Sentence:  On Feb. 12 , 1959 , purified <WSD>corticotropin</WSD> ( ACTH Gel ) , 20 units daily intramuscularly , was started but had to be discontinued 3 weeks later because of excessive fluid retention . 
Meaning of the word marked with <WSD> tags:  a hormone produced by the anterior pituitary gland that stimulates the adrenal cortex