Data Sources
Three articles by a Mayo Clinic team under the leadership of Andy Basu provide the database for analyzing glucagon diurnal plasma profiles:
Diurnal pattern to insulin secretion and insulin action in healthy individuals; Diabetes 61:2691-700 2012.
Diurnal pattern of insulin action in type 1 diabetes; Diabetes 62:2223-9 2013.
A novel natural tracer method to measure complex carbohydrate metabolism; Am J Physiol Endocrinol Metab 317:E483-93 2019.
The first two “diurnal studies” were designed to determine whether there is a daily pattern of changing glucose tolerance following mixed meals which should be incorporated in the design of dosing algorithms for Automated Insulin Delivery systems. The third “carbohydrate study” was designed to test a new way of measuring insulin sensitivity and beta-cell responsivity to simple and complex carbohydrates. The study parameters relevant for the modeling in these papers are summarized in Exhibit 1.
A Java program called Plot Digitizer [1] was used to convert the data points shown in the article charts into tables of circulating concentrations. This process introduces small random variations between the actual study data and the results used in this analysis, and it could be expected to lower the R-squared values slightly.
The diurnal study profiles of glucose, insulin, and glucagon are shown in Exhibits 2 and 3 (copied directly from the charts of the referenced articles).
The carbohydrate study profiles of these analytes are shown in Exhibit 4 (also copied directly from the charts of the referenced article).
The error bars in the diurnal studies are smaller than those in the carbohydrate study, presumably because of the difference in the number of subjects (20 and 19 vs. 8).