Growth Hormone Feedback to Insulin-like Growth Factor-I (IGF-1) and Oral Glucose Tolerance Test (OGTT)

2014-08-27 03:21:38 | BioPortfolio


Growth hormone (GH) and Insulin-like growth factor-I (IGF-I) secretion are altered in acromegaly and type 2 Diabetes Mellitis (DM). The secretion of GH is mediated by central hypothalamic hormones (GH Releasing Hormone and somatostatin) as well as peripheral factors providing feedback inhibition (IGF-I and glucose, among others). The purpose of this study is to compare growth hormone suppression after an oral glucose tolerance test (OGTT) to growth hormone suppression after recombinant human IGF-I (rhIGF-I) administration. This study will recruit participants with active acromegaly, type 2 diabetes mellitus, and healthy control subjects. Each participant will undergo a screening evaluation, and three subsequent visits. Each participant will receive a placebo subcutaneous injection, OGTT, and administration of rhIGF-I, on separate visit days. Glucose, insulin, GH, bioactive IGF-I and IGF-I binding proteins will be measured after each intervention. Results will be compared between the three groups. It is predicted that the administration of rhIGF-I will demonstrate GH suppression in all healthy subjects and subjects with type 2DM. Some acromegaly subjects may demonstrate GH suppression in response to IGF-I administration, but not to the degree seen in healthy subjects or type 2 DM. OGTT will demonstrate suppression of GH in normal subjects, and will show attenuated suppression in type 2 DM and a failure of suppression in acromegaly.

Study Design

Masking: Single Blind (Subject)




oral glucose tolerance test, Subcutaneous administration of recombinant human IGF-1


Cedars-Sinai Medical Center Pituitary Center
Los Angeles
United States




Cedars-Sinai Medical Center

Results (where available)

View Results


Published on BioPortfolio: 2014-08-27T03:21:38-0400

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