The paradoxical growth hormone reaction after intravenous glucose in the newborn

Abstract

Abstract. Intravenous glucose tests (0.5 g/kg body weight) were performed in 13 newborn infants during their first 3 days of life. The variations in blood glucose, insulin and GH values were studied. In all patients there was a rise in plasma insulin. The correlation between initial insulin rise and glucose assimilation constant was 0.503 which is almost significant. The glucose load provoked a very variable response in plasma GH concentration, some infants showed a rise, others a fall. If the newborns were grouped according to this reaction it appeared that the GK response could be explained using Wilder's law of initial value. This hypothesis, however, did not stand up to a thorough statistical analysis including a discussion of a less well-known statistical error.In contrast to insulin secretion, GH apparently plays no major role in the short term regulation of the blood sugar in the newborn.Key words: Growth hormone --Newborn --Glucose load --Insulin. ExtractAn intravenous glucose load Jn 13 newborns showed a high glucose assimilation constant (k) of 4.81 j: 1.39. A positive correlation (r = 0.503) was found between k and the rise of insulin concentration within 2 min after injection of glucose. Plasma GH (growth hormone) concentrations varied widely with a high mean initial value (48.3 ng/ml), and no distinct pattern (neither a fall nor an increase) was provoced by glucose load. There was no correlation between variations of GH concentration and glucose assimilation. The present study suggests that the regulation of GIt secretion is not yet established in the early postnatal period. Therefore an increase in GIt concentration after glucose load is a coincidence rather than a "paradoxical" reaction. SpeculationRegulation of GH secretion based on negative correlation between blood glucose and GH concentration becomes effective only in the late 64 P.W. Nars et al.neonatal period. Because the mean levels of GH concentration are very high in the early postnatal period variations in GH concentrations do not affect glucose assimilation.