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.
Antiandrogen
Antigonadotropins like estrogens and progestogens were both first introduced in the 1930s. The beneficial effects of androgen deprivation via surgical castration or high-dose estrogen therapy on prostate cancer were discovered in 1941. AR antagonists were first discovered in the early 1960s. The steroidal antiandrogen cyproterone acetate was discovered in 1961 and introduced in 1973 and is often described as the first antiandrogen to have been marketed. However, spironolactone was introduced in 1959, although its antiandrogen effects were not recognized or taken advantage of until later and were originally an unintended off-target action of the drug. In addition to spironolactone, chlormadinone acetate and megestrol acetate are steroidal antiandrogens that are weaker than cyproterone acetate but were also introduced earlier, in the 1960s. Other early steroidal antiandrogens that were developed around this time but were never marketed include benorterone (SKF-7690; 17α-methyl-"B"-nortestosterone), BOMT (Ro 7-2340), cyproterone (SH-80881), and trimethyltrienolone (R-2956).