Role of Hepatic Glycogen on Nocturnal EGP in T2D
Phase: NA
Conditions: Diabetes Mellitus, Diabetes Mellitus, Type 2
Sponsor: University of Alabama at Birmingham

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Role of Hepatic Glycogen on Nocturnal EGP IN T2D 
 
 
 
Unique Protocol ID: 22074 
Secondary ID: R01DK029953 
ClinicalTrials.gov ID: NCT04416204 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

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Protocol:  
15 ND and 14 T2D subjects will be studied on two occasions (glycogen loading vs. no 
glycogen loading). Human Subjects: All studies and protocols will be approved by the 
UVA Institutional Review Board. These studies will be conducted in 15 T2D and 15 ND 
subjects (age 30 - 80 years, BMI 20 - 35 kg/m2) matched for age and degree of obesity. 
Menstruating female subjects will be studied during the follicular phase of their 
menstrual cycles Screen visit: Subjects will report to the UVA CRU after an overnight 
fast in the morning. After obtaining informed consent, a history and physical 
examination will be performed. Blood will be collected for complete blood count, serum 
creatinine, electrolytes, lipids, and HbA1c. A standard urinalysis will be performed. All 
women of childbearing potential will have a negative pregnancy test within 24 hours of 
the study visit. A dietary history will be taken at the time of screening to ensure 
adherence to a weight maintaining diet consisting of ~ 200 grams of carbohydrates per 
day and their diets met ADA guidelines for protein, fat, and carbohydrates. They will be 
instructed to adhere to the diet between screen and study visits. Body composition may 
be measured using measuring scale. Enrolled T2D subjects will withdraw oral 
hypoglycemic agents 2 weeks prior to study visit (medications will resume after each 
study visit) and will monitor their fingerstick glucoses. If three successive fingerstick 
glucose values ≥ 300 mg/dl, then they will resume their medication/s and will be 
withdrawn from study. Physical activity will be assessed with the Paffenbarger activity 
questionnaire and activity monitored by the subject with a Fitbit. Subjects will refrain 
from unusual / unaccustomed physical activity and should not change their body weight 
by >2% between screen and study visits. Pre-study visit protocols: All subjects will 
participate in both protocols outlined below in random order prior to their study visits. 
The study visits will be separated by 3-6 weeks to allow for elimination of deuterated 
water and will be identical except for the preceding glycogen loading or no glycogen 
loading protocols.  
Glycogen loading (GL) protocol: Subjects will consume an isocaloric diet [60% carbs, 
20% protein, 20% fat (33 kcal/kg/day)] prepared by the research dietician of the UVA 
CRU for 3 days prior to the overnight study 1. During this period, subjects will limit their 
daily activity to normal walking that will be monitored with Fitbit. Unusual physical 
activity will be discouraged.  
No glycogen loading (NGL) protocol: Subjects will consume an isocaloric diet [40% 
carbs, 20% protein, 40% fat (33 kcal/kg/day)] prepared by the research dietician of the 
UVA CRU for 3 days prior to the overnight study 2. During this period, subjects will do 
their normal walking (monitored by Fitbit) but unusual physical activity will be 
discouraged.  
Sample size estimation: The experimental design was configured with parallel cohorts 
(ND and T2D) with primary hypotheses of within cohort comparisons (i.e., glycogen 
loaded (GL) vs. non-glycogen loaded (NGL) meals). For sample size planning 
purposes, a paired t-test was utilized. At time of study design, no preliminary data 
existed on the effect of post prandial glucose uptake, so the effect size observed was 
utilizing a similar overnight study estimating GNG 3. For the studied T2D participants, 
the mean (SD) GNG (μmol/Kg/min) rate at 0700 hrs. was 12.9 (2.8) and 10.6 (3.0) 
under test and control conditions. This resulted in a change of 2.05 (1.68) between the 
two conditions. Assuming a similar magnitude of change of 2 units is clinically relevant 

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and a SD of the difference of 1.75 (to be conservative), a sample size of 9 was required 
to achieve 80% power at the alpha=0.05 level of significance. The protocol was written 
to study up to 15 participants per cohort to provide additional precision in the estimates 
and address the uncertainty in the glycogen loading effect. Primary analysis. A linear 
mixed model with compound symmetry variance structure was fit to the data that had 
repeated measurements at 0100, 0400 and 0700 hrs. This model specified parameters 
for study group (T2D vs. ND), time of night (0100, 0400 and 0700 hrs) and the glycogen 
loading treatment (GL vs NGL). This model estimated 12 (2 * 3 * 2) individual means for 
each outcome measure, with GNG planned as the primary endpoint at time of study 
planning. In order to summarize the effects of the model, model-based means were 
constructed to provide pooled estimates of the differences in means of interest. In some 
cases, several of the model-based means were averaged together (e.g., a “diabetes” 
effect was obtained by comparing the mean of the 0100, 0400 and 0700 hrs measures 
under both GL and NGL values averaged for each patient group). All p-values are 
unadjusted and reported in conjunction with estimates and 95% confidence intervals. 
Statistical analysis was performed using R version 4.1.2. 
 
Reference  
 
1. Petersen KF, Price T, Cline GW, Rothman DL, Shulman GI. Contribution of net 
hepatic glycogenolysis to glucose production during the early postprandial 
period. Am J Physiol. 1996;270(1 Pt 1):E186-91. PubMed PMID: 8772491. 
2. Garg A, Bantle JP, Henry RR, Coulston AM, Griver KA, Raatz SK, Brinkley L, 
Chen YD, Grundy SM, Huet BA, et al. Effects of varying carbohydrate content of 
diet in patients with non-insulin-dependent diabetes mellitus. JAMA. 
1994;271(18):1421-8. Epub 1994/05/11. PubMed PMID: 7848401. 
3. Basu A, Joshi, N, Miles, J, Carter, R, Rizza, R, Basu, R. Paradigm shifts in 
Nocturnal Glucose Control in Type 2 Diabetes. J Clin Endocrinol Metab. 
2018;103(10):3801-9. doi: DOI: 10.1210/jc.2018-00873; PMCID: PMC6179178.