SummaryThe effect of ingestion of uncooked cornstarch (2 g/kg body weight) in water, uncooked starch (1 g/kg) added to a meal, and glucose (2 g/kg) in water, was studied in eight patients with type IA glycogen storage disease (GSD) and one patient with type IB GSD. Blood glucose concentrations were determined at 30-min intervals during each tolerance test; blood lactate, blood insulin, and expiratory hydrogen were determined at 60-min intervals. The glucose levels remained in the normal range (L1.8 mM) during approximately 6.5-9.0 h, 3.5-6.5 h, and 2.25-4.0 h during the three tolerance tests, respectively. The lactate levels differed markedly for the different tests per patient, and for the same type of test between the patients. Blood insulin concentrations after starch administration did not exceed values of 50 mU/liter above fasting levels and were markedly lower than those after glucose administration (maximum levels of 280 mU/liter). The expiratory hydrogen excretion did not increase or only slightly increased after cornstarch administration (~2 0 ppm).
Abbreviations
GSD, glycogen storage disease GDF, gastric drip feedingPatients with deficiency of glucose-6-phosphatase (GSD IA) and glucose-6-phosphate translocase (GSD IB) cannot produce glucose from glycogen stores or by gluconeogenesis because of their functional absence of glucose-6-phosphatase activity (14). Plasma glucose concentrations therefore completely depend on exogenous sources. The primary aim of treatment is prevention of hypoglycemia. Since the introduction of continuous gastric drip feeding (I), many pediatricians have treated their type I patients with overnight GDF and frequent daytime feeding, resulting in catch-up growth, decrease of hepatomegaly, and improvement of biochemical abnormalities (7,8, 1 1, 12). Despite these good results, some major problems remain during longterm treatment. Nocturnal GDF, especially with a glucose amount over 8 mg/kg/min, renders these patients very carbohydrate-dependent and severe symptoms of hypoglycemia may occur at blood glucose concentrations which have previously been well tolerated (18). Such carbohydrate dependency may occur also at lower glucose quantities administered as kg/min, though less severely. For some patients and their parents, nocturnal GDF may be too complicated. The positioning of the Received July 27. 1983: accepted February 7, 1984 Correspondence may be addressed to G. P. A. Smit, Department of Pediatrics, University Hospital. 59 Oostersingel. 97 13 EZ Groningen. The Netherlands. Vol. 18, No. 9, 1984 Printed in U. S.A. gastric tube through the nose may ultimately cause imtation of the mucous membrane, nose bleeding, and nose and ear infections. The present studies were therefore undertaken to explore whether the use of slow release carbohydrate would decrease the carbohydrate dependency of the patient and whether its substitution for GDF would be feasible.
PATIENTS AND METHODSEight patients with biopsy-documented glucose-6-phosphatase deficiency (GSD IA) and one patient with g...
