Pancreas – an organ of digestion which is inside the abdomen. It makes insulin, which controls the amount of sugar in the bloodstream. It also makes other hormones such as glucagon and somatostatin.
Ovaries – are inside the female pelvis. They make female sex hormones like oestrogen.
Testes – they hang in the male scrotal sack. They make male sex hormones like testosterone.
Other lesser known endocrine organs include:
Adipose tissue (fat tissue) – is recognised to be metabolically important. It releases hormones such as leptin, which affect appetite, and is also a site of oestrogen production. Insulin also acts on adipose tissue.
Kidneys – produce erythropoietin (EPO) which stimulates red blood cell production, produce renin which is needed for blood pressure regulation and produce the active form of Vitamin D (1–25 dihydroxy vitamin D3)
Gut – an increasing number of hormones in the gut are being researched and being understood to effect metabolism and appetite. Included are glucagon-like peptide 1 (GLP–1), ghrelin which stimulates appetite, and somatostatin.