Insulin receptors in developing rat liver: Acquisition of down regulation in the immediate postnatal period

1. The activities of some enzymes involved in both the utilization of glucose (pyruvate kinase, ATP citrate lyase, NADP-specific malate dehydrogenase, glucose 6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase and NADP-specific isocitrate dehydrogenase, all present in the supernatant fraction of liver homogenates) and the formation of glucose by gluconeogenesis (glucose 6-phosphatase in the whole homogenate and fructose 1,6-diphosphatase, phosphopyruvate carboxylase, NAD-specific malate dehydrogenase and fumarase in the supernatant fraction) have been determined in rat liver around birth and in the postnatal period until the end of weaning. 2. The activities of those enzymes involved in the conversion of glucose into lipid are low during the neonatal period and increase with weaning. NADP-specific malate dehydrogenase first appears and develops at the beginning of the weaning period. 3. The marked increase in cytoplasmic phosphopyruvate carboxylase activity at birth is probably the major factor initiating gluconeogenesis at that time. 4. The results are discussed against the known changes in dietary supplies and the known metabolic patterns during the period of development.

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Insulin Receptors in Developing Rat Liver

Neonatology ◽

10.1159/000243272 ◽

1990 ◽

Vol 58 (4) ◽

pp. 227-235 ◽

Cited By ~ 8

Author(s):

Ronald N. Margolis ◽

Keith Tanner ◽

Daniela Seminara ◽

Simeon I. Taylor

Keyword(s):

Rat Liver ◽

Insulin Receptors ◽

Developing Rat

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Ligand-induced translocation of insulin receptors in intact rat liver.

Journal of Biological Chemistry ◽

10.1016/s0021-9258(18)33903-6 ◽

1982 ◽

Vol 257 (18) ◽

pp. 10852-10860 ◽

Cited By ~ 8

Author(s):

B Desbuquois ◽

S Lopez ◽

H Burlet

Keyword(s):

Rat Liver ◽

Insulin Receptors

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Up-regulation of the multidrug resistance genes,Mrp1andMdr1b, and down-regulation of the organic anion transporter, Mrp2, and the bile salt transporter, Spgp, in endotoxemic rat liver

Hepatology ◽

10.1002/hep.510280625 ◽

1998 ◽

Vol 28 (6) ◽

pp. 1637-1644 ◽

Cited By ~ 270

Author(s):

Thera A. Vos ◽

Guido J. Hooiveld ◽

Hans Koning ◽

Sarah Childs ◽

Dirk K. Meijer ◽

...

Keyword(s):

Multidrug Resistance ◽

Bile Salt ◽

Rat Liver ◽

Resistance Genes ◽

Organic Anion ◽

Organic Anion Transporter ◽

Down Regulation ◽

Anion Transporter ◽

Multidrug Resistance Genes

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Developmental aspects of the lysosomal apparatus. Membrane affinity of N-acetyl-β-d-glucosaminidase in developing rat liver

Mechanisms of Ageing and Development ◽

10.1016/0047-6374(87)90014-5 ◽

1987 ◽

Vol 40 (2) ◽

pp. 149-156 ◽

Cited By ~ 3

Author(s):

Miguel A. Sosa ◽

Francisco Bertini

Keyword(s):

Rat Liver ◽

Membrane Affinity ◽

Developing Rat

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Down-regulation and recycling of insulin receptors. Effect of monensin on IM-9 lymphocytes and U-937 monocyte-like cells.

Journal of Biological Chemistry ◽

10.1016/s0021-9258(18)89876-3 ◽

1984 ◽

Vol 259 (22) ◽

pp. 14190-14195 ◽

Cited By ~ 1

Author(s):

J L Carpentier ◽

J M Dayer ◽

U Lang ◽

R Silverman ◽

L Orci ◽

...

Keyword(s):

Insulin Receptors ◽

Down Regulation

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Activation of 3-hydroxy-3-methylglutaryl-coenzyme A reductase in homogenates of developing rat brain

Biochemical Journal ◽

10.1042/bj1820367 ◽

1979 ◽

Vol 182 (2) ◽

pp. 367-370 ◽

Cited By ~ 15

Author(s):

W A Maltese ◽

J J Volpe

Keyword(s):

Rat Brain ◽

Cholesterol Synthesis ◽

Specific Activity ◽

Postnatal Period ◽

Developing Brain ◽

Brain Maturation ◽

Assay Mixture ◽

Coa Reductase ◽

Developing Rat ◽

Homogenization Medium

The specific activity of 3-hydroxy-3-methylglutaryl-CoA reductase increases when homogenates of developing rat brain are incubated at 37 degrees C or kept on ice. This increase is completely blocked by the addition of F- to the homogenization medium and the assay mixture. The capacity for activation of the reductase is greatest during the early postnatal period and declines as brain maturation proceeds. The data suggest that catalytic modification of the reductase may play a role in the regulation of cholesterol synthesis in the developing brain.

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