title: Enhanced growth hormone (GH) responsiveness to GH-releasing hormone after dietary restriction in patients with Cushing's syndrome.
abstract: OBJECTIVE
  In patients with Cushing's syndrome, decreased growth hormone (GH) secretion is observed although the basic mechanism is not yet understood. A short-term hypocaloric diet is known to increase both spontaneous and GHRH-stimulated GH secretion in normal subjects. In order to gain further insight into the altered GH secretion in patients with Cushing's syndrome, we assessed the effect of a short-term hypocaloric diet on GH responses to GHRH in these patients.
  
  
  METHODS
  Two GHRH tests (1 microgram/kg i.v.) were performed, the first under basal conditions (normocaloric diet) and the second after a 3-day hypocaloric diet (650 cal/day).
  
  
  METHODS
  Six female patients with untreated Cushing's disease.
  
  
  METHODS
  Plasma GH levels were measured by immunoradiometric assay.
  
  
  RESULTS
  GHRH-induced GH release was impaired in patients with Cushing's disease on a normal diet (mean peak 12.4 +/- 6.4 mU/l, area under the curve (AUC) 744 +/- 332 mU/l/120 min). Following a hypocaloric diet, GH responses to GHRH were markedly enhanced in the same group of patients (mean peak 46.2 +/- 14.8 mU/l, AUC 3142 +/- 1032 mU/l/120 min, P < 0.05).
  
  
  CONCLUSIONS
  This study demonstrates that in patients with Cushing's disease the somatotroph hyporesponsiveness to growth hormone releasing home is improved after a short-term hypocaloric diet. Therefore, blunted growth-hormone secretion in chronic hypercortisolism is a potentially reversible state and the secretory capacity of the somatotroph appears not to be severely compromised in patients with Cushing's disease.
authors.affiliation: Department of Endocrinology, Hospital Virgen del Rocio, Sevilla, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Leal-Cerro
authors.forename: E
authors.initials: E
authors.lastname: Venegas
authors.forename: F
authors.initials: F
authors.lastname: Garcia-Pesquera
authors.forename: L M
authors.initials: LM
authors.lastname: Jimenez
authors.forename: R
authors.initials: R
authors.lastname: Astorga
authors.forename: F F
authors.initials: FF
authors.lastname: Casanueva
authors.forename: C
authors.initials: C
authors.lastname: Dieguez
mesh_terms: D000293:Adolescent; D000324:Adrenocorticotropic Hormone / Q000097:blood; D000328:Adult; D003480:Cushing Syndrome / Q000097:blood / Q000378:metabolism* / Q000652:urine; D004040:Dietary Carbohydrates / Q000008:administration & dosage*; D005260:Female; D013006:Growth Hormone / Q000097:blood / Q000378:metabolism*; D006801:Humans; D006854:Hydrocortisone / Q000097:blood / Q000652:urine; D008875:Middle Aged; D017337:Sermorelin
chemical_list: D004040:Dietary Carbohydrates; D017337:Sermorelin; D000324:Adrenocorticotropic Hormone; D013006:Growth Hormone; D006854:Hydrocortisone