The posterior lobe of the pituitary gland in the brain.
The posterior pituitary gland, a.k.a, neurohypophysis. These are the only 2 hormones that are secreted from here.
Oxytocin is secreted by the posterior pituitary and is peptide/water-soluble. It stimulates contractions during childbirth and milk secretion during nursing.
In short, the endocrine system.
MSH- Melanocyte stimulating hormone- is secreted by the intermediate lobe of the pituitary gland.