Augmentation of glucose and amino acid uptake by insulin in the developing rat diaphragm

Fricke, Robert F.; Cm, Clark

doi:10.1152/ajplegacy.1973.224.1.117

Cited by 22 publications

(10 citation statements)

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“…2 ) Our present experiment also showed that rat diaphragms from 22-day fetuses were sensitive to insulin in regard to glucose uptake and glycogenesis in vitro. The incorporation of labeled glucose into diaphragmatic glycogen was fully stimulated by 24 pU jml of insulin, which is well below the concentration found in fetal serum (Fig.…”

Section: Discussionsupporting

confidence: 76%

“…2 ) Significant decreases in the uptake of deoxyglucose also occurred from birth to the 22nd neonatal day in this study. This decline was caused by a decrease in V maX ' Similarly, other studies have demonstrated this decline in glucose uptake during development.…”

Section: Discussionsupporting

confidence: 63%

“…Robert et al demonstrated insulin-sensitive glucose uptake in 20th day fetal rat diaphragm. 2 ) The role of insulin in the fetal carbohydrate metabolism is still uncertain.…”

mentioning

confidence: 99%

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Muscle Response to Insulin in Fetuses of Diabetic Pregnant Rats

Wako

Kimura

1984

Agricultural and Biological Chemistry

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Section: Discussionsupporting

confidence: 76%

Section: Discussionsupporting

confidence: 63%

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Muscle Response to Insulin in Fetuses of Diabetic Pregnant Rats

Wako

Kimura

1984

Agricultural and Biological Chemistry

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“…Active accumulation of sugars has not been previously demonstrated in newborn rat kidney cortical slice (2,16,17), although neonatal rat diaphragm (7) and small intestine (6) have been shown to concentiate various hexoses. A recent report (13), however, has shown that the isolated proximal tubule fragment from newborn Sprague-Dawley rat kidney is capable of concentrative uptake of AMG.…”

Section: Discussionmentioning

confidence: 88%

The Ontogeny of Sugar Transport in Kidney

1978

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SummaryConcentrative uptake of a-methyl-D-glucoside (AMG) by isolated renal tubule fragments from the newborn Sprague-Dawley rat has been demonstrated and the validity of this phenomenon confirmed by an in vivo demonstration of AMG uptake by the newborn kidney cortex. A kinetic analysis of the entry phenomenon in the newborn tubule reveals the presence of two distinct membrane transport systems for AMG, only one of which is present in the adult tubule. All transport of sugar in both newborn and adult tubules was phlorizin-sensitive, but was only partially inhibited in Na+-free buffer. Glucose was shown to inhibit uptake competitively on the shared, high capacity system. Uptake on the high a f f i t y system in the newborn represents 15-20% of the total at physiologic sugar concentrations. It is concluded that active sugar transport is a characteristic of the newborn rat kidney and that the isolated tubule preparation is a more accurate reflection of this phenomenon than is the renal cortical slice. SpeculationThe presence of a unique high affinity glucose transport system in newborn renal tubules in addition to the lower a f f i t y system also found in the adult enables the anatomically immature kidney to efficiently reclaim sugar from the glomerular fdtrate and, thus, to prevent loss of calorically valuable nutrients in the promotion of growth.Sugar transport by the renal tubule has been the subject of a vast number of investigations extending over many years (19). The results of in vitro studies sometimes have been difficult to correlate with the in vivo situation. An example of this is the transport of hexoses by newborn rat kidney. Investigations employing the renal cortical slice of newborn rat kidney failed to demonstrate either galactose accumulation (2) or AMG uptake (16,17). Both sugars are known to share the glucose transport system(s) in adult rat kidney. Although this lack of uptake in vitro might be expected to result in neonatal glycosuria in vivo, Segal et al. (15) were unable to detect glucose in bladder urine from newborn Sprague-Dawley rats. The mechanism by which the neonatal kidney removes hexoses from the glomerular ultrafiltrate (which would resolve these paradoxical observations) had been left unexamined until the recent demonstration of active uptake of AMG by isolated renal proximal tubule fragments prepared from newborn Sprague-Dawley rat (13). This study demonstrates the in vivo concentration of AMG by newborn renal cortex. This indication that the tubule preparation reflects the in vivo situation led to an examination of the entry kinetics for AMG transport in isolated newborn cortical tubules. The results of this work constitute the basis for this report. MATERIALS AND METHODS ANIMALSFemale Sprague-Dawley rats were obtained from Charles River (Wilmington, MA) at 14 days of gestation and housed separately until parturition. Pups were killed by decapitation within the first 72 hr of age. Adult male Sprague-Dawley rats, obtained from the same source and weighing 150-200 g, were used fo...

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“…In the present study we investigated whether insulin has similar effects on diaphragm muscle during fetal life. While this work was in progress Fricke and Clark (1973) reported that insulin augments the accumulation of amino acids in the fetal rat diaphragm.…”

Section: Introductionmentioning

confidence: 93%

Protein Synthesis and Amino Acid Accumulation during Development in the Rat: Dissociation of Diaphragm and Heart Muscle Sensitivity to Insulin

Asplund¹

1975

Horm Res

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Insulin is released into the circulation early during fetal life, but the physiological significance of the hormone in the fetus is still unclear. The present study was undertaken to evaluate the possible effects of insulin on the protein metabolism of skeletal and heart muscle during the perinatal period in the rat. When incubating hemidiaphragms in a bicarbonate buffer, 0.1 U/ml ox insulin failed to enhance the incorporation of leucine-4,5–³ H into muscle protein before birth and during the immediate neonatal period. From 3 days of age onwards a stimulatory effect of insulin on protein synthesis was constantly observed. While insulin thus was ineffective in promoting protein synthesis in hemidiaphragms before the third postnatal day, it significantly enhanced the synthesis in heart muscle at an earlier stage of development. Insulin stimulated the uptake of α-aminoisobutyric acid-1-¹⁴C into the diaphragm muscle during late fetal life as well as through the early neonatal period. The role of insulin in protein metabolism during fetal life may thus be limited to the augmentation of amino acid transport in skeletal and heart muscle and to a stimulatory effect on protein synthesis only in certain tissue(s), e.g. heart muscle.

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Augmentation of glucose and amino acid uptake by insulin in the developing rat diaphragm

Cited by 22 publications

References 0 publications

Muscle Response to Insulin in Fetuses of Diabetic Pregnant Rats

Muscle Response to Insulin in Fetuses of Diabetic Pregnant Rats

The Ontogeny of Sugar Transport in Kidney

Protein Synthesis and Amino Acid Accumulation during Development in the Rat: Dissociation of Diaphragm and Heart Muscle Sensitivity to Insulin

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