Melanotan-II

• PURPOSE: We evaluated the erectogenic properties of a new cyclic alpha-melanocyte-stimulating hormone analogue, Melanotan-II, to treat men with psychogenic erectile dysfunction [6].

High impact information on Melanotan-II

• Next we tested rats for their sensitivity to the melanocortin agonist melanotan II and found that, as for leptin, ADX enhanced the hypophagic response via a glucocorticoid-dependent mechanism [7].
• The results demonstrate that activation of the ERK pathway is necessary for peripheral CCK and central MTII to suppress food intake [8].
• Third-cerebroventricular administration of equi-anorexigenic doses of leptin and of the MC agonist melanotan-II caused comparable increases in plasma ACTH and corticosterone levels and c-Fos-labeling in approximately 70% of paraventricular hypothalamic (PVN) neuronal cell bodies containing CRH [2].
• In the DIO prediction study, anorexigenic efficacy of melanotan-II was not correlated with any parameter linked to DIO but was highly correlated with MC in situ binding (with labeled [Nle(4),D-Phe(7)]alpha-MSH) as well as CRH immunoreactivity in the PVN of DIO rats [2].
• Sequential administration of fourth ventricular MTII and peripheral CCK at doses that alone produced submaximal stimulation of pERK1/2 produced an additive increase [8].

Biological context of Melanotan-II

• Melanotan-II: Investigation of the inducer and facilitator effects on penile erection in anaesthetized rat [9].
• Thus, the present data for the first time demonstrate the effectiveness of the potent alpha-MSH analog melanotan-II in nerve regeneration and neuroprotection [10].
• In addition, central application of the MC3/4-R agonist melanotan-II decreases body fat (increases lipolysis) beyond that accounted for by its ability to decrease food intake [11].
• Furthermore, MTII injected into the fourth ventricle increased and SHU9119 tended to decrease heart rate and body temperature measured telemetrically in freely moving rats [12].
• Cell incubation with ACTH(1-39) or MTII (melanotan II) did not alter ERK1/2 and JNK phosphorylation, while p38 phosphorylation and intracellular cAMP accumulation occurred within minutes [13].

Anatomical context of Melanotan-II

• To investigate the neural pathways involved in the facilitator effect of melanotan-II, we performed acute spinalization (T8 level) and differential selective nerve transections [9].
• Delivered i.v. (0.1, 0.3 and 1 mg/kg) or within the paraventricular nucleus of the hypothalamus (0.1 and 1 microg), melanotan-II exerted a dose-dependent inducer activity on erection by eliciting erectile events and shortening latency of the first erectile event to occur [9].
• The sciatic nerve crush model was used as a paradigm to investigate the neurotrophic properties of melanotan-II [10].
• The potent melanocortin receptor agonist melanotan-II promotes peripheral nerve regeneration and has neuroprotective properties in the rat [10].
• Retroperitoneal white adipose tissue (WAT) mass and epididymal WAT mass were reduced 46.3% and 21.1%, respectively (P<.05), after MTII, but not after PF, compared with the saline control rats [14].

Associations of Melanotan-II with other chemical compounds

• Effects of peripheral administration of melanotan II (MTII), a melanocortin agonist, on insulin sensitivity and glucose tolerance were examined in Otsuka Long-Evans Tokushima Fatty (OLETF) rats [15].

Gene context of Melanotan-II

• The melanocortin agonist Melanotan-II reduces the orexigenic and adipogenic effects of neuropeptide Y (NPY) but does not affect the NPY-driven suppressive effects on the gonadotropic and somatotropic axes in the male rat [16].
• In addition, neither melanotan-II (1.0 nmol, a non-selective MC3/4-R agonist) nor gamma(1)-melanocyte-stimulating hormone (10 nmol, a selective MC3-R agonist) affected significantly GH release in fasted rats [17].
• The use of telemetry technology to test the proerectile effect of melanotan-II (MT-II) in conscious rats [18].
• Two of these analogs, a linear peptide, melanotan I, and a cyclic truncated peptide, melanotan II (MTI and MTII, respectively) have been patented and tested clinically for studies on tanning of the skin (MTI) and for diagnosis and treatment of male erectile dysfunction (MTII) [19].
• When given as an intracerebroventricular bolus injection, Melanotan-II (MT-II), a non selective MC receptor agonist, inhibits feeding, suppresses the NPY orexigenic action, and reduces basal insulinaemia [16].

Analytical, diagnostic and therapeutic context of Melanotan-II

• MATERIALS AND METHODS: Ten men with erectile dysfunction of no known organic cause were entered in a double-blind, placebo controlled crossover study in which the erectogenic properties of Melanotan-II and a vehicle placebo were compared using real-time RigiScan monitoring [6].
• Determination of melanotan-II in rat plasma by liquid chromatography/tandem mass spectrometry: determination of pharmacokinetic parameters in rat following intravenous administration [20].
• A high-performance liquid chromatographic (HPLC) procedure has been developed for the quantification of Melanotan-II (MT-II), a cyclic heptapeptide which promotes rapid tanning of the skin, in rat plasma [21].
• Free fatty acid concentrations in serum were not different between MTII and control groups, but increased by 56.4% in PF group [14].
• Melanotan II (0.025 mg/kg) and vehicle were each administered twice by subcutaneous injection; real-time RigiScan monitoring and a visual analog were used to quantify the erections during a 6-hour period [22].

References