The Glucagon Stimulation Test for Evaluation of Adult Growth Hormone Deficiency and Adrenocorticotropic Axis

Not Applicable

Completed

Conditions: Adult Growth Hormone Deficiency
Hypothalamic-pituitary Disorders

Interventions: Procedure: glucagon stimulation test and insulin tolerance test

Registration Number: NCT01282164

Lead Sponsor: The Cleveland Clinic

Brief Summary: The purpose of this study is to find out if the Glucagon Stimulation Test (GST) is a reliable alternative to the Insulin Tolerance Test (ITT) for diagnosis of Growth Hormone Deficiency (GHD) and adrenal insufficiency. In some patients the accuracy of the GST for evaluation of adrenal insufficiency is compared to the adrenocorticotropin hormone (ACTH ) stimulation test.

Detailed Description: Growth hormone is a protein that is produced by the pituitary gland and influences the metabolism (how fast things work) of other proteins, carbohydrates, and fats in the body. This allows the growth hormone to help humans keep a healthy balance between fat, muscle and bone throughout their life. Some people have what is called Growth Hormone Deficiency (GHD), which means that they do not produce enough growth hormone. GHD may lead to a tendency to be fat, (especially around the abdominal area), a reduced ability to exercise, heart disease, an increased possibility of breaking bones, and a general reduced quality of life.

GHD is usually evaluated through growth hormone stimulation test(s). One of the most reliable tests to evaluate if someone has GHD is by using arginine + Growth Hormone Releasing Hormone (GHRH) test. However, Since 2008 GHRH is no longer available in the USA. For this reason there has been a significant gap for an alternative test for evaluation of patients suspected to have GHD that can be easily performed and be reliable. The Insulin Tolerance Test (ITT) is generally considered the gold standard test for evaluation of growth hormone (GH) deficiency. The ITT involves giving insulin intravenously (through a plastic tube inserted in your vein) to lower your blood sugar followed by the collection of blood samples to evaluate how your body handles low blood sugar. There are side effects of the ITT including hypoglycemia (low blood sugar causing you to become weak, perspire, shaky and have some mental cloudiness) which can be unpleasant. ITT can not be performed in patients older than 65 years of age and in those with certain medical conditions such as history of heart disease, seizure disorder or stroke. At the same time, the ITT needs to be done by an experienced clinician and requires trained staff to perform. For this reason there is a need for an alternative reliable test for evaluation of GHD.

The second purpose of this study is to find out if you have adrenal insufficiency. Cortisol is a hormone produced by the adrenal gland and is released in response to stress. Cortisol production is regulated through the hypothalamus and the pituitary gland. Its primary functions are to increase blood sugar, regulate the immune system and aid in fat, protein and carbohydrate metabolism. Patients with low cortisol may experience fatigue, body ache, sleep disturbance, nausea and mood changes. Pituitary disorders may lead to low cortisol levels and can cause symptoms associated with adrenal insufficiency. The Insulin Tolerance Test (ITT) can also be used for the evaluation of adrenal function. Patients who can not undergo ITT, can be evaluated by the ACTH (adrenocorticotropic hormone) Stimulation Test, which is generally very well tolerated. Preliminary results from previous studies indicate that the Glucagon Stimulation Test (GST) may be used to evaluate adrenal function. The investigators in this study will compare your cortisol levels during two different GSTs with the cortisol levels achieved during ITT or ACTH stimulation test.

Since the 1970s, the Glucagon Stimulation Test (GST) has been used by several research studies for evaluation of GHD and adrenal insufficiency. Glucagon is a hormone produced in the pancreas and is secreted during times of low blood sugar or in response to growth hormone. It is used to raise very low blood sugar and in diagnostic testing of the stomach and other digestive organs. Glucagon is readily available, relatively inexpensive and generally well tolerated; the major side effects include upset stomach that can lead to vomiting and headaches. It can be used in patients with diabetes and those older than 65 years of age.

The glucagon stimulation test (GST) has been suggested as an alternative test to ITT for evaluation of growth hormone deficiency (GHD) and adrenal insufficiency. The test is similar to the ITT and ACTH Stimulation Test in that blood samples are taken both before and after the medication is given. Glucagon is given intramuscularly (as in injection in your muscle). The fewer side effects make this an attractive substitute for the ITT. The 2007 consensus guideline by the GH Research Society considers GST as a test that may be used for evaluation of patients suspected to have GHD. However, the same statement does not provide any diagnostic cut-off value for GH during the GST. The purpose of this study is to see if the GST can be an accurate substitute for the ITT in the evaluation of both GHD and adrenal insufficiency.

