Related Experiment Video
Updated: Jun 7, 2026

Endoscopic Endonasal Trans-sphenoidal Approach: Minimally Invasive Surgery for Pituitary Adenomas
Published on: January 17, 2018
GH response to oral glucose tolerance test: a comparison between patients with acromegaly and other pituitary
E Verrua1, M Filopanti, C L Ronchi
1Department of Medical Sciences, University of Milan, Milan, Italy.
Context:
The cutoff value of nadir GH after an oral glucose tolerance test (OGTT) used to define disease remission in acromegaly is higher than that observed in healthy subjects. However, it is uncertain whether the impaired GH inhibition might be related to subtle abnormalities of GH secretion or to functional and/or anatomical hypothalamic-pituitary disconnection due to tumor per se or treatments.
Objective:
The objective of the study was to evaluate the impact of pituitary disorders other than acromegaly on GH response to OGTT. DESIGN, SUBJECTS, AND METHODS: Thirty-three patients (24 females and nine males, aged 50.1 ± 12.3 yr, 13 operated and two irradiated) with various hypothalamic-pituitary disorders (HPDs), 45 healthy subjects (controls), and 42 cured acromegalic patients matched for sex, age. and body mass index were investigated. All subjects were studied for IGF-I levels and GH levels before and during the OGTT.
Results:
In HPD patients mean postglucose nadir GH levels were 0.11 ± 0.08 μg/liter without any difference between patients treated with neurosurgery and/or radiotherapy and untreated and between patients with and without pituitary stalk alterations and/or hyperprolactinemia. Mean nadir GH values were similar in HPD patients and controls (0.11 ± 0.08 vs. 0.08 ± 0.08 μg/liter, P = 0.23) and lower than those found in cured acromegalic patients (0.18 ± 0.13 μg/liter, P = 0.02), although there was an overlapping in about half of patients.
Conclusions:
Hypothalamic control of glucose-mediated GH suppression is not perturbed in patients with HPD. These data indicate that defective GH suppression to glucose that is found in acromegaly is unlikely to reflect a lack of integrity of hypothalamic function.
More Related Videos
06:59Characterization of Metabolic Status in Nonhuman Primates with the Intravenous Glucose Tolerance Test
Published on: November 13, 2016
08:13Study of In Vivo Glucose Metabolism in High-fat Diet-fed Mice Using Oral Glucose Tolerance Test (OGTT) and Insulin Tolerance Test (ITT)
Published on: January 7, 2018
Related Concept Videos
Hypoglycemia and Glucagon
Hyperglycemia
Glucagon-like Receptor Agonists
GLP-1, when administered in high doses intravenously, triggers insulin secretion, inhibits glucagon release, slows gastric emptying, reduces food intake, and restores normal insulin secretion. However, its rapid inactivation by the...
Oral Hypoglycemic Agents: Glinides
Oral Hypoglycemic Agents: Biguanides and Glitazones
Overview of Carbohydrate Metabolism
Glucose transport into cells is facilitated by a family of transport proteins called GLUT (Glucose Transporters). GLUT4 is the primary glucose transporter for insulin-stimulated glucose...