title: Endocrinology
context: The earliest study of endocrinology began in China.[14] The Chinese were isolating sex and pituitary hormones from human urine and using them for medicinal purposes by 200 BCE.[14] They used many complex methods, such as sublimation of steroid hormones.[14] Another method specified by Chinese texts—the earliest dating to 1110—specified the use of saponin (from the beans of Gleditsia sinensis) to extract hormones, but gypsum (containing calcium sulfate) was also known to have been used.[14]
question: Who first identified the endocrine system?
answers: The earliest study of endocrinology began in China