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.
Testosterone benzoate
Testosterone benzoate, or testosterone 17β-benzoate, also known as androst-4-en-17β-ol-3-one 17β-benzoate, is a synthetic, injected anabolic–androgenic steroid (AAS) and an androgen ester – specifically, the benzoate C17β ester of testosterone – which was never marketed. It is a prodrug of testosterone and, when administered via intramuscular injection, is associated with a long-lasting depot effect and extended duration of action. The drug was first described in 1936 and was the first androgen ester and ester of testosterone to be synthesized.