Biochemical evidence for the requirement of continuous glucose therapy in young adults with type 1 glycogen storage disease.

To determine whether patients with GSD-1 need nocturnal glucose therapy after completing physical growth and development, studies were performed on two consecutive nights. On the first night uncooked cornstarch (UCS) was given at the calculated glucose production rate at 21:00 h and 02:00 h. On the second night UCS was given at 21:00 h but omitted at 02:00 h. Six GSD-1 patients, aged 17.2-20.9 years, previously treated with continuous glucose therapy were studied. Measurements were made of plasma glucose (PG), serum insulin, growth hormone, cortisol, plasma glucagon (n = 4), and blood lactate at 30-60-min intervals. Serum uric acid, cholesterol, and triglycerides were measured at 21:00 h and 07:00 h, and serum FFA at 21:00 h, 02:00 h and 07:00 h on the first night and immediately before treatment for hypoglycaemia on the second night. For five hours after UCS at 21:00 h, mean PG, serum insulin and blood lactate concentrations were similar on the two nights. With UCS at 02:00 h, mean PG concentrations were > or = 4.1 mmol/L from 02:00 to 07:00 h. Without UCS at 02:00 h, in all subjects PG concentrations fell to < 2.5 mmol/L after 6.5-8.5 h and mean blood lactate concentration increased to 7.4 +/- 3.0 mmol/L. Young adults with GSD-1 developed hypoglycaemia and hyperlactataemia after a relatively brief period without exogenous glucose and, therefore, need to continue nocturnal glucose therapy to prevent fasting hypoglycaemia.