Leal-Cerro A, Venegas E, Garcia-Pesquera F, Jimenez L M, Astorga R, Casanueva F F, Dieguez C
Department of Endocrinology, Hospital Virgen del Rocio, Sevilla, Spain.
Clin Endocrinol (Oxf). 1998 Jan;48(1):117-21. doi: 10.1046/j.1365-2265.1998.00363.x.
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.
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).
Six female patients with untreated Cushing's disease.
Plasma GH levels were measured by immunoradiometric assay.
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).
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.