Recruitment & Eligibility

Status: COMPLETED

Sex: All

Target Recruitment: 43

Inclusion Criteria

18 to 80 years of age
male and female
hypothalamic pituitary disorders (study subjects)
history of regular, age appropriate menses (control subjects)
male subjects with normal serum testosterone and follicle stimulating hormone (FSH) (control subjects)
normal FSH in post-menopausal subjects (control subjects)
normal thyroid stimulating hormone (TSH), free thyroxine (T4), prolactin (control subjects)

Exclusion Criteria

unable to give consent
pregnancy
active acromegaly
pheochromocytoma
active Cushing's disease
pituitary insult within past 6 weeks
elevated alanine aminotransferase (ALT) or aspartate aminotransferase (AST)
renal failure
history of malignancy
severe acute illness
uncontrolled hypertension
Diabetes mellitus (DM) type 1
Hemoglobin (Hgb) A1c >9% in last 3 months in Type 2 DM
severe coronary artery disease
women <50 years of age with untreated hypogonadism
men with untreated hypogonadism
growth hormone treatment in the past 3 months

Study & Design

Study Type: INTERVENTIONAL

Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
Control	glucagon stimulation test and insulin tolerance test	The control group will consist of healthy volunteers matched to the study group for age, gender, Body mass index (BMI) and estrogen status. Note: Allegheny site is not enrolling in the control group. Control subjects underwent fixed-dose glucagon stimulation test (GST), weight-based GST and insulin tolerance test (ITT).
Study patients	glucagon stimulation test and insulin tolerance test	patients with growth hormone deficiency or hypothalamic-pituitary disorders underwent fixed-dose glucagon stimulation test (GST), weight-based GST and insulin tolerance test (ITT).

Primary Outcome Measures

Name	Time	Method
Peak GH Level in Adult Patients With Hypothalamic-pituitary Disorders and 1-2 Pituitary Hormone Deficiency (PHD).	one year	The peak growth hormone (GH) during Insulin Tolerance Test (ITT), fixed- dose glucagon stimulation test (GST) and weight-based GST in patients with adult onset hypothalamic-pituitary disease and 1-2 pituitary hormone deficiency (PHD) other than growth hormone (GH) deficiency.
Peak Cortisol Level in Healthy Volunteers.	one year	The peak cortisol levels during Insulin Tolerance Test (ITT), fixed- dose glucagon stimulation test (GST) and weight-based GST in healthy volunteers.
Peak Cortisol Level During Adrenocorticotropin Hormone (ACTH) Stimulation Test	one year	The peak cortisol level during ACTH stimulation test in 3 patients with adult onset hypothalamic-pituitary disease who were older than 65 years of age and could not under go insulin tolerance test (ITT).
Peak GH Level in Adult Patients With Hypothalamic-pituitary Disorders and Three or More Pituitary Hormone Deficiency (PHD).	one year	The peak growth hormone (GH) during Insulin Tolerance Test (ITT), fixed- dose glucagon stimulation test (GST) and weight-based GST in patients with adult onset hypothalamic-pituitary disease with three or more pituitary hormone deficiency (PHD) other than growth hormone (GH) deficiency.
Peak Growth Hormone (GH) Level in Healthy Volunteers	one year	The peak growth hormone (GH) during Insulin Tolerance Test (ITT), fixed- dose glucagon stimulation test (GST) and weight-based GST in healthy volunteers
Peak Cortisol Level in Adult Patients With Hypothalamic-pituitary Disorders and 1-2 Pituitary Hormone Deficiency (PHD).	one year	The peak cortisol level during Insulin Tolerance Test (ITT), fixed- dose glucagon stimulation test (GST) and weight-based GST in patients with adult onset hypothalamic-pituitary disease and 1-2 pituitary hormone deficiency (PHD) other than growth hormone (GH) deficiency.
Peak Cortisol Level in Adult Patients With Hypothalamic-pituitary Disorders and Three or More Pituitary Hormone Deficiency (PHD).	one year	The peak cortisol level during Insulin Tolerance Test (ITT), fixed- dose glucagon stimulation test (GST) and weight-based GST in patients with adult onset hypothalamic-pituitary disease and three or more pituitary hormone deficiency (PHD) other than growth hormone (GH) deficiency.

Secondary Outcome Measures

Name	Time	Method

Trial Locations

Locations (4): Allegheny Endocrinology Associates
🇺🇸
Pittsburgh, Pennsylvania, United States
Massachusetts General Hospital
🇺🇸
Boston, Massachusetts, United States
Cleveland Clinic Endocrinology, Diabetes and Metabolism
🇺🇸
Cleveland, Ohio, United States
Oregon Health and Sciences University
🇺🇸
Portland, Oregon, United States