Sentence:  The importance of knowing in what chemical forms the <WSD>hormone</WSD> may exist is accentuated by the recent observation that there exists an abnormally long-acting TSH in blood drawn from many thyrotoxic patients ( Adams , 1958 ) . 
Meaning of the word marked with <WSD> tags:  the secretion of an endocrine gland that is transmitted by the blood to the tissue on which it has a specific effect