Discordant Nadir GH After Oral Glucose and IGF-I Levels on Treated Acromegaly: Refining the Biochemical Markers of Mild Disease Activity

Autor(es)

Elias, P. C. L. ^[1] ; Lugao, H. B. ^[2] ; Pereira, M. C. ^[2] ; Machado, H. R. ^[2] ; de Castro, M. ^[2] ; Moreira, A. C. ^[2]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Sch Med Ribeirao Preto, Dept Med, Div Neurosurg, BR-14049900 Ribeirao Preto - Brazil

^[2] Univ Sao Paulo, Div Endocrinol, BR-14049900 Ribeirao Preto - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Hormone and Metabolic Research; v. 42, n. 1, p. 50-55, JAN 2010.
• Citações Web of Science: 20

Resumo

Biochemical markers for remission on acromegaly activity are controversial. We studied a subset of treated acromegalic patients with discordant nadir GH levels after oral glucose tolerance test (oGTT) and IGF-I values to refine the current consensus on acromegaly remission. We also compared GH results by two GH immunoassays. From a cohort of 75 treated acromegalic patients, we studied 13 patients who presented an elevated IGF-I despite post-oGTT nadir GH of <= 1 mu g/l. The 12-h daytime GH profile (GH-12 h), nadir GH after oGTT, and basal IGF-I levels were studied in patients and controls. Bland-Altman method showed high concordance between GH assays. Acromegalic patients showed higher mean GH-12 h values (0.71+/-0.36 vs. 0.31+/-0.28 mu g/l; p<0.05) and nadir GH after oGTT (0.48+/-0.32 vs. 0.097+/-0.002 mu g/l; p<0.05) as compared to controls. Nadir GH correlated with mean GH-12 h (r=0.92, p<0.05). The mean GH-12 h value from upper 95% CI of controls (0.54 mu g/l) would correspond to a theoretical normal nadir GH of <= 0.27 mu g/l. Patients with GH nadir <= 0.3 mu g/l had IGF-I between 100-130% ULNR (percentage of upper limit of normal range) and mean GH-12 h of 0.35+/-0.15, and patients with GH nadir >0.3 and <= 1 mu g/l had IGF-I >130% ULNR and mean GH-12 h of 0.93+/-0.24 mu g/l. Our data integrate daytime GH secretion, nadir GH after oGTT, and plasma IGF-I concentrations showing a continuum of mild residual activity in a subgroup of treated acromegaly with nadir GH values <= 1 mu g/l. The degree of increased IGF-I levels and nadir GH after oGTT are correlated with the subtle abnormalities of daytime GH secretion. (AU)

• Processo FAPESP: 07/58365-3 - Fisiopatologia e etiopatogenia molecular de doenças relacionadas aos eixos corticotrófico, somatotrófico e neurohipofisário
• Beneficiário: Margaret de Castro
• Modalidade de apoio: Auxílio à Pesquisa - Temático
• Processo FAPESP: 06/56716-0 - Avaliacao funcional da secrecao do hormonio do crescimento (gh) em pacientes acromegalicos com dissociacao dos niveis de gh e igf-i (insuline - like growth factor-i).
• Beneficiário: Helena Barbosa Lugão
• Modalidade de apoio: Bolsas no Brasil - Iniciação Científica