Prothoracicotropic hormone
Prothoracicotropic hormone (PTTH) was the first insect hormone to be discovered. It was originally described simply as "brain hormone" by early workers such as Stefan Kopeć (1922) and Vincent Wigglesworth (1934), who realized that ligation of the head of immature insects could prevent molting or pupation of the body region excluded from the head if the ligation was performed before a critical age in the lifestage was reached. After a certain point the ligation had no effect and both sections of the insect would molt or pupate. However, implantation of a conspecific brain to a sessile ligated abdomen or an abdomen under diapause would induce molting or pupation. Thus, the brain was originally thought to be the source of the hormone that induces molting in insects.
Arthur Riggs (geneticist)
Riggs and Itakura collaborated with Herbert Boyer at Genentech, and used recombinant DNA technology to become the first to produce a human protein in E. coli. Following the advice of Riggs and Itakura, the group successfully produced the hormone Somatostatin in 1977 as a proof of concept before they attempted to work with the more complicated insulin molecule. They were able to link somatostatin to a larger protein, beta-galactosidase, produce it in E. coli, isolate it, and then separate the somatostatin from the galactosidase. Somatostatin was the first mammalian hormone to be produced in a bacterium.