Prostaglandin was discovered from
Prostaglandins were believed to be pa of the prostatic secretions, and eventually were discovered to be produced by the seminal vesicles. ... The biochemists Sune K. Bergstrom, Bengt I. Samuelsson and John R. Vane jointly received the 1982 Nobel Prize in Physiology or Medicine for their research on prostaglandins. Ref: guyton and hall textbook of medical physiology 12 edition
Tear
Saliva
Seminal fluid
Blood
Endocrinology