Maintenance of Basal Plasma Glucose and Insulin Concentrations in Maturity-Onset Diabetes

Abstract

Normal and mildly diabetic subjects each have their own "set" of basal plasma glucose and insulin concentrations. Diabetic patients have raised basal plasma glucose, with low-normal basal plasma C-peptide concentrations. Restoring normal glucose levels in mild diabetes by an insulin infusion further reduces the C-peptide concentration, but both the plasma glucose and the C-peptide return to their "set" level when the insulin is withdrawn. These results accord with the action of beta cells and liver in a negative feedback loop that maintains basal plasma glucose and insulin concentrations.

Sulphonylurea therapy doubles B-cell response to glucose in Type 2 diabetic patients

“…The fasting plasma insulin and C-peptide concentrations were not significantly higher on sulphonyurea therapy than on diet alone, although other studies have reported significantly increased fasting C-peptide levels on sulphonylurea treatment [3,16]. This is compatible with a slightly reduced basal insulin secretion in Type 2 diabetes being an "error signal" maintaining basal hyperglycaemia [16].…”

“…This is compatible with a slightly reduced basal insulin secretion in Type 2 diabetes being an "error signal" maintaining basal hyperglycaemia [16]. With improved B-cell efficiency, both the hyperglycaemia decreases and the reduced basal insulin level rises.…”

UK prospective study of therapies of maturity-onset diabetes

“…A more logical criterion of control would be to aim for basal normoglycaemia, and this can be obtained with either ultralente insulin [11] or chlorpropamide [12]. The overnight basal plasma glucose concentration is relatively repeatable in a diabetic patient in a given nutritional state [13]. In practice it is reasonable to aim for a fasting plasma glucose of<6mmol/1, and this means of control has been shown to be acceptable in an unselected group of maturity-onset diabetic patients [14], with a reduction of the raised fasting plasma glucose being accompanied by a reduced haemoglobin At.…”

Counterpoint: Appreciating Homeostasis Model Assessment

“…The "basal state " must be clearly defined. Overnight fasted subjects were either 1) admitted at least the previous evening and sampled either between 0300 and 0500 h (overnight basal) or between 0630 and 0730 h (morning basal) or 2) they traveled from home that morning and rested for 30 min before sampling (stressed fasting) (32). HOMA-B values differed significantly in the latter, at 101% for nondiabetic individuals and 45% for diabetic individuals, from the values for the two insignificantly different basal states (150 and 162% for normal subjects and 117 and 101% for the diabetic subjects).…”