Insulin sensitivity is negatively correlated with the suppression of serum GH level upon oral glucose tolerance test in patients with acromegaly after total removal of pituitary adenoma

Program: Abstracts - Orals, Featured Poster Presentations, and Posters
Session: SUN 88-129-Acromegaly & Prolactinoma
Clinical
Sunday, June 16, 2013: 1:45 PM-3:45 PM
Expo Halls ABC (Moscone Center)

Poster Board SUN-103
Naoki Edo*1, Koji Morita2, Hisanori Suzuki1, Akira Takeshita1, Noriaki Fukuhara1, Hiroshi Nishioka1, Yuji Tanaka3, Shozo Yamada1 and Yasuhiro Takeuchi1
1Toranomon Hosp, Tokyo, Japan, 2Natl Defense Med Coll, Saitama, Japan, 3National Defense Medical College, Tokorozawa, Japan
Nadir GH is usually less than 0.4ng/ml after 75g oral glucose tolerance test (75gOGTT) in healthy subjects. Thereforenew consensus on criteria for cure of acromegaly has been recently proposed (JCEM 95:3141). However, in some acromegaly patients who were considered total tumor removaland no active acromegalic status, nadir GH levels are higher than 0.4ng/ml although their IGF-1 levels are normal for age and sex. Therefore, in order to clarify clinical characteristics of those patients with normal postoperative IGF-1 levels and nadir GH levels between 0.4 and 1.0 ng/ml, we retrospectively collected clinical data of 102 acromegaly patients fulfilling with following conditions; pre-operational HbA1c less than 6.5% and fasting plasma glucose less than 126 mg/dl.We divided these patients into two groups according to their nadir GH levels(group 1(n=10); nadir GH <0.4 ng/ml and group 2(n=92); nadir GH ³a0.4ng/ml upon 75gOGTT examined one year after surgery at Toranomon Hospital between  2007 and  2010. Complete tumor resection was performed in all 102 patients and it was also confirmed on  MRI. We evaluated pre- and post-operative BMI, HOMA-IR and HOMA-β.

  Patients in the group 2 had significantly lower post-operative HOMA-IR (p=0.001) and pre-operative BMIs tended to be lower (p=0.053)than the patients of the Group1. In addition, post-operative HOMA-IR was negatively correlated with nadir GH level (r=-0.269, p=0.006). In contrast, there were no differences in peak glucose levels and other indexes between the two groups.

  It has been reported that negative correlation of insulin resistance with nadir GH level upon the oral glucose tolerance test in healthy subjects. Our study suggests that GH secretion in patients with acromegaly having higher insulin sensitivity is not necessarily suppressed to lower than 0.4 ng/ml upon glucose challenge. Long-term follow-up of patients in the high group in the present study will help to validate the present criteria about biochemical remission of acromegaly.

Nothing to Disclose: NE, KM, HS, AT, NF, HN, YT, SY, YT

*Please take note of The Endocrine Society's News Embargo Policy at http://www.endo-society.org/endo2013/media.cfm