Determination of pancreatic and gut Glucagon-Like Immunoreactivity (GLI) in normal and diabetic subjects

Abstract

Oral glucose tolerance tests (1.75 g glucose/ kg ideal body weight) were performed in 29 normal subjects, 17 maturity-onset diabetics (D I) and 8 juvenile type diabetics (D II). Glucose, IRI, pancreatic and gut ghcagon-like immunoreactivity (GLI) were determined at various intervals. The basal levels of pancreatic GLI in the three groups were as follows: normals: 0.33 :~ 0.03; D I: 0.43-u0.06; and D II: 0.50-t-0.05 ng equiv./m1 (mean • s.e.m.). After glucose, a significant decrease in pancreatic GLI was observed in the normals, whereas the diabetics showed no significant change. An increase in gut GLI was observed in all persons. The importance of the GLI levels and variations is discussed.

Insuppressibility of plasma glucagon by orally or intravenously administered glucose in diabetes mellitus.

“…The present experiments confirm the previous observations by Muller et al (1970), Buchannan and McCarrol (1972) and Heding and Rasmussen (1972) that glucagon secretion is not as readily suppressed by ingested glucose in diabetics as in normal subjects.…”

“…Based on the study of human diabetes, Unger (1971) has proposed that diabetes mellitus is a bihormonal disorder characterized by excessive glucagon and diminished insulin secretion. However, only a few reports have appeared on the plasma glucagon response to glucose loading in diabetes mellitus (Muller et al,1970;Buchannan and McCarrol, 1972;Heding and Rasmussen, 1972 ;Gossain et al, 1974), although plasma insulin response to glucose has been very extensively studied. The present study was carried out to clarify plasma glucagon responses to oral or intravenous glucose loading in patients with diabetes mellitus varying in its severity and to compare them with those in normal subjects.…”

Glucagon levels in normal and diabetic subjects: Use of a specific immunoabsorbent for glucagon radioimmunoassay

“…This is not likely to be the result of any dietary difference as only extremes of protein or carbohydrate intake influence basal glucagons [23]. Absolute differences of this magnitude between diabetics and controls have been reported by others [9,10,11]. However, overall values for both control and diabetic subjects are much lower than those reported by other laboratories using less specific assay methods.…”

“…Fasting levels of pancreatic glucagon in this assay system were much lower than those reported from other laboratories [6,7,10,11,22]. The levels are similar to the charcoal-corrected values obtained by Weir and associates [4], however, suggesting that "true" fasting levels of pancreatic glucagon are lower than previously accepted values.…”

“…Only this will enable genuine hormone concentrations to be measured in the unknown plasma samples. The failure to achieve this ideal in most current assays and the variability of such interference in different assays probably accounts for the big discrepancies reported in the literature for fasting levels in diabetic subjects of pancreatic glucagon, which has been quoted as low [5], normal [4,6,7,8], or raised [9,10,11]. In order to circumvent the problem, a technique has been developed whereby the glucagon content of each plasma is measured against a standard curve made up in an aliquot of the same plasma, made free of glucagon by prior extraction with a specific glucagon immunoabsorbent.…”