ACTH is a segment of a much larger glycoprotein prohormone molecule called proopiomelanocortin (POMC). POMC is synthesized by the corticotrophs of the anterior pituitary, which constitute about 10 percent of the gland.
Caviar harvested from an older fish is the more rare, and more sought after, white caviar. The Beluga sturgeon are primarily found in the Caspian Sea, which is surrounded by Iran, Azerbaijan, Russia, Kazakhstan and Turkmenistan. The other primary source of Beluga sturgeon is the Black Sea near Russia and Romania.
Traditionally, the term caviar refers only to roe from wild sturgeon in the Caspian Sea and Black Sea (Beluga, Ossetra and Sevruga caviars). Depending on the country, caviar may also be used to describe the roe of other fish such as salmon, steelhead, trout, lumpfish, whitefish, carp, and other species of sturgeon.