Serum-Insulin Response to Glucose and Aminoacids in the Premature Infant

Grasso, Sebastiano; Saporito, N; Messina, A; Reitano, G

doi:10.1016/s0140-6736(68)90954-9

Cited by 93 publications

(43 citation statements)

References 15 publications

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“…There was a decrease in the initial plasma insulin concentration after exogenous glucose administration in comparison to that noted in the term lambs and adult sheep to a similar exogenous infusion. This is unexplained but parallels the work of Grasso et al (6) who suggested that in the premature newborn exogenous glucose infusions producing plasma glucose concentrations of >250 mg/dl resulted in only slight elevations in the plasma insulin concentration within the first 24 hr of life. It is apparent that the initial delayed response of plasma insulin concentration was ultimately increased by the time of the turnover period so that plasma insulin concentration was not different from that found in term lamb by that time.…”

Section: Dlscusslonsupporting

confidence: 78%

Endogenous Posthepatic Insulin Secretion and Metabolic Clearance Rates in the Neonatal Lamb

et al. 1980

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SummaryTo confirm posthepatic insulin availability in the neonatal Posthepatic insulin availability has been evaluated by steadystate insulin turnover studies with 1311-insulin. Spontaneously delivered term (age 3.3 f 0.8 days) (mean S.E.) and prematurely delivered lambs (betamathasone treated at 132 days) (age, 1.1 f 0.2 days) were compared with 4-to 5-month-old sheep. After a 7-hr fast, animals received 0.45% saline or 5.7 mg/kg/min glucose (0.06 ml/kg/min) for dhr followed by the tracer insulin infusion for 110 min. Plasma glucose, insulin, and immunoprecipitable insulin were measured sequentially during the steady state. Endogenous posthepatic insulin secretion and metabolic clearance rates were derived. Neither endogenous posthepatic insulin secretion rates nor metabolic clearance rates were different among the three groups of animals when either 0.45% saline or 5.7 mg/kg/ min exogenous glucose infusions were compared. Secretory response of the pancreatic / 3 cell to continuous glucose infusion seems similar for the term and preterm lamb when compared to adult sheep. SpeculationSecretory capability of the pancreatic fl cell does not account for imprecise control of endogenous glucose production previously noted in a neonatal lamb model.We have previously shown that the neonatal lamb requires a 10-fold increase in peripheral plasma insulin concentration compared to a 3-fold increase in plasma insulin in the adult to significantly reduce endogenous glucose production (1). Although the ex~lanation for the develo~mental difference in elucose control &s not clear, we hypotAesized that hepatic &nsitivity to insulin in the neonate could explain the difference. Exogenous glucose infusion produced hyperglycemia with hyperinsulinemia, but we were unable to differentiate the effect of the latter from that of the former. These effects. however. were evaluated in a subsequent series of studies in which varying concentrations of glucose and insulin were infused to produce euglycemia and hyperinsulinemia (14). We suggested that irrespective of the plasma glucose concentration and the potential counterregulatory responses that might occur during prolonged glucose infusion, endogenous glucose production in the neonatal lamb is primarily controlled by insulin.Incremental changes in glucose concentration influence the pancreatic beta (/ 3) cell secretory response (4). In neither previous study were we able to evaluate pancreatic P cell secretory activity.We inferred from evaluation of plasma glucose and insulin concentrations during the analysis of endogenous glucose production that the pancreatic / 3 cell response to plasma glucose concentration was comparable for both term neonates and older adult animals. period, steady-siate i n d i n secretion studies w&e performed using 311-insulin as the tracer. Plasma glucose, insulin, and insulinspecific activity were determined. Endogenous posthepatic insulin secretion and metabolic clearance rates were derived in spontaneously delivered term, prematurely delivered betamethasonetrea...

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Section: Dlscusslonsupporting

confidence: 78%

Endogenous Posthepatic Insulin Secretion and Metabolic Clearance Rates in the Neonatal Lamb

et al. 1980

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“…The early infusion of amino acids in preterm infants appears to have altered glucose metabolism, increasing their need for glucose. Previous investigators (26,27) have shown that preterm infants infused i.v. with amino acids have greater serum insulin concentrations than those infused with glucose alone.…”

Section: Discussionmentioning

confidence: 95%

Effect of Intravenous Amino Acids on Protein Metabolism of Preterm Infants during the First Three Days of Life

1993

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“…If the high amino acid levels are to be implicated in islet cell function, it is difficult to account for the low fetal IRG Early Postnatal Hormones, Fuels, and Liver Metabolism warilh high amino acid levels, and rise in IRG while plasma amino acids fall in concentration. The relation between changes in plasma amino acids and IRI secretion would be more appropriate, since the newborn i-cell is responsive to these substances (67).…”

Section: Methodsmentioning

confidence: 99%

Fuels, Hormones, and Liver Metabolism at Term and during the Early Postnatal Period in the Rat

Girard¹,

Cuendet²,

Marliss³

et al. 1973

J. Clin. Invest.

371

238

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A B ST R A C T The metabolic response to the first fast experienced by all mammals has been studied in the newborn rat. Levels of fuels and hormones have been compared in the fetal and maternal circulations at term. Then, after cesarean section just before the normal time of birth, sequential changes in the same parameters were quantified during the first 16 h of the neonatal period. No caloric intake was permitted, and the newborns were maintained at 370C. Activities of three key hepatic enzymes involved in glucose production were estimated.Marked differences in maternal and fetal hormones and fuels were observed. Lower levels of glucose, free fatty acids, and glycerol but higher levels of lactate, a-amino nitrogen, alanine, and glutamine were present in the fetus. Pyruvate, glutamate, and ketone bodies were not significantly different. The combination of a strikingly higher fetal immunoreactive insulin and a slightly lower immunoreactive glucagon (pancreatic) resulted in a profound elevation in the insulin-to-glucagon ratio, a finding consistent with an organism in an anabolic state.The rat at birth presents a body composition with respect to fuels available for mobilization and conversion which is dominated by carbohydrate and protein, since little fat is present. However, at birth a transient period of hypoglycemia occurred, associated with a rapid fall in insulin and rise in glucagon, causing reversal of the insulin-to-glucagon relationship toward ratios such as were observed in the mother. After a lag period, hepatic activities of phosphorylase, glucose-6-phosphatase, and phosphoenolpyruvate carboxykinase increased. Concurrent with these enzyme changes, the blood glucose returned to levels at or above those of the fetus. Interestingly, the fall observed in levels of the gluconeogenic precursors, lactate and amino acids, preceded the rise in enzyme activities and restoration of blood glucose. After 4 h, however, hypoglycemia recurred, during a period of decreasing hepatic glycogen content and blood lactate, pyruvate, and glycerol levels but of stable or increasing amino acid concentrations. Hepatic gluconeogenesis in this phase of depleted glycogen stores was insufficient to maintain euglycemia.Substrates derived from fat showed early changes of smaller magnitude. The rise in free fatty acids which occurred was less than twofold the value at birth, though this rise persisted up to 6 h. Whereas glycerol rose transiently, acetoacetate did not change and P-hydroxybutyrate concentration fell. Both ketone bodies showed a marked rise at 16 h, at a time of diminished free fatty acid levels. Plasma growth hormone, though higher in the fetal than the maternal circulation, showed no consistent change during the period of observation.The changes in levels of the endocrine pancreatic hormones at birth were appropriate in time, magnitude, and direction to be implicated as prime regulators of the metabolic response during the neonatal period in the rat.

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Serum-Insulin Response to Glucose and Aminoacids in the Premature Infant

Cited by 93 publications

References 15 publications

Endogenous Posthepatic Insulin Secretion and Metabolic Clearance Rates in the Neonatal Lamb

Endogenous Posthepatic Insulin Secretion and Metabolic Clearance Rates in the Neonatal Lamb

Effect of Intravenous Amino Acids on Protein Metabolism of Preterm Infants during the First Three Days of Life

Fuels, Hormones, and Liver Metabolism at Term and during the Early Postnatal Period in the Rat

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