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Trial registered on ANZCTR


Registration number
ACTRN12612000826842
Ethics application status
Approved
Date submitted
3/08/2012
Date registered
6/08/2012
Date last updated
31/10/2016
Type of registration
Prospectively registered

Titles & IDs
Public title
Effects of small intestinal L-glutamate and L-glutamine infusions on gut motility, gut hormone release and blood glucose control in healthy humans.
Scientific title
Effects of small intestinal L-glutamate and L-glutamine infusions on antropyloroduodenal motility, gut hormone release, blood glucose control and energy intake in healthy, normal weight subjects.
Secondary ID [1] 280970 0
nil
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Obesity 287080 0
Healthy human physiology 287097 0
Condition category
Condition code
Diet and Nutrition 287405 287405 0 0
Obesity
Oral and Gastrointestinal 287408 287408 0 0
Normal oral and gastrointestinal development and function

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
Regulation of the factors that control food intake, the function of the stomach and small intestine and release of gut hormones is complex, and our understanding of this field is far from complete. There is increasing evidence that nutrient stimuli in the gut, especially in the small intestine, induce changes in gut motor and hormonal functions that play a central role in the control of energy intake and blood glucose. In particular high-protien diets have been found to be very effective for weight loss and for improving blood glucose in obese with and without type 2 diabetes.
This study aims to investigate the effects of amino acids, L-glutamate and L-glutamine on gut motility, gut hormone release, blood glucose control and energy intake in humans. We hypothesise that L-glutamate and L-glutamine, as building blocks of protiens, may substantially contribute to the benefical effects of whole protien on gut functions and energy intake regulation.
A total of 20 Caucasian male and female (BMI 18-25 kg/m2) subjects, aged between 18 - 50 years, will be included in the study. Each subject will be studied on four occasions. On each occasion, they will recieve, in randomised, double-blind fashion, a 90-min intraduodenal infusion of (i) L-glutamate at 0.2 kcal/min (4.4 g/90 min), (ii), L-glutamine at 0.2 kcal/min (4.4 g/90 min), (iii) L-glutamine at 0.4 kcal/min (8.8 g/90 min) or (iv) saline (negative control). Gut motility, blood glucose, gut hormone release, insulin concentrations, appetite perceptions and energy intake during a buffet meal , as well as vital signs, will be measured. The buffet meal will be provided at the end of each of the four infusions and the participant has 30mins to eat until comfortably full. The buffet meal consists of 300ml orange juice, 600ml water, 375ml iced coffee, 4 slices of white bread, 4 slices of brown bread, 100g deli leg ham, 100g virginian chicken, 4 slices cheese, 100g tomato, 100g cucumber, 100g lettuce, 2 portions mayonnaise, 2 portions margarine, 1 medium apple, 1 medium banana, 200g chocolate custard, 150g fruit salad, 200g strawberry yoghurt, and 14g milkyway chocolate bar. Each volunteer will recieve one of each infusion solutions on each of the four study days. Each study day will be seperated by no less than three days.
Intervention code [1] 285413 0
Treatment: Other
Comparator / control treatment
Saline
Control group
Placebo

Outcomes
Primary outcome [1] 287668 0
Antropyloroduodenal motility (number of antral, duodenal and isolated pyloric pressure waves, and basal pyloric pressure.
Timepoint [1] 287668 0
Using a manomentry assembly and catheter, antropyloroduodenal pressures will be continously monitored from intubation until 90minutes (end of infusion) for all four infusion sessions.
Primary outcome [2] 287672 0
Plasma concentrations of gastrointestinal hormones (e.g. CCK, GLP-1, PYY, GIP and ghrelin, and potentially other, yet to be identified gut hormones), insulin and glucose.
Timepoint [2] 287672 0
Gut hormone release will be assessed by enzyme-linked immunosorbent assay (ELIZA) or radio immunosorbent assay (RIA) from blood samples taken at t= -10, 0, 15, 30, 45, 60, 75, 90 and 120 minutes, in each of the four sesssions.
Secondary outcome [1] 298609 0
Appetite sensations using a Visual Analogue Scale (VAS) (satiety, hunger, fullness, thrist, desire to eat and amount of food desire to eat) and macronutrient and total energy intake and the buffet meal
Timepoint [1] 298609 0
VAS questionnaires are taken at = -10, 0, 15, 30, 45, 60, 75, 90 and 120 minutes, at each of the four sessions. The buffet meal will be presented at 90 mins when the infusion ends and the subject will be allowed to freely consume food until comfortable full for 30 mins (until t=120mins)

Eligibility
Key inclusion criteria
A total of 20 Caucasian male and female (BMI 18-25 kg/m2) subjects, aged between 18 - 50 years, will be included in the study. All subjects will be required to be weight-stable (i.e. less than 5 % fluctuation in their body weight) at study entry, as determined by their self-reported weight in the preceding 3 months, and will be required to maintain their normal physical activity over the course of the study.
Minimum age
18 Years
Maximum age
50 Years
Gender
Both males and females
Can healthy volunteers participate?
Yes
Key exclusion criteria
Significant gastrointestinal symptoms, disease or surgery, use of prescribed or non-prescribed medications (including vitamins and herbal supplements) which may affect energy metabolism, gastrointestinal function, body weight or appetite (eg domperidone and cisapride, anticholinergic drugs (eg atropine), metoclopramide, erythromycin, hyoscine, orlistat, green tea extracts, Astragalus, St Johns Wort etc.)
lactose intolerance/ MSG intolerance/other food allergy(ies), current gallbladder or pancreatic disease, diabetes mellitus, as defined by fasting glucose greater than 6.9 mmol/l and/or glycated haemoglobin equal to 6.2 %, cardiovascular or respiratory diseases, individuals with low ferritin levels (females less than 15 ng/mL, males less than 30 ng/mL), or who have donated blood in the 12 weeks prior to taking part in the study, any other illnesses as assessed by the investigator (including chronic illnesses not explicitly listed above), high performance athletes, current intake of greater than 2 standard drinks on greater than 5 days per week, current smokers of cigarettes/cigars/marijuana, current intake of any illicit substance, vegetarians. In female subjects, pregnancy or lactation.

Study design
Purpose of the study
Treatment
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Volunteers are asked to visit the clinic for a 30 minute screening visit. A questionnaire is answered by the volunteer, based on the inclusion/exclusion criteria and eligibility is determined. A signed informed consent is obtained and study dates are established. Eligable volunteers are assigned a subject number and randomised treatment for each study visit, using a randomised table which was created on an excel spread sheet. Randomisation involved contacting the holder (study assistant) of the randomisation table to inform them of the next subjects details and study dates. The unblinded study assistant is therefore responsible for allocationg a random treatment to the subject and preparing the solution on each study day.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
The randomisation table was generated using Microsoft Office Excel.
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?



Intervention assignment
Crossover
Other design features
Phase
Not Applicable
Type of endpoint(s)
Pharmacokinetics / pharmacodynamics
Statistical methods / analysis

Recruitment
Recruitment status
Completed
Date of first participant enrolment
Anticipated
Actual
Date of last participant enrolment
Anticipated
Actual
Date of last data collection
Anticipated
Actual
Sample size
Target
Accrual to date
Final
Recruitment in Australia
Recruitment state(s)
SA

Funding & Sponsors
Funding source category [1] 285753 0
Hospital
Name [1] 285753 0
Gum Bequest Grant, Royal Adelaide Hospital Endocrine Unit
Address [1] 285753 0
Royal Adelaide Hospital
North Terrace,
Adelaide, SA 5000
Country [1] 285753 0
Australia
Primary sponsor type
Individual
Name
Christine Feinle-Bisset
Address
Level 6 Eleanor Harrald Building,
Frome Road,
Adelaide, SA 5000
Country
Australia
Secondary sponsor category [1] 284582 0
Individual
Name [1] 284582 0
Robert E Steinert
Address [1] 284582 0
Level 6 Eleanor Harrald Building,
Frome Road,
Adelaide, SA 5000
Country [1] 284582 0
Australia

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 287766 0
Royal Adelaide Hospital Research Ethics Committe
Ethics committee address [1] 287766 0
Level 3, Hanson Institute
North Terrace
Adelaide SA, 5000
Ethics committee country [1] 287766 0
Australia
Date submitted for ethics approval [1] 287766 0
Approval date [1] 287766 0
12/07/2012
Ethics approval number [1] 287766 0
120707

Summary
Brief summary
Regulation of the factors that control food intake, the funtion of the stomach and small intestine and release of gut hormones is complex, and our understanding of this feild is far from complete. There is increasing evidence that nutrient stimuli in the gut, especially in the small intestine, induce changes in gut motor and hormonal functions that play a central role of energy intake and blood glucose. In particular high-protien diets have been found to be very effective for weight loss and for improving blood glucose in obese subjects with and without type 2 diabetes. This study aims to investigate the effects of the amino acids, L-glutamate and L-glutamine, on gut motility, gut horone release, blood glucose control and energy intake. We hypothesise that L-glutamate and L-glutamine as building blocks of proteins, may substantially contribute to the beneficial effects of whole protein on gut functions and energy intake regulation. This has not yet been evaluated in detail and will be important in order to enhance our understanding of the mechanisms underlying the effects of dietary protein on eating control.
Trial website
Trial related presentations / publications
Steinert RE, Landrock MF, Horowitz M, Feinle-Bisset C. Intraduodenal infusions of L-phenylalanine and L-glutamine differentially affect antropyloroduodenal motility and plasma cholecystokinin in healthy men. J Neurogastroenterol Motil (accepted 6th Jan 2015)
Public notes

Contacts
Principal investigator
Name 34535 0
Dr Dr Robert E Steinert
Address 34535 0
Level 6 Eleanor Harrald Building, Frome Road, Adelaide, SA 5000
Country 34535 0
Australia
Phone 34535 0
+61 8 8222 5039
Fax 34535 0
Email 34535 0
robert.steinert@adelaide.edu.au
Contact person for public queries
Name 17782 0
Dr Dr Robert E Steinert
Address 17782 0
Level 6 Eleanor Harrald Building,
Frome Road,
Adelaide, SA 5000
Country 17782 0
Australia
Phone 17782 0
+61 8 8222 5039
Fax 17782 0
Email 17782 0
robert.steinert@adelaide.edu.au
Contact person for scientific queries
Name 8710 0
Dr Dr Robert E Steinert
Address 8710 0
Level 6 Eleanor Harrald Building,
Frome Road,
Adelaide, SA 5000
Country 8710 0
Australia
Phone 8710 0
+61 8 8222 5039
Fax 8710 0
Email 8710 0
robert.steinert@adelaide.edu.au

No information has been provided regarding IPD availability
Summary results
Have study results been published in a peer-reviewed journal?
Other publications
Have study results been made publicly available in another format?
Results – basic reporting
Results – plain English summary