The expression of Tβ4 mRNA is cell cycle dependent and is highest at the G0/G1 transition and during S-phase (), and changes in the expression of Tβ4 appear to be related to cell differentiation. It has been reported that hepatocyte growth factor, nerve growth factor or fibroblast growth factor (FGF) can increase the level of Tβ4 mRNA () and, in addition, interferon treatment augments the transcription of the Tβ4 gene (). It has also been shown that increased Tβ4 expression in cancer cells promotes metastasis, possibly by increasing cell mobility.
The hormone does not act alone. In 2013, neuroscientist Robert Malenka at Stanford University in California and his colleagues showed that oxytocin works together with the neurotransmitter serotonin to reduce the excitability of neurons in the nucleus accumbens9, a brain region involved in reward. This process seems to support the preference of mice to return to environments where they had rewarding social interactions with other animals. “Oxytocin is part of a system,” Carter says, “and it's not the only molecule that matters, but it's one that in some way is regulatory over a large number of other systems.”
In November 2008, the UK Medicines and Healthcare products Regulatory Agency (MHRA) warned the public against melanotan use stating it was an unlicensed medicine that may not be safe. As such, it is illegal to market or supply this product in the UK due to its unlicensed nature. Additionally the MHRA warned 18 companies about selling or advertising the product and closed down 72 websites involving melanotan. By 2013, the MHRA had received 18 reports of 74 separate reactions to the products and reactions have involved stomach and heart problems, as well as blood and eye disorders.
5-HTP is sometimes taken by people coming down from MDMA to relieve post-MDMA dysphoria. As 5-HTP is a necessary precursor for the brain to produce more serotonin, and MDMA use depletes a person's natural serotonin levels, it is believed that taking 5-HTP after consuming MDMA will speed up serotonin production. DanceSafe claims that the anecdotal evidence is widespread and that the theory is physiologically reasonable. Backing up this approach is research conducted by Wang, et al. in 2007, which observed that MDMA-induced depletions of 5-HT (serotonin) were restored in rats after administration 5-HTP, and suggested that this approach might be clinically useful in abstinent MDMA users.