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.
List of drugs by year of discovery
In 1901 Jokichi Takamine isolated and synthesized the first hormone, Adrenaline. In 1907 Alfred Bertheim synthesized Arsphenamine, the first antibiotic made by men. In 1927 Erik Rotheim patented the first aerosol spray can. In 1933 Robert Pauli Scherer created a method to develop softgels.