NCT00992901

Hormonal and Neural Control of Insulin Secretion Following Gastric Bypass Surgery

Recruiting now EARLY_PHASE1 Last updated 8 September 2025

What this trial tests

EARLY_PHASE1 trial testing Exendin-(9-39) in Post Bariatricsurgery in 160 participants. Currently enrolling.

Timeline

1 October 2009

Primary endpoint
1 August 2026

1 August 2027

Quick facts

Lead sponsor	The University of Texas Health Science Center at San Antonio
Phase	EARLY_PHASE1
Status	Recruiting now
Study type	INTERVENTIONAL
Allocation	non randomized
Design	crossover
Masking	none
Primary purpose	other
Enrollment	160
Start date	1 October 2009
Primary completion	1 August 2026
Estimated completion	1 August 2027
Sites	2 locations across United States

Drugs / interventions tested

• Exendin-(9-39)
• Atropine (ATROPINE) — full drug profile →
• GLP-1 and GIP — full drug profile →

Conditions studied

• Post Bariatricsurgery — all drugs for Post Bariatricsurgery →
• Hypoglycemia — all drugs for Hypoglycemia →

Sponsor

The University of Texas Health Science Center at San Antonio

Who can join

Adults 18 to 65, any sex, with Post Bariatricsurgery or Hypoglycemia. Healthy volunteers can join.

What's being measured

Primary outcomes are the specific endpoints the trial is designed to prove or disprove.

• Gut hormones and neural signaling contribution to insulin secretion rate and glucose tolerance
  Time frame: Each study of the protocol is conducted up to seven hours with data collected at intervals specific to the individual study procedure.

Sponsor's own description

RYGB (roux-en-y gastric bypass) has been reported to reverse type 2 diabetes (T2DM) immediately after surgery before any significant weight loss. In addition, a growing number of patients have been recognized with life-threatening hyperinsulinemic hypoglycemia several years following their surgery. While the mechanisms by which RYGB improves glucose metabolism or alters islet cell function in patients after RYGB are not understood, recent studies suggest that increased secretion of GI hormones, primarily glucagon-like peptide 1 (GLP-1), as well as alteration in neural activity may contribute to enhanced insulin secretion in general, and to a greater extent in patients with hypoglycemia. The proposed research is designed to address the role of RYGB on insulin secretion by evaluating the contribution of stimulatory factors (neural and GI hormone) on islet cell function and the islet cell responsiveness to the physiologic stimulatory factors, in RYGB patients with and without hypoglycemia and non-operated controls.

Publications & conference data

2 peer-reviewed publications reference this trial (live from Europe PMC):

1. Functional GLP-1R antibodies identified from a synthetic GPCR-focused library demonstrate potent blood glucose control.
   Liu Q, Garg P, Hasdemir B, Wang L, et al · · 2021 · cited 16× · PMID 33706686 · DOI 10.1080/19420862.2021.1893425
2. Cholinergic signaling mediates the effects of xenin-25 on secretion of pancreatic polypeptide but not insulin or glucagon in humans with impaired glucose tolerance.
   Wang S, Oestricker LZ, Wallendorf MJ, Sterl K, et al · · 2018 · cited 10× · PMID 29466430 · DOI 10.1371/journal.pone.0192441