Regulation of Enzyme Development for Glycerol Utilization by Neonatal Rat Liver

Ward, Jane L.; Walker, Deryck G.

doi:10.1159/000240621

Cited by 6 publications

(4 citation statements)

References 21 publications

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“…In addition, this increase was correlated with the increase in glycerol kinase activity. Similar observations of an increase in enzymes of glycerol metabolism in the liver after birth were reported by other investigators (36,37). Quantitatively, in the 0-to 4-d-old newborn dogs, Hall et al (38) reported that approximately 50% of glycerol carbon was converted to glucose, accounting for 14% of glucose carbon.…”

Section: Discussionsupporting

confidence: 77%

Glycerol Metabolism and Triglyceride-Fatty Acid Cycling in the Human Newborn: Effect of Maternal Diabetes and Intrauterine Growth Retardation

Patel

Kalhan

1992

Pediatr Res

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ABSTRACT. Kinetics of glycerol metabolism and triglyceridelfatty acid cycling were quantified in 12 healthy, normal, appropriate-for-gestational-age (AGA) infants, eight small-for-gestational-age (SGA) infants, and five infants of insulin-dependent diabetic mothers (IDM) at less than 48 h of age. Stable isotope-labeled [2-13C]glycerol and [6,6-ZHz]glucose in combination with indirect respiratory calorimetry were used. The tracers were used as constant rate infusion and steady state isotopic enrichment of glucose, glycerol, and bicarbonate was measured by mass spectrometric methods. After a 7-to 9-h fast, the plasma glucose, glycerol, and FFA concentrations were similar in the AGA and IDM groups. In the SGA group, the plasma glucose concentration was significantly lower than that in the AGA group throughout the study, but plasma FFA and glycerol concentrations were not different from those in the AGA infants. Plasma betahydroxybutyrate concentration was significantly elevated in the AGA group compared with IDM and SGA infants (AGA 0.59 -1-0.39, SGA 0.35 + 0.09, IDM 0.33 + 0.21 mmol/L; mean f SD). The rate of appearance of glycerol was significantly elevated (p < 0.05) in SGA infants (AGA 9.47 + 2.11, IDM 9.55 + 2.14, SGA 12.15 + 3.87 pmol/kg.min). Between 80 and 90% of glycerol turnover was converted to glucose, accounting for 20% of glucose turnover with no significant difference in the three groups. Approximately 35% of glycerol carbon was recovered in the bicarbonate (COz) pool. Less than 5% of C 0 2 carbon was derived from glycerol. Estimation of triglyceride-fatty acid cycle revealed that the triglyceride energy mobilized was increased in SGA infants. Only 22-24% of the triglyceride energy released was oxidized to COz in the newborn infants; the majority (76-78%) was recycled back to the adipose tissue. These data show that lipolysis is active in the immediate neonatal period. The contribution of fat to oxidative metabolism is increased in SGA infants. The major metabolic fate of glycerol in the neonate is conversion to glucose, and glycerol is a minor contributor to oxidative metabolism. (Pediatr Res 31: [52][53][54][55][56][57][58] 1992)

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Section: Discussionsupporting

confidence: 77%

Glycerol Metabolism and Triglyceride-Fatty Acid Cycling in the Human Newborn: Effect of Maternal Diabetes and Intrauterine Growth Retardation

Patel

Kalhan

1992

Pediatr Res

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“…Mixing experiments showed that the low fetal activities were probably not due to an inhibitor. The rise in cGPDH in early extrauterine life is compa rable to that previously reported for rats [30], where the enzyme is apparently under hormonal control [32], To begin an investi gation of the possibility of different fetal and adult forms of cGPDH, we analyzed the kinetic properties of the enzyme in both of its catalytic directions. Our data (table IV) were similar to those reported for adult beef [7] and human [10] liver and showed no dif ference between the fetal and infant activi ties.…”

Section: Discussionsupporting

confidence: 52%

“…In the rat fetus, glycerol metabolism in creases late in gestation and during the first weeks of extrauterine life [30,32]. These increases are correlated with increases in the activities of liver GK and cGPDH [24,30], possibly stimulated by thyroid hormones [18,32].…”

Section: Introductionmentioning

confidence: 99%

“…These increases are correlated with increases in the activities of liver GK and cGPDH [24,30], possibly stimulated by thyroid hormones [18,32]. There has been one report of the detection of GK in human liver from prema ture newborns [19], To our knowledge there have been no reports of the ontogenetic de velopment of the three glycerol-metabolizing enzymes in the human fetus.…”

Section: Introductionmentioning

confidence: 99%

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Development of Enzymes of Glycerol Metabolism in Human Fetal Liver

et al. 1987

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The activities of three key enzymes of glycerol metabolism were measured in liver samples from 37 human fetuses ranging in gestational age from 18 weeks to term, from neonates (1–3 days) and from infants to 2 years. Glycerol kinase specific activity was constant throughout the period of fetal development examined, and was comparable to that measured in neonates and infants. owever, the subcellular distribution of the activity changed markedly, being predominantly particulate in fetal samples and cytoplasmic in postnatal samples. The particulate activity had an elevated K_m for glycerol. Cytoplasmic glycerol-3-phosphate dehydrogenase activity was very low in the fetal period, and then rose to adult levels during infancy. There were no kinetic differences between the fetal and postnatal activities. Mitochondrial glycerol-3-phosphate dehydrogenase activity rose somewhat after birth to near adult levels. The data indicate that glycerol can be metabolized by human fetal, neonatal and infant liver.

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