Endocrine Abstracts (2006) 11 P604

Ghrelin test for the assessment of growth hormone (GH) status in successfully treated patients with acromegaly

S Pekic Djurdjevic1, M Doknic1, D Miljic1, M Joksimovic2, J Glodic3, M Djurovic1, C Dieguez4, FF Casanueva5 & V Popovic1

1Institute of Endocrinology, Diabetes and Diseases of Metabolism, University Clinical Center, Belgrade, Yugoslavia; 2Institute of Neurosurgery, University Clinical Center, Belgrade, Yugoslavia; 3Laboratory Consilium, Belgrade, Yugoslavia; 4Department of Physiology, Faculty of Medicine Santiago de Compostela University, Santiago de Compostela, Spain; 5Complejo Hospitalario, Endocrine Section, Santiago de Compostela University, Santiago de Compostela, Spain.

Posttreatment assessment of the disease activity and definition of cure of acromegaly, by measuring GH secretion, remains problematic. Furthermore, with our efforts to achieve tight biochemical control of the disease it is foreseeable that a proportion of patients may be rendered GH deficient (GHD). The aim of our study was to evaluate residual GH secretion in cured patients with acromegaly. The study was approved by the Hospital Ethical Committee and after informed consent, blood samples were obtained. At baseline circulating GH, IGF-I, IGFBP-3 and leptin levels were measured in 32 acromegalic patients nine years after treatment with surgery and few with radiotherapy. Two tests were performed: the oral glucose tolerance test (OGTT) and ghrelin test (1 μg/kg iv bolus) and results were compared with 11 age-, sex- and BMI- matched control subjects. According to the consensus criteria (normal IGF-I levels and post-OGTT GH nadir <1 μg/l), 20 treated acromegalic patients were cured, 6 had discordant IGF-I and GH nadir during OGTT, while 6 had persistent acromegaly. After GH provocative test with ghrelin (cut-off for severe GHD <3 μg/l) we detected 11 severely GHD patients among 20 cured acromegalic patients. Mean GH peak (±S.E.M) response to ghrelin test in GHD acromegalics was significantly lower compared with cured acromegalics with sufficient GH (GHS) secretory capacity (1.6±0.3 μg/l vs 20.1±2.4 μg/l, P<0.01) and control subjects (31.1±2.5 μg/l, P<0.01). Mean IGF-1 and IGFBP-3 levels were not different between GHD and GHS cured acromegalics. Leptin levels and BMI were significantly higher in GHD male acromegalics compared with GHS patients, while in GHD females BMI tended to be higher while leptin levels were not different. In conclusion, the assessment of residual GH secretory capacity is necessary in the long-term follow up of successfully treated acromegalics since a large of proportion of these patients are rendered GH deficient.

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