1
|
Cuboni D, Caputo M, Ghigo E, Aimaretti G, Gasco V. Once upon a time: the glucagon stimulation test in diagnosing adult GH deficiency. J Endocrinol Invest 2024; 47:1621-1631. [PMID: 38461479 PMCID: PMC11196325 DOI: 10.1007/s40618-024-02322-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Accepted: 01/26/2024] [Indexed: 03/12/2024]
Abstract
PURPOSE The clinical features of adult GH deficiency (GHD) are nonspecific, and its diagnosis is established through GH stimulation testing, which is often complex, expensive, time-consuming and may be associated with adverse side effects. Moreover, diagnosing adult GHD can be challenging due to the influence of age, gender, and body mass index on GH peak at each test. The insulin tolerance test (ITT), GHRH + arginine test, glucagon stimulation test (GST), and, more recently, testing with macimorelin are all recognized as useful in diagnosing adult GHD. To date GST is still little used, but due to the unavailability of the GHRH all over the world and the high cost of macimorelin, in the next future it will probably become the most widely used test when ITT is contraindicated. The aim of the present review is to describe the current knowledge on GST. METHODS Narrative review. RESULTS In the last years several studies have suggested some changes in the original GST protocol and have questioned its diagnostic accuracy when the classic GH cut-point of 3 μg/L is used, suggesting to use a lower GH cut-point to improve its sensitivity and specificity in overweight/obese patients and in those with lower pretest GHD probability. CONCLUSION This document provides an update on the utility of GST, summarizes how to perform the test, shows which cut-points should be used in interpreting the results, and discusses its drawbacks and caveats referring to the most recent studies.
Collapse
Affiliation(s)
- D Cuboni
- Division of Endocrinology, Diabetes and Metabolism, Department of Medical Science, ASOU "Città della Salute e Della Scienza" di Torino, University of Turin, C.So Dogliotti 14, 10126, Turin, Italy
| | - M Caputo
- Department of Health Sciences, Università del Piemonte Orientale, Novara, Italy
- Endocrinology, Department of Translational Medicine, Università del Piemonte Orientale, Novara, Italy
| | - E Ghigo
- Division of Endocrinology, Diabetes and Metabolism, Department of Medical Science, ASOU "Città della Salute e Della Scienza" di Torino, University of Turin, C.So Dogliotti 14, 10126, Turin, Italy
| | - G Aimaretti
- Endocrinology, Department of Translational Medicine, Università del Piemonte Orientale, Novara, Italy
| | - V Gasco
- Division of Endocrinology, Diabetes and Metabolism, Department of Medical Science, ASOU "Città della Salute e Della Scienza" di Torino, University of Turin, C.So Dogliotti 14, 10126, Turin, Italy.
| |
Collapse
|
2
|
Ach T, Abdelkrim AB, Hasni Y, Saad G, Kacem M, Chaieb M, Zaouali M, Maaroufi A, Ach K. Safety assessment and potential risks of the glucagon stimulation test in the diagnosis of secondary adrenal insufficiency. Curr Drug Saf 2021; 17:59-63. [PMID: 34315384 DOI: 10.2174/1574886316666210727152000] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Revised: 04/29/2021] [Accepted: 05/07/2021] [Indexed: 11/22/2022]
Abstract
BACKGROUND Although it takes more time, the glucagon stimulation test (GST) is a reliable measure for assessing growth hormone (GH) and adrenocorticotropic hormone (ACTH) secretion. The GST is considered to be a safe test, however, it still has mild side effects and potential risks. OBJECTIVE The objective of this study was to analyze the side effects of the GST while testing adrenal insufficient patients. METHODS This was a prospective study in which GST was performed in eighty-one patients (44 men, 37 women, mean age: 35.83±19.62 years) with pituitary disorder. The GST consisted in an intramuscular injection of 1 mg of glucagon. Blood samples were collected at baseline, and 30, 60, 90, 120, 150, 180 and 210 min after glucagon injection for cortisol measurements. All patients were asked to report side-effects associated with this test. RESULTS The mean peak blood glucose level under GST was 9.01±2.03 mmol/L and the mean glycemic nadir was 4.34±1.75 mmol/L was found most frequently during the 30th minute (p <10-3). During the test, 35 subjects (43.2%) had side effects with a mean age of 42.89 ± 19.75 years. Frequent side effects included: nausea (29.62%), vomiting (27.16%), abdominal cramps (18.51%) and hunger (13.58%). All patients tolerated the test until the end. Adverse effects were significantly more prevalent in patients older than 50 years (p=0.012). CONCLUSIONS The GST is a reliable alternative to assess hypothalamic pituitary adrenal axis but should be cautiously used especially in the elderly although its minor side effects.
Collapse
Affiliation(s)
- Taieb Ach
- University Hospital of Farhat Hached Sousse, Endocrinology, Tunisia
| | | | - Yosra Hasni
- University Hospital of Farhat Hached Sousse, Endocrinology, Tunisia
| | - Ghada Saad
- University Hospital of Farhat Hached Sousse, Endocrinology, Tunisia
| | - Maha Kacem
- University Hospital of Farhat Hached Sousse, Endocrinology, Tunisia
| | - Molka Chaieb
- University Hospital of Farhat Hached Sousse, Endocrinology, Tunisia
| | - Monia Zaouali
- University Hospital of Farhat Hached Sousse, Hormonal Physiology, Tunisia
| | - Amel Maaroufi
- University Hospital of Farhat Hached Sousse, Endocrinology, Tunisia
| | - Koussay Ach
- University Hospital of Farhat Hached Sousse, Endocrinology, Tunisia
| |
Collapse
|
3
|
Kamoun C, Hawkes CP, Grimberg A. Provocative growth hormone testing in children: how did we get here and where do we go now? J Pediatr Endocrinol Metab 2021; 34:679-696. [PMID: 33838090 PMCID: PMC8165022 DOI: 10.1515/jpem-2021-0045] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Accepted: 03/08/2021] [Indexed: 12/19/2022]
Abstract
OBJECTIVES Provocative growth hormone (GH) tests are widely used for diagnosing pediatric GH deficiency (GHD). A thorough understanding of the evidence behind commonly used interpretations and the limitations of these tests is important for improving clinical practice. CONTENT To place current practice into a historical context, the supporting evidence behind the use of provocative GH tests is presented. By reviewing GH measurement techniques and examining the early data supporting the most common tests and later studies that compared provocative agents to establish reference ranges, the low sensitivity and specificity of these tests become readily apparent. Studies that assess the effects of patient factors, such as obesity and sex steroids, on GH testing further bring the appropriateness of commonly used cutoffs for diagnosing GHD into question. SUMMARY AND OUTLOOK Despite the widely recognized poor performance of provocative GH tests in distinguishing GH sufficiency from deficiency, limited progress has been made in improving them. New diagnostic modalities are needed, but until they become available, clinicians can improve the clinical application of provocative GH tests by taking into account the multiple factors that influence their results.
Collapse
Affiliation(s)
- Camilia Kamoun
- Division of Endocrinology and Diabetes, Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Colin Patrick Hawkes
- Division of Endocrinology and Diabetes, Children's Hospital of Philadelphia, Philadelphia, PA, USA.,Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Adda Grimberg
- Division of Endocrinology and Diabetes, Children's Hospital of Philadelphia, Philadelphia, PA, USA.,Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| |
Collapse
|
4
|
Casamitjana L, Giménez-Palop O, Corripio R, Pareja R, Berlanga E, Rigla M, Oliva JC, Caixàs A. Glucagon stimulation test to assess growth hormone status in Prader-Willi syndrome. J Endocrinol Invest 2021; 44:621-629. [PMID: 32720093 PMCID: PMC7878226 DOI: 10.1007/s40618-020-01367-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Accepted: 07/16/2020] [Indexed: 11/24/2022]
Abstract
PURPOSE Growth hormone deficiency (GHD) must be confirmed before starting treatment in adults with Prader-Willi syndrome (PWS). Most studies use the growth-hormone-releasing hormone plus arginine (GHRH-arginine) test. No data are available on the glucagon stimulation test (GST) in PWS. We compared the utility of fixed-dose (1 mg) GST versus GHRH-arginine test in diagnosing GHD. METHODS Adults and late adolescents with PWS underwent both tests on separate days. In the GHRH-arginine test, GHD was defined according to body mass index. In the GST, two cutoffs were analyzed: peak GH concentration < 3 ng/mL and < 1 ng/mL. For analyses, patients were divided into two groups according to body weight (≤ 90 kg and > 90 kg). RESULTS We analyzed 34 patients: 22 weighing ≤ 90 kg and 12 weighing > 90 kg. In patients weighing ≤ 90 kg, the two tests were concordant in 16 (72.72%) patients (k = 0.476, p = 0.009 with GST cutoff < 3 ng/mL, and k = 0.450, p = 0.035 with GST cutoff < 1 ng/mL). In patients weighing > 90 kg, the two tests were not concordant with GST cutoff < 3 ng/mL, but were concordant in 11 (91.6%) patients (k = 0.833, p = 0.003) with GST cutoff < 1 ng/mL. GH peaks on the two tests correlated (r = 0.725, p = 0.008). CONCLUSION Fixed-dose (1 mg) GST using a peak GH cutoff of < 3 ng/mL or < 1 ng/mL promises to be useful for screening for GHD in adults and late adolescents with PWS. However, in those weighing > 90 kg, the < 1 ng/mL cutoff seems better. Larger studies are necessary to establish definitive glucagon doses and cutoffs, especially in extremely obese patients.
Collapse
Affiliation(s)
- L Casamitjana
- Endocrinology and Nutrition Department, Hospital Universitari Parc Taulí, C/ Parc Taulí, 1, 08208, Sabadell, Spain
- Medicine Department, Universitat Autònoma de Barcelona, Bellaterra, Spain
- Institut d'Investigació i Innovació Parc Taulí (I3PT), Sabadell, Spain
| | - O Giménez-Palop
- Endocrinology and Nutrition Department, Hospital Universitari Parc Taulí, C/ Parc Taulí, 1, 08208, Sabadell, Spain
- Medicine Department, Universitat Autònoma de Barcelona, Bellaterra, Spain
- Institut d'Investigació i Innovació Parc Taulí (I3PT), Sabadell, Spain
| | - R Corripio
- Medicine Department, Universitat Autònoma de Barcelona, Bellaterra, Spain
- Institut d'Investigació i Innovació Parc Taulí (I3PT), Sabadell, Spain
- Pediatrics Department, Hospital Universitari Parc Taulí, Sabadell, Spain
| | - R Pareja
- Endocrinology and Nutrition Department, Hospital Universitari Parc Taulí, C/ Parc Taulí, 1, 08208, Sabadell, Spain
- Institut d'Investigació i Innovació Parc Taulí (I3PT), Sabadell, Spain
| | - E Berlanga
- Institut d'Investigació i Innovació Parc Taulí (I3PT), Sabadell, Spain
- Clinical Laboratory Department, UDIAT, Corporació Sanitària Universitària Parc Taulí, Sabadell, Spain
| | - M Rigla
- Endocrinology and Nutrition Department, Hospital Universitari Parc Taulí, C/ Parc Taulí, 1, 08208, Sabadell, Spain
- Medicine Department, Universitat Autònoma de Barcelona, Bellaterra, Spain
- Institut d'Investigació i Innovació Parc Taulí (I3PT), Sabadell, Spain
| | - J C Oliva
- Institut d'Investigació i Innovació Parc Taulí (I3PT), Sabadell, Spain
- Epidemiology Department, Fundació Parc Taulí, Sabadell, Spain
| | - A Caixàs
- Endocrinology and Nutrition Department, Hospital Universitari Parc Taulí, C/ Parc Taulí, 1, 08208, Sabadell, Spain.
- Medicine Department, Universitat Autònoma de Barcelona, Bellaterra, Spain.
- Institut d'Investigació i Innovació Parc Taulí (I3PT), Sabadell, Spain.
| |
Collapse
|
5
|
Vitebskaya AV, Pisareva EA, Popovich AV. [Comparative study of glucagon and insulin tests for diagnostics of secondary adrenal insufficiency and growth hormone deficiency in children and adolescents]. ACTA ACUST UNITED AC 2020; 66:50-58. [PMID: 33481367 DOI: 10.14341/probl12528] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2020] [Accepted: 12/10/2020] [Indexed: 11/06/2022]
Abstract
BACKGROUND Diagnostics of growth hormone deficiency (GHD) and secondary adrenal insufficiency (SAI) is based on estimation of peak GH and cortisol concentrations in provocation tests. Russian consensus on diagnostics and treatment of hypopituitarism in children and adolescences recommends to measure GH and cortisol concentrations in every time-point of insulin test (IT). Glucagon test (GT) is discussed in literature as alternative to IT. AIMS To estimate the possibility to use provocation GT for diagnostics of SAI and GHD in children and adolescents. MATERIALS AND METHODS We investigated blood and urine cortisol levels, IT, and GT in 20 patients 6.5-17.8 years (Me 13.0 (10.4; 15.3)) after surgery and/or radiology and/or chemical therapy of head and neck tumors; remission for 0.4-7.5 years (Ме 2.1 (1.5; 5.2)). RESULTS With cut-off point 550 nmol/L sensitivity and specifity of IT was 100% and 60%, GT - 100% and 53% respectively. Minimal cortisol cut-off level for GT with sensitivity 100% was 500 nmol/L, maximal with specifity 100% - 400 nmol/L.Early morning cortisol levels did not exceed 250 nmol/l in 2 patients with SAI; and were above 500 nmol/l in 8 patients without SAI while primary or repeated examination.GHD was reviled by IT in all patients. Maximal GH concentrations in GT and IT did not differ significantly (p>0.05) but GT results of 4 patients exceeded or met cut-off for this test (7 ng/ml).GT was characterized by less severity compared with IT. CONCLUSIONS For diagnostics of SAI by GT we can advise cut-off points of cortisol level 500 (sensitivity 100%, specifty 53%) and 400 nmol/L (sensitivity 80%, specifity 100%). Measuring of cortisol levels in 2-3 early morning blood samples allows to exclude or to suspect SAI in half of patients before tests. GH peaks in GT can exceed similarly data in IT that needs future investigation.
Collapse
Affiliation(s)
- A V Vitebskaya
- I.M. Sechenov First Moscow State Medical University (Sechenov University)
| | - E A Pisareva
- I.M. Sechenov First Moscow State Medical University (Sechenov University)
| | - A V Popovich
- I.M. Sechenov First Moscow State Medical University (Sechenov University)
| |
Collapse
|
6
|
Maliachova O, Dimitriadou M, Triantafyllou P, Slavakis A, Christoforidis A. Cortisol Levels in Glucagon Stimulation Test in Children Assessed for Short Stature: Clinical and Laboratorial Correlations. Horm Metab Res 2019; 51:798-804. [PMID: 31745940 DOI: 10.1055/a-1036-6396] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
To assess total cortisol levels in children being evaluating for short stature with normal cortisol reserve and to correlate this response to clinical and laboratory data. Children assessed with glucagon test in our department were recruited in this study retrospectively. Inclusion criteria were: i) age>1 year, ii) absence of chronic illness or medication interfering with ACTH-cortisol axis, iii) GH stimulation levels>3ng/mL at least in one provocation test (glucagon or clonidine), iv) absence of multiple pituitary growth hormone deficiencies, v) normal short Synacthen test in cases of low cortisol response in glucagon test.Two hundred and thirty-seven subjects (160 males, 67.5%) with a mean age of 9.02±3.19 years, were finally included in the analysis. Cortisol peak levels but not cortisol AUC were significantly increased in females compared to males (26.83±7.31 μg/dl vs. 24.04±7.20 μg/dl). When linear correlations were studied, both cortisol peak levels and cortisol AUC were linearly but inversely correlated to age (r=-0.234, p<0.001 and r=-0.315, p<0.001, respectively). Finally, cortisol AUC was inversely correlated to weight Z-scores (r=-0.160, p=0.014). When our analysis was limited only to subjects with intact GH response (GH peak> 7 ng/mL), age was still inversely correlated to cortisol AUC (r=-0.312, p<0.001), and cortisol AUC was linearly correlated to GH AUC assessed with clonidine test (r=0.223, p=0.013). Girls, younger and thinner children exhibit higher cortisol response to glucagon test.
Collapse
Affiliation(s)
- Olga Maliachova
- 1st Department of Pediatrics, School of Medicine, Faculty of Health Science, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Meropi Dimitriadou
- 1st Department of Pediatrics, School of Medicine, Faculty of Health Science, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Panagiota Triantafyllou
- 1st Department of Pediatrics, School of Medicine, Faculty of Health Science, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Aris Slavakis
- Hormone Assay Laboratory, Department of Biochemistry, Ippokration General Hospital, Thessaloniki, Greece
| | - Athanasios Christoforidis
- 1st Department of Pediatrics, School of Medicine, Faculty of Health Science, Aristotle University of Thessaloniki, Thessaloniki, Greece
| |
Collapse
|
7
|
Ach T, Yosra H, Jihen M, Abdelkarim Asma B, Maha K, Molka C, Rouatbi S, Monia Z, Ach K. Cortisol cut-points for the glucagon stimulation test in the evaluation of hypothalamic pituitary adrenal axis. Endocr J 2018; 65:935-942. [PMID: 29952338 DOI: 10.1507/endocrj.ej18-0147] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Diagnosis of adrenal insufficiency requires evaluation by dynamic stimulation tests. The insulin tolerance test (ITT) is accepted as the gold-standard test for the evaluation of hypothalamo-pituitary-adrenal (HPA) axis but the test is unpleasant and dangerous. Although it takes more time, glucagon stimulation test (GST) is a good alternative to ITT. The primary aim of this study was to compare the ITT and GSTs in the evaluation of HPA axe in patients with pituitary disorders. We conducted a prospective study in which ITT and GST were performed within 7 days in 81 patients. Serum cortisol was measured. We divided our population in Group 1 (G1): Adrenal Insufficiency (Peak cortisol under ITT <200 ng/mL) and Group 2 (G2): normal response (Peak cortisol under ITT >200 ng/mL). Receiver-operating characteristic (ROC) analysis was performed to identify the thresholds for GST. The mean peak of cortisol under GST was not significantly different from that obtained after ITT in the whole cohort (182.67 ± 89.07 ng/mL vs. 179.75 ± 79.01 ng/mL), and it was significantly reduced in patients of G1 (p < 10-3). ROC curve analysis showed that the best diagnostic accuracy was obtained with a peak cortisol cut-off to GST of 167 ng/mL (sensitivity, 89%; specificity, 79%). Using this cut-off, 86.4% of the patients were correctly classified. In our prospective series, GST is a potential accurate and safe alternative test for the assessment HPA. Test-specific cut-offs should be applied to avoid misinterpretation.
Collapse
Affiliation(s)
- Taieb Ach
- Department of Endocrinology and Diabetology, University Hospital of Farhat Hached, Sousse, Tunisia
| | - Hasni Yosra
- Department of Endocrinology and Diabetology, University Hospital of Farhat Hached, Sousse, Tunisia
| | - Maatoug Jihen
- Department of Epidemiology, University Hospital of Farhat Hached, Sousse, Tunisia
| | - Ben Abdelkarim Asma
- Department of Endocrinology and Diabetology, University Hospital of Farhat Hached, Sousse, Tunisia
| | - Kacem Maha
- Department of Endocrinology and Diabetology, University Hospital of Farhat Hached, Sousse, Tunisia
| | - Chaieb Molka
- Department of Endocrinology and Diabetology, University Hospital of Farhat Hached, Sousse, Tunisia
| | - Sonia Rouatbi
- Department of Physiology, University Hospital of Farhat Hached, Sousse, Tunisia
| | - Zaouali Monia
- Department of Physiology, University Hospital of Farhat Hached, Sousse, Tunisia
| | - Koussay Ach
- Department of Endocrinology and Diabetology, University Hospital of Farhat Hached, Sousse, Tunisia
| |
Collapse
|
8
|
Affiliation(s)
- Cesar L Boguszewski
- Department of Internal Medicine, Endocrine Division (SEMPR), Federal University of Parana, Avenida Agostinho Leao Junior 285, Curitiba, PR, 80030-110, Brazil.
| |
Collapse
|
9
|
Wilson JR, Utz AL, Devin JK. Effects of gender, body weight, and blood glucose dynamics on the growth hormone response to the glucagon stimulation test in patients with pituitary disease. Growth Horm IGF Res 2016; 26:24-31. [PMID: 26774402 PMCID: PMC4716555 DOI: 10.1016/j.ghir.2015.12.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Revised: 11/24/2015] [Accepted: 12/05/2015] [Indexed: 01/13/2023]
Abstract
OBJECTIVE Body weight blunts the growth hormone (GH) response to provocative stimuli. The appropriate GH cut-off to confirm GH deficiency in obese and overweight patients undergoing the glucagon stimulation test (GST) has recently been questioned. We hypothesized that the peak GH would be inversely related to the nadir blood glucose (BG) after glucagon and that this may be a mechanism influencing peak GH in overweight patients. This retrospective study examined effects of gender, body weight, and BG dynamics on GH response to GST in patients evaluated in our Pituitary Center. DESIGN Adult patients who underwent GST from September 2009-2014 were included. Continuous variable comparisons were analyzed using the Mann-Whitney U-test and categorical data by Fisher's Exact Test. Spearman correlation was used to determine associations between continuous variables. RESULTS 42 patients (N=28, 66.7% female) had sufficient data for analysis. Obese patients (N=26) had a reduced GH response, summarized as GH area under the curve (AUC) (p=0.03 vs. non-obese patients) and higher BG during GST, summarized as AUC (p<0.01 vs. non-obese patients). Obese women (N=19), in particular, stimulated lower (p=0.03 vs. non-obese women) and had a higher nadir BG (p=0.03 vs. non-obese women). While weight correlated with extent (rs=0.35; p=0.02) and timing (rs=0.31; p=0.05) of nadir BG reached, there was no significant correlation between BG dynamics and the GH response in the total population (N=42). Ten patients (7 with pan anterior hypopituitarism, defined as 3 anterior pituitary deficiencies) had a peak GH≤0.1ng/mL during GST. When these subjects with a negligible peak GH response were excluded from the analysis, weight was associated with GH AUC (rs=-0.45; p=0.01), peak GH response (rs=-0.42; p=0.02) and nadir BG (rs=0.48; p<0.01). Furthermore, the nadir BG achieved during GST was inversely related to GH AUC (rs=-0.38; p=0.03) and peak GH (rs=-0.37; p=0.04) such that patients (N=32) with higher nadir BG had lower peak GH in response to glucagon. CONCLUSIONS Obese patients, particularly women, do not respond as robustly to glucagon stimulation. These data suggest that there exists an altered BG profile during GST in obese individuals, and that a less robust hypoglycemic stimulus may contribute to an impaired GH response. We suggest measuring BG levels during glucagon stimulation testing to assist with clinical interpretation of GH dynamics. The diagnostic accuracy of the GST in patients with known disorders in glucose metabolism and those taking anti-diabetic medications deserves further study.
Collapse
Affiliation(s)
- Jessica R Wilson
- Division of Diabetes, Endocrinology and Metabolism, Vanderbilt University Medical Center, Nashville, TN, United States.
| | - Andrea L Utz
- Division of Diabetes, Endocrinology and Metabolism, Vanderbilt University Medical Center, Nashville, TN, United States.
| | - Jessica K Devin
- Division of Diabetes, Endocrinology and Metabolism, Vanderbilt University Medical Center, Nashville, TN, United States.
| |
Collapse
|
10
|
Hawkes CP, Grimberg A, Dzata VE, De Leon DD. Adding Glucagon-Stimulated GH Testing to the Diagnostic Fast Increases the Detection of GH-Sufficient Children. Horm Res Paediatr 2016; 85:265-72. [PMID: 26982479 PMCID: PMC4865421 DOI: 10.1159/000444678] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Accepted: 02/12/2016] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND/AIMS The evaluation of children with unexplained hypoglycemia may include a diagnostic fast. However, low growth hormone (GH) concentration during hypoglycemia is not specific to GH deficiency (GHD). The aim of this study was to determine if serial GH measurement following glucagon administration, in the setting of a diagnostic fast, would increase the number of children identified as not having GHD. METHODS We conducted a retrospective chart review of children who had serial GH measurements performed after glucagon administration at the end of a diagnostic fast. Glucagon was administered at the end of the fasting study, and GH was measured every 30 min for 210 min. RESULTS Of the 29 children in this series, only 3 (10%) had GH concentrations >7 ng/ml at the end of the fast, which increased by 16 (55%) after serial GH testing. The percentages of samples with GH concentrations >7 ng/ml were: 10% at baseline, and 25, 39, 41, 41, 33, 43, and 0% every 30 min thereafter. CONCLUSION Additional GH measurements after glucagon administration following a diagnostic fast can improve the identification of children without GHD and thereby save them unnecessary GH stimulation testing and potential GH treatment.
Collapse
Affiliation(s)
- Colin P Hawkes
- Division of Endocrinology and Diabetes, The Children’s Hospital of Philadelphia, Philadelphia, PA, USA,Department of Paediatrics and Child Health, University College Cork, Ireland,National Children’s Research Centre, Dublin, Ireland
| | - Adda Grimberg
- Division of Endocrinology and Diabetes, The Children’s Hospital of Philadelphia, Philadelphia, PA, USA,Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Vivian E Dzata
- Division of Endocrinology and Diabetes, The Children’s Hospital of Philadelphia, Philadelphia, PA, USA
| | - Diva D De Leon
- Division of Endocrinology and Diabetes, The Children’s Hospital of Philadelphia, Philadelphia, PA, USA,Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| |
Collapse
|
11
|
Yuen KCJ, Biller BMK, Katznelson L, Rhoads SA, Gurel MH, Chu O, Corazzini V, Spiller K, Gordon MB, Salvatori R, Cook DM. Clinical characteristics, timing of peak responses and safety aspects of two dosing regimens of the glucagon stimulation test in evaluating growth hormone and cortisol secretion in adults. Pituitary 2013; 16:220-30. [PMID: 22806554 DOI: 10.1007/s11102-012-0407-7] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Weight-based (WB: 0.03 mg/kg) and fixed dose (FD: 1-1.5 mg) regimens of the glucagon stimulation test (GST) have been used to evaluate GH and cortisol secretion in children and adults, respectively. However, experience of the WB regimen in assessing GH and cortisol secretion in adults are limited. We describe a multicenter experience using WB and FD regimens in evaluating GH and cortisol secretion in adults suspected of GH deficiency and central adrenal insufficiency. Retrospective case series of GSTs (n = 515) performed at five tertiary centers. Peak and nadir glucose, and peak GH and peak cortisol responses occurred later with WB (mean dose: 2.77 mg) compared to FD (mean dose: 1.20 mg) regimens. Main side-effects were nausea and vomiting, particularly in younger females. Nausea was comparable but vomiting was more frequent in the WB regimen (WB: 10.0 % vs FD: 2.4 %; P < 0.05). Peak and nadir glucose, ΔGH, and peak and Δcortisol were higher in the WB regimen. In both regimens, age correlated negatively with peak cortisol levels, and body mass index (BMI), fasting, peak and nadir glucose correlated negatively with peak GH levels. WB and FD regimens can induce adult GH and cortisol secretion, but peak responses occur later in the WB regimen. Both regimens are relatively safe, and vomiting was more prevalent in the WB regimen. As age, BMI, and glucose tolerance negatively correlated with peak GH and cortisol levels, the WB regimen may be more effective than the FD regimen in older overweight glucose intolerant patients.
Collapse
Affiliation(s)
- Kevin C J Yuen
- Division of Endocrinology, Diabetes and Clinical Nutrition, Department of Medicine, Oregon Health and Science University, 3181 SW Sam Jackson Park Road, Mailcode: L607, Portland, OR 97239, USA.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
12
|
Kargi AY, Merriam GR. Testing for growth hormone deficiency in adults: doing without growth hormone-releasing hormone. Curr Opin Endocrinol Diabetes Obes 2012; 19:300-5. [PMID: 22596248 DOI: 10.1097/med.0b013e32835430da] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE OF REVIEW This article summarizes recent advances in testing for growth hormone deficiency (GHD) in adults, focusing on critical appraisal of existing growth hormone (GH) provocative tests as well as newer tests in development. RECENT FINDINGS The diagnosis of GHD can be challenging and often requires the use of GH provocative testing. The most widely validated of these is insulin-induced hypoglycemia (ITT), which requires close supervision and has significant contraindications and side-effects. The arginine-growth hormone-releasing hormone (GHRH) test had become widely used as a safe and accurate alternative to the ITT, but GHRH is currently unavailable for clinical use in the USA. On the basis of review of recent literature we recommend that in the absence of GHRH, glucagon stimulation testing should be the preferred alternative to ITT. Several synthetic GH secretagogues that mimic the gastric peptide ghrelin are currently in development and may become available for use in the diagnosis of GHD in the near future. Other GH provocative tests suitable for use in children lack adequate specificity for the diagnosis of GHD in adults. SUMMARY Due to the current unavailability of the arginine-GHRH test in the USA, when ITT is contraindicated or impractical we recommend the glucagon stimulation testing as the GH provocative test of choice. There remains a need for a simple, safe and accurate test for the diagnosis of GHD.
Collapse
Affiliation(s)
- Atil Y Kargi
- Division of Endocrinology, Diabetes, and Metabolism, University of Miami Miller School of Medicine, Miami, Florida, USA
| | | |
Collapse
|
13
|
Iranmanesh A, Lawson D, Veldhuis JD. Distinct metabolic surrogates predict basal and rebound GH secretion after glucose ingestion in men. J Clin Endocrinol Metab 2012; 97:2172-9. [PMID: 22472562 PMCID: PMC3387415 DOI: 10.1210/jc.2011-3317] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
CONTEXT GH secretion declines rapidly after glucose ingestion and then recovers to higher-than-baseline levels (rebound GH release). HYPOTHESIS Selective metabolic markers predict the magnitude of glucose-suppressed GH release and postglucose rebound-like GH secretion. DESIGN Prospectively randomized crossover study of GH secretion after glucose vs. water ingestion. SETTING The study was conducted at a clinical translational research center. PARTICIPANTS Sixty-nine healthy men aged 19-78 yr with a body mass index of 18-39 kg/m(2) participated in the study. OUTCOMES OUTCOMES included nadir vs. peak GH concentrations and basal vs. pulsatile GH secretion. RESULTS Mean nadir GH concentrations were determined positively by sex hormone binding globulin (SHBG) after glucose administration (R(2) = 0.088, P = 0.0077). Peak rebound GH concentrations were related positively to adiponectin and negatively to computed tomography-estimated abdominal visceral fat (AVF) (R(2) = 0.182, P = 0.00049) after glucose ingestion. Deconvolution analysis showed that SHBG specifically predicted basal (nonpulsatile) GH secretion after glucose exposure (R(2) = 0.153, P = 0.00052). In contrast, together exercise history and adiponectin (both positively) and AVF (negatively) predicted pulsatile GH escape after glucose suppression (R(2) = 0.206, P = 0.00043). Moreover, adiponectin uniquely determined the size (mass), and AVF the mode (duration), of GH secretory bursts after glucose exposure (both P < 0.006). CONCLUSION Glucose ingestion provides a clinical model for investigating complementary metabolic surrogates that determine suppression and recovery of basal and pulsatile GH secretion in healthy men.
Collapse
Affiliation(s)
- Ali Iranmanesh
- Endocrine Research Unit, Mayo School of Graduate Medical Education, Center for Translational Science Activities, Mayo Clinic, Rochester, Minnesota 55905, USA
| | | | | |
Collapse
|
14
|
Lim SH, Vasanwala R, Lek N, Yap F. Quantifying the risk of hypoglycaemia in children undergoing the glucagon stimulation test. Clin Endocrinol (Oxf) 2011; 75:489-94. [PMID: 21609349 DOI: 10.1111/j.1365-2265.2011.04117.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
OBJECTIVE The low-dose (15-30 μg/kg) glucagon stimulation test (GST) is assumed to be associated with fewer episodes of low blood glucose (BG). We aimed to quantify the risk of hypoglycaemia in children undergoing the low-dose GST to evaluate their growth hormone status. DESIGN AND PATIENTS Blood glucose fluctuations during the GST in 80 children (median age 8·7 years, 45 boys, 66 prepubertal) who received a median 20·5 μg/kg of intramuscular glucagon were reviewed. MEASUREMENTS The rate of (i) hypoglycaemia (BG < 3·3 mm), (ii) falling BG trend at the end of the GST (lower BG at 180 min than at 120 min), (iii) hypoglycaemia and falling BG trend at the end of the GST, and (iv) at-risk patients (those with at least one of the three risks measures). RESULTS Twenty-seven of the 80 children had hypoglycaemia during the GST. Twenty-six children showed a falling BG trend at the end of the GST and were significantly younger than the other 54 children with a rising BG trend [5·1 (3·1-10·4) years vs 9·6 (5·4-11·8) years, P = 0·02]. Eight children had both a falling BG trend and hypoglycaemia at end of the test. Forty-four children were at-risk patients, and the odds ratio of being an at-risk patient in those <8 years old was 2·63 (95% CI 1·06-6·57, P = 0·04). CONCLUSIONS Hypoglycaemia is not uncommon during the low-dose GST. Young children, especially those <8 years old, are particularly at risk. BG monitoring should be considered essential from a safety perspective.
Collapse
Affiliation(s)
- Song Hai Lim
- Endocrinology Service, Department of Paediatrics, KK Women's and Children's Hospital, Singapore
| | | | | | | |
Collapse
|
15
|
Yuen KCJ. Glucagon stimulation testing in assessing for adult growth hormone deficiency: current status and future perspectives. ISRN ENDOCRINOLOGY 2011; 2011:608056. [PMID: 22363884 PMCID: PMC3262627 DOI: 10.5402/2011/608056] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 05/09/2011] [Accepted: 06/25/2011] [Indexed: 12/02/2022]
Abstract
Growth hormone deficiency (GHD) is a well-recognized clinical syndrome in adults. However, due to the high frequency of normal serum IGF-I levels in hypopituitary adults with GHD, it is now widely accepted that despite normal levels of total IGF-I, adults clinically suspected with GHD within the appropriate clinical setting must undergo GH provocative testing to confirm its diagnosis. Although the insulin tolerance test (ITT) is labor intensive, contraindicated in the elderly and in adults with seizure disorders and ischemic heart disease, can be unpleasant for the patient, and is potentially hazardous, this test remains the gold standard test for the biochemical demonstration of GHD in adults. In contrast, with the unavailability of the GHRH and arginine test as the alternative test to the ITT in the United States since 2008, the glucagon stimulation test (GST) has since been increasingly used in the United States because of its availability, reproducibility, safety, lack of influence by gender and hypothalamic cause of GHD, and relatively few contraindications. In this paper, we discuss our recommendations in performing this test, the potential drawbacks in conducting and caveats in interpreting this test, and its future perspectives.
Collapse
Affiliation(s)
- Kevin C J Yuen
- Division of Endocrinology, Diabetes and Clinical Nutrition, Oregon Health and Science University, Portland, OR 97239-3098, USA
| |
Collapse
|
16
|
Cook DM, Yuen KCJ, Biller BMK, Kemp SF, Vance ML. American Association of Clinical Endocrinologists medical guidelines for clinical practice for growth hormone use in growth hormone-deficient adults and transition patients - 2009 update. Endocr Pract 2010; 15 Suppl 2:1-29. [PMID: 20228036 DOI: 10.4158/ep.15.s2.1] [Citation(s) in RCA: 113] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
|
17
|
di Iorgi N, Napoli F, Allegri A, Secco A, Calandra E, Calcagno A, Frassinetti C, Ghezzi M, Ambrosini L, Parodi S, Gastaldi R, Loche S, Maghnie M. The accuracy of the glucagon test compared to the insulin tolerance test in the diagnosis of adrenal insufficiency in young children with growth hormone deficiency. J Clin Endocrinol Metab 2010; 95:2132-9. [PMID: 20350939 DOI: 10.1210/jc.2009-2697] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
CONTEXT The accuracy of the glucagon test in the diagnosis of central adrenal insufficiency in young children has not yet been definitively established. OBJECTIVE The aim of this study was to investigate the diagnostic accuracy of the glucagon test as an alternative to the insulin tolerance test (ITT) in children with GH deficiency under 6 yr of age. DESIGN AND SETTING This was a prospective study conducted in two Pediatric Endocrinology Centers. PATIENTS AND METHODS Forty-eight children (median age, 4.2 yr) with GH deficiency confirmed by a peak GH to ITT and arginine less than 10 microg/liter were enrolled: 24 with normal hypothalamic-pituitary anatomy, seven with isolated anterior pituitary hypoplasia, and 17 with structural hypothalamic-pituitary abnormalities at magnetic resonance imaging. Twelve subjects had central adrenal insufficiency defined by a peak cortisol response of less than 20 microg/dl to ITT. All children underwent a glucagon stimulation test with blood sampling for cortisol and glucose (time 0 to 180 min) after the im administration of 30 microg/kg of glucagon. RESULTS The mean peak cortisol after glucagon was not significantly different from that obtained after ITT in the whole cohort (25.9 vs. 26.0 microg/dl; P = 0.908), and it was significantly reduced in patients with structural hypothalamic-pituitary abnormalities (P < 0.001). Receiver operating characteristic curve analysis showed that the best diagnostic accuracy was obtained with a peak cortisol cutoff to glucagon of 14.6 microg/dl (sensitivity, 66.67%; specificity, 100%; area under the curve = 0.91; 95% confidence interval, 0.82-0.99). Using this cutoff, 91.67% of the patients were correctly classified. CONCLUSIONS This study shows that glucagon is an accurate and safe diagnostic test for adrenal function in young children who are at risk for adrenal insufficiency.
Collapse
Affiliation(s)
- Natascia di Iorgi
- Department of Pediatrics, Istituto di Ricovero e Cura a Carattere Scientifico G. Gaslini, University of Genova, Largo Gerolamo Gaslini, 5, 16147, Genova, Italy
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
18
|
Kamoi K, Shimatsu A, Kobayashi M. Is there an undiscovered neurocircuit for regulating GH secretion? -Pitfalls of GHRP-2 and ITT as GH provocative tests-. Endocr J 2010; 57:1071-9. [PMID: 20953065 DOI: 10.1507/endocrj.k10e-198] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
GH secretion is mainly regulated at the hypothalamus by a dual interplay between growth hormone releasing hormone (GHRH) and somatostatin, which are modulated by various factors. We examined the regulatory mechanism of GH secretion in an apparently healthy young man without decreased IGF-1 concentration and nocturnal GH secretion, but who showed low responses to insulin tolerance (ITT) and to GHRP-2 tests. The patient also had no GH response to acute aerobic exercise. However, he had normal secretion of pituitary hormone based on hypothalamic releasing hormone tests combined with CRH, GRH as GHRH, LH-RH and TRH. In addition, he had a GH response without paradoxical secretion to TRH stimulation as well as an ACTH response to subcutaneous glucagon stimulation, and AVP secretion responded to 5% hypertonic saline infusion, though it was not adequately stimulated by ITT. MRI showed no structural abnormalities in the hypothalamus-pituitary gland. These findings indicate that this subject may have an undiscovered neurocircuit for regulating GH secretion, as well as other neurohormones, to maintain homeostasis, even though there were low responses of the hormones to ITT and GHRP-2 stimuli, probably via altered secretion of hypothalamic hormones.
Collapse
Affiliation(s)
- Kyuzi Kamoi
- The Center of Diabetes and Endocrine & Metabolism Disease, Nagaoka Red Cross Hospital, Nagaoka, Japan.
| | | | | |
Collapse
|
19
|
Secco A, di Iorgi N, Napoli F, Calandra E, Ghezzi M, Frassinetti C, Parodi S, Casini MR, Lorini R, Loche S, Maghnie M. The glucagon test in the diagnosis of growth hormone deficiency in children with short stature younger than 6 years. J Clin Endocrinol Metab 2009; 94:4251-7. [PMID: 19837934 DOI: 10.1210/jc.2009-0779] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CONTEXT Few studies have addressed the diagnostic role of the glucagon test in children with suspected GH deficiency (GHD). OBJECTIVE The objective of the study was to investigate the diagnostic value of the glucagon test as an alternative test to insulin tolerance test (ITT) and arginine in GHD children younger than 6 yr. DESIGN AND SETTING This study was conducted in two pediatric endocrinology centers. PATIENTS AND METHODS Forty-eight children (median age 4.2 yr, median height -3.0 sd score) with GHD confirmed by a peak GH to ITT and arginine less than 10 microg/liter (median 4.7 and 3.4 microg/liter, respectively) underwent a glucagon stimulation test. Magnetic resonance imaging showed normal hypothalamic-pituitary anatomy in 24 children, isolated anterior pituitary hypoplasia in seven, and structural hypothalamic-pituitary abnormalities in 17. RESULTS Median GH peak response to glucagon (13.5 microg/liter) was significantly higher than that observed after ITT and arginine (P < 0.0001). GH peak after glucagon was less than 10 microg/liter in 20 subjects (group 1) and greater than 10 microg/liter in 28 subjects (group 2) without significant clinical or biochemical differences between the two groups. Median GH peak after glucagon was similar between patients with multiple pituitary hormone deficiency and those with isolated GHD and between subjects with and without structural hypothalamic-pituitary abnormalities. The magnitude of the GH peak after glucagon was negatively correlated to age at diagnosis (rho = -0.636, P < 0.0001). CONCLUSIONS This study shows that glucagon has an effective GH-releasing activity and can be used to evaluate somatotroph function in young children with short stature. Normative data for this test in young children need to be established before its use in clinical practice.
Collapse
Affiliation(s)
- Andrea Secco
- Department of Pediatrics, Istituto di Ricovero e Cura a Carattere Scientifico G Gaslini Institute, University of Genova, 16147 Genova, Italy
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
20
|
Yuen KCJ, Biller BMK, Molitch ME, Cook DM. Clinical review: Is lack of recombinant growth hormone (GH)-releasing hormone in the United States a setback or time to consider glucagon testing for adult GH deficiency? J Clin Endocrinol Metab 2009; 94:2702-7. [PMID: 19509104 DOI: 10.1210/jc.2009-0299] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CONTEXT The use of the combined GHRH and arginine (GHRH-ARG) test has gained increasing acceptance in the United States as a reliable alternative test to the insulin tolerance test (ITT) for diagnosing adult GH deficiency (GHD). In July 2008, the only manufacturer of recombinant GHRH in the United States, EMD Serono, Inc., announced the discontinuation of Geref, thus raising the question of which reliable alternative GH stimulation test should practicing endocrinologists be considering in place of the GHRH-ARG test. In this article, we review the existing published data and consensus guidelines and provide recommendations for alternative stimulation tests to the GHRH-ARG test. EVIDENCE ACQUISITION The major source of data acquisition included PubMed search strategies and personal experience of the authors from clinical experience. EVIDENCE SYNTHESIS Previous consensus guidelines and previous data assessing the reliability and discriminatory value of the GHRH-ARG, glucagon, ARG, and GH secretagogues on assessing GH reserve are discussed. Our recommendations for performing the glucagon stimulation test, potential drawbacks in conducting this test, and caveats in interpreting this test are also discussed. CONCLUSIONS The ITT should remain the test of choice in diagnosing adult GHD. However, when the ITT is not desirable and recombinant GHRH remains unavailable in the United States, we recommend the alternative to the GHRH-ARG test to be the glucagon stimulation test, based on its reliability and availability. Nevertheless, further studies into alternative GH stimulation tests that are available in the United States, comparable, and simpler to perform than the ITT in diagnosing adult GHD are still needed.
Collapse
Affiliation(s)
- Kevin C J Yuen
- Division of Endocrinology, Diabetes and Clinical Nutrition, Oregon Health and Science University, 3181 SW Sam Jackson Park Road, Portland, OR 97239-3098, USA.
| | | | | | | |
Collapse
|