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Neuroendocrinology and Pituitary

SUN-026 - Growth Hormone Suppression in Healthy Volunteers: Can A More Palatable Mixed Meal Tolerance Test Replace the Standard Oral Glucose Tolerance Test ?

Sunday, June 14, 2026
9:00 AM - 4:00 PM CT
Location: ENDOExpo; Poster Floor

    Abstract Poster Presenter(s)

  • Jeyakantha Ratnasingam, MD (he/him/his)

    Professor of Medicine
    University Malaya Medical Centre
    Selangor, Malaysia

    • Senior Author/Primary Investigator(s)

  • Jeyakantha Ratnasingam, MD (he/him/his)

    Professor of Medicine
    University Malaya Medical Centre
    Selangor, Malaysia

    • Co-Author(s)

  • KV

    KAHVITHAA VIJAYAN, MMed

    Endocrine Unit, Department of Medicine, University Malaya Medical Centre, Kuala Lumpur, Malaysia
    Selangor, Malaysia

  • YO

    Ying Guat Ooi, MRCP

    Endocrine Unit, Department of Medicine, University Malaya Medical Centre, Kuala Lumpur, Malaysia
    Selangor, Malaysia

  • JK

    Jun-Kit Khoo, MRCP

    Endocrine Unit, Department of Medicine, University Malaya Medical Centre, Kuala Lumpur, Malaysia
    Selangor, Malaysia

  • QL

    Quan-Hziung Lim, MMed

    Endocrine Unit, Department of Medicine, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
    Selangor, Malaysia

  • TS

    Tharsini Sarvanandan, MRCP

    Endocrine Unit, Department of Medicine, University Malaya Medical Centre, Kuala Lumpur, Malaysia
    Selangor, Malaysia

  • NK

    Nicholas Ken Yoong Hee, MRCP

    Endocrine Unit, Department of Medicine, University Malaya Medical Centre, Kuala Lumpur, Malaysia
    Selangor, Malaysia

  • PS

    Pavai Sthaneswar, MD, MME

    Division of Laboratory Medicine, Department of Pathology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
    Kuala Lumpur, Malaysia

  • LL

    Lee-Ling Lim, PhD, FRCP

    Endocrine Unit, Department of Medicine, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
    Kuala Lumpur, Malaysia

  • MD

    Mahmoud Danaee, PhD

    Department of Social and Preventive Medicine, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
    Kuala Lumpur, Malaysia

  • CL

    Ching Li Lee, PhD

    Department of Nutrition, Dietetics and Food Sciences, School of Health Sciences, IMU University, Kuala Lumpur, Malaysia
    Kuala Lumpur, Malaysia

  • SV

    Shireene Vethakkan, MD

    Endocrine Unit, Department of Medicine, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
    Selangor, Malaysia

Disclosure(s):
Jeyakantha Ratnasingam, MD: No financial relationships to disclose


Background:
The 75gm oral glucose tolerance test (OGTT) is the gold standard for assessment of GH suppression in acromegaly but the test is poorly tolerated and may cause reactive hypoglycemia. The more palatable mixed meal tolerance test (MMTT) could be an alternative, though comparative data are lacking. This pilot study aims to compare GH suppression between OGTT and MMTT in healthy individuals.

Methods:
This study involved healthy subjects who underwent both OGTT and MMTT two weeks apart. A breakfast consisting of two slices of bread (57gm) with jam (20gm) and a glass of orange juice (290ml) was designed as the MMTT to give rise to similar glycemic carbohydrate (74.6gm) to the 75gm OGTT. Serum glucose and GH levels were measured at baseline and at 30-minute intervals over a 120-minute period, after an overnight fast. The Bland-Altman plot was used to examine the level of agreement between both methods.

Results:
We analysed 13 healthy volunteers (62% male, mean age: 23.5±1.5 years, mean BMI: 21.1kg/m²). All subjects had normal age- and sex-matched IGF-1 levels (mean, 158.8 ng/mL, reference interval: 98.7 – 289). Glucose levels were consistently higher after the OGTT compared to the MMTT, with an overall mean difference of 0.94 mmol/L (95% CI: 0.61-1.27 mmol/L, p < 0.01). However, GH results showed no significant difference, with an overall mean difference of 0.05 ng/mL (95% CI: -0.32 to 0.42 ng/mL, p = 0.79), indicating high level of agreement. The level of agreement was consistent across all timepoints, indicating concordant GH suppression between the MMTT and OGTT.

Conclusion:
GH suppression with MMTT showed high level of concordance with the gold-standard OGTT, making MMTT a potential alternative for assessing GH suppression with glucose load. Future studies in people with acromegaly are required to validate these findings.

*Unless otherwise noted, all abstracts presented at ENDO must not be released to the press or the public until the date and time of presentation. For oral presentations, the abstracts are embargoed until the session begins. The Endocrine Society reserves the right to lift the embargo on specific abstracts that are selected for promotion prior to or during ENDO.*