The Ability of β-Cells to Compensate for Insulin Resistance is Restored with a Reduction in Excess Growth Hormone in Korean Acromegalic Patients

Abstract

The aim of this study was to assess the prevalence of diabetes and to study the effects of excess growth hormone (GH) on insulin sensitivity and β-cell function in Korean acromegalic patients. One hundred and eighty-four acromegalic patients were analyzed to assess the prevalence of diabetes, and 52 naïve acromegalic patients were enrolled in order to analyze insulin sensitivity and insulin secretion. Patients underwent a 75 g oral glucose tolerance test with measurements of GH, glucose, insulin, and C-peptide levels. The insulin sensitivity index and β-cell function index were calculated and compared according to glucose status. Changes in the insulin sensitivity index and β-cell function index were evaluated one to two months after surgery. Of the 184 patients, 17.4% were in the normal glucose tolerance (NGT) group, 45.1% were in the pre-diabetic group and 37.5% were in the diabetic group. The insulin sensitivity index (ISI0,120) was significantly higher and the HOMA-IR was lower in the NGT compared to the diabetic group (P = 0.001 and P = 0.037, respectively). The ISI0,120 and disposition index were significantly improved after tumor resection. Our findings suggest that both insulin sensitivity and β-cell function are improved by tumor resection in acromegalic patients.

Impact of Glucose Metabolism Disorders on IGF-1 Levels in Patients with Acromegaly

“…In this study, prediabetes and DM were identified in 41 % and 34 % of the patients and these frequencies are compatible with the previous results reported in the literature [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15]. However frequency of DM was two-fold higher and prediabetes was slightly increased compared to the general Turkish population [30] and in accordance with many studies from several other countries [4-6, 8, 9, 15, 31].…”

“…Therefore, in this study we also evaluated HOMA-β index and pancreatic β-cell dysfunction. HOMA-β levels were lower in prediabetes group compared to patients with NGT, however, there was no statistical significance similar with previous observations in the literature [9]. These results may be interpreted as declining pancreatic β-cell functions in prediabetes patients.…”

“…However, effect of high IGF-1 levels on insulin sensitivity is controversial in patients with acromegaly. There are several studies indicating significantly higher IGF-1 levels are effective in development of IR or DM [5,9,10,14,15,42]. However, it is not certain whether the elevated IGF-1 levels are directly diabetogenic.…”

“…Glucose metabolism disorders such as prediabetes, which is defined as impaired fasting glucose (IFG) or impaired glucose tolerance (IGT), and overt diabetes mellitus (DM) are frequently seen in patients with acromegaly. The frequencies of prediabetes and DM are presented with a wide range of 16-54 % and 19-56 %, respectively [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15]. Several factors such as age, sex, family history, duration of acromegaly, maximum tumor diameter, baseline growth hormone (GH) and insulin-like growth factor 1 (IGF-1) levels, presence of concomitant hypertension, hyperlipidemia, and hyperprolactinemia have been evaluated in a number studies, which reported variable results.…”

Dramatic Improvement of Diabetes Mellitus Following the Treatment of Coexisting Acromegaly and Cushing's Syndrome

“…Growth hormone (GH) and glucocorticoids can block the actions of insulin, resulting in diabetes mellitus (1,4). There have been several studies regarding the mechanism of increased insulin resistance in acromegaly patients.…”