scholarly journals Hypophysectomy does not alter the acinar zonation of gluconeogenesis or the mitochondrial redox state in rat liver

1989 ◽  
Vol 260 (1) ◽  
pp. 183-187 ◽  
Author(s):  
D Tosh ◽  
K G M M Alberti ◽  
L Agius

The biochemical and functional heterogeneity of hepatocytes in different zones of the liver acinus may be related to the concentrations of hormones within the liver acinus. We examined the effects of hypophysectomy, which causes marked changes in plasma hormone levels and in activities of hepatic enzymes that are normally heterogeneously distributed, on the degree of metabolic zonation within the liver acinus. In hypophysectomized rats the activity of alanine aminotransferase was increased, but its normal zonation (predominance in the periportal zone) was preserved. The activity in cultured periportal and perivenous hepatocytes was increased by dexamethasone, but not by glucagon. Periportal hepatocytes from hypophysectomized rats expressed higher rates of gluconeogenesis in culture than did perivenous hepatocytes, irrespective of the absence or presence of dexamethasone, glucagon or insulin. Similar differences in rates of ketogenesis and in the mitochondrial redox state in response to glucagon were observed between periportal and perivenous hepatocytes from hypophysectomized rats as between cell populations from normal rats. Although hypophysectomy causes marked changes in hepatic enzyme activities, it does not alter the degree of zonation of alanine aminotransferase, gluconeogenesis or the mitochondrial redox state within the liver acinus.

Author(s):  
Vahid Ghanbarinejad ◽  
Mohammad M. Ommati ◽  
Zhipeng Jia ◽  
Omid Farshad ◽  
Akram Jamshidzadeh ◽  
...  

1993 ◽  
Vol 294 (3) ◽  
pp. 865-872 ◽  
Author(s):  
C Soler ◽  
M Soley

Most reports on the effects of epidermal growth factor (EGF) on gluconeogenesis have indicated that such effects depend on the substrate used and are only observable after a lag time of 30-40 min. Recently, an immediate and transient effect of EGF on glucose synthesis was described in a perfused liver system. Here we extend the study of the effect of EGF on gluconeogenesis to isolated hepatocytes from fasted rats. The delayed effect of EGF on gluconeogenesis was studied by adding the substrate 40 min after the peptide. Under these conditions EGF increased glucose synthesis from pyruvate, decreased it when the substrate was lactate or glycerol and did not modify gluconeogensis from fructose or dihydroxyacetone. EGF did not affect the metabolic flux through glycolysis, determined as the production of lactate+pyruvate from 30 mM glucose. Furthermore, EGF did not modify the metabolic flux through pyruvate kinase, determined as the production of lactate+pyruvate from 1 mM dihydroxyacetone. The differing effects of EGF on gluconeogenesis depending on the substrate used can be explained by the effects of EGF on the cytosolic redox state (measured as the lactate/pyruvate ratio). About 20 min after the addition of EGF, the mitochondrial redox state (measured as the 3-hydroxybutyrate/acetoacetate ratio) decreased. This effect of EGF was blocked by ammonium, which also abolished the effect of the peptide on gluconeogenesis. Thus the effect of EGF at the mitochondrial level appears to be necessary for its effects on gluconeogenesis. Taken together, our results indicate that the delayed effects of EGF on gluconeogenesis are secondary to the effects of the peptide at both the mitochondrial and cytosolic levels. In addition to these delayed effects, we observed that EGF rapidly and transiently stimulated glucose synthesis from lactate, decreased the cytosolