Letdown reflex. In lactating (breastfeeding) mothers, oxytocin acts at the mammary glands, causing milk to be ‘let down’ into a collecting chamber, from where it can be extracted by compressing the areola and sucking at the nipple. Sucking by the infant at the nipple is relayed by spinal nerves to the hypothalamus. The stimulation causes neurons that make oxytocin to fire action potentials in intermittent bursts; these bursts result in the secretion of pulses of oxytocin from the neurosecretory nerve terminals of the pituitary gland.

5-HTP, along with other L-Tryptophan supplements, have been implicated in the flu-like, potentially fatal Eosinophilic Myalgia Syndrome. This syndrome was initially tied to  impurities - Amino Acids called "Peak E" and "Peak X" - which were present in these products because of poor manufacturing processes by a single major supplier. Some people reject this idea and believe that the syndrome is caused by an excess of tryptophan itself (10, 11).
Toxicity effects of melanotan II from therapeutic and overdose exposures include renal dysfunction, rhabdomyolysis, sympathomimetic overdrive, change in size and pigmentation of pre-existing moles, rapid increase in the number of new moles, associated with causing melanomas, posterior reversible encephalopathy syndrome, refractory priapism, stretching and yawning syndrome, shortness of breath, chest pain, abdominal cramping and pain, dizziness and lethargy.
5-HTP supplements are made using an extract from the seeds of Griffonia simplicifolia,a tree native to Africa (2). 5-HTP very rarely occurs naturally in what we eat, but tryptophan, from which 5-HTP is made in the body, is found in a variety of foods. The richest natural food sources include cheese, poultry, eggs, fish, nuts, soy, and various greens.

Six hours later, the mice were returned to cages with the aggressive mice. The mice that were missing their oxytocin receptors didn't appear to remember the aggressive mice and show any fear. Conversely, when mice with increased numbers of oxytocin receptors were reintroduced to the aggressive mice, they showed an intense fear reaction and avoided the aggressive mice.
If you’re looking for hard proof that taking 5-HTP to lose weight works, we’ve got it: In a University of Rome study, obese women who took 5-HTP began eating between 1,000 to 2,000 fewer calories per day. And even as their caloric intake plummeted to a level that would leave many dieters irritable, serotonin was soothing these ladies — and not one reported hunger or diet crankiness. Further boosting spirits: The supplements quadrupled their weight loss, compared to folks given a placebo pill. “They ate a lot less than they normally would because it was easy for them,” Dr. Bhatia notes. Hearing about such an easy way to lose weight might be enough to inspire you to try the supplement for yourself. So, we went ahead and rounded up everything you need to know to get started.

Injected oxytocin analogues are used to induce labour and support labour in case of non-progression of parturition. It has largely replaced ergotamine as the principal agent to increase uterine tone in acute postpartum haemorrhage. Oxytocin is also used in veterinary medicine to facilitate birth and to increase milk production. The tocolytic agent atosiban (Tractocile®) acts as an antagonist of oxytocin receptors; this drug is registered in many countries to suppress premature labour between 24 and 33 weeks of gestation. It has fewer side-effects than drugs previously used for this purpose (ritodrine, salbutamol and terbutaline).

In the hypothalamus, oxytocin is made in magnocellular neurosecretory cells of the supraoptic and paraventricular nuclei, and is stored in Herring bodies at the axon terminals in the posterior pituitary. It is then released into the blood from the posterior lobe (neurohypophysis) of the pituitary gland. These axons (likely, but dendrites have not been ruled out) have collaterals that innervate neurons in the nucleus accumbens, a brain structure where oxytocin receptors are expressed.[31] The endocrine effects of hormonal oxytocin and the cognitive or behavioral effects of oxytocin neuropeptides are thought to be coordinated through its common release through these collaterals.[31] Oxytocin is also produced by some neurons in the paraventricular nucleus that project to other parts of the brain and to the spinal cord.[32] Depending on the species, oxytocin receptor-expressing cells are located in other areas, including the amygdala and bed nucleus of the stria terminalis.

Jump up ^ Xu J, Jian B, Chu R, Lu Z, Li Q, Dunlop J, Rosenzweig-Lipson S, McGonigle P, Levy RJ, Liang B (December 2002). "Serotonin mechanisms in heart valve disease II: the 5-HT2 receptor and its signaling pathway in aortic valve interstitial cells". The American Journal of Pathology. 161 (6): 2209–18. doi:10.1016/S0002-9440(10)64497-5. PMC 1850896. PMID 12466135.