title: 24-hour serum concentration profile of cortisol in patients with Cushing's disease.
abstract: To evaluate whether or not patients with Cushing's disease can be differentiated from those with obesity by the determination of 24-hour integrated serum concentrations of cortisol we studied healthy, nonobese males (n = 5), as well as patients with marked obesity (n = 5) and with Cushing's disease (n = 7) in whom diagnosis was established biochemically and subsequently confirmed by surgery. Serum cortisol concentrations in samples collected continuously by a portable blood withdrawal pump during 24 hours (08:00-08:00h) were 6.6 +/- 1.7 micrograms/dl and 8.4 +/- 1.5 micrograms/dl in nonobese and obese individuals, respectively. Patients with Cushing's disease presented a mean cortisol concentration of 21.4 +/- 6.4 micrograms/dl (p vs normal: less than 0.005; vs obesity: less than 0.005). Collecting consecutive samples in 4-h periods the decline of serum cortisol from peak to nadir values was 73 +/- 10% and 57 +/- 23% in normal males and obese subjects, respectively, while a decline of only 22 +/- 8% was seen in patients with Cushing's disease. Three of the patients with Cushing's disease exhibited a circadian rhythm of cortisol albeit on an elevated level. These results may reflect variable stages of autonomy in pituitary ACTH-production and hence a possible criteria for differentation of hypothalamic and pituitary forms of Cushing's disease. In regard to differential diagnosis between Cushing's disease and obesity the 24-hour cortisol profile obtained by multiple sampling did not provide additional information to that obtained by a single sample pooled for 24 hours, which was diagnostic in each case.
authors.affiliation: I. Department of Internal Medicine, University of Vienna/Austria.
authors.forename: K
authors.initials: K
authors.lastname: Pirich
authors.forename: H
authors.initials: H
authors.lastname: Vierhapper
mesh_terms: D000324:Adrenocorticotropic Hormone / Q000097:blood; D000328:Adult; D000368:Aged; D001800:Blood Specimen Collection / Q000379:methods; D002940:Circadian Rhythm; D003480:Cushing Syndrome / Q000097:blood* / Q000175:diagnosis; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000097:blood* / Q000652:urine; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000097:blood / Q000175:diagnosis
chemical_list: D000324:Adrenocorticotropic Hormone; D006854:Hydrocortisone