title: Presurgical stress and plasma endorphin levels.
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D004723:Endorphins / Q000097:blood*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D013315:Stress, Psychological / Q000097:blood*; D013514:Surgical Procedures, Operative
chemical_list: D004723:Endorphins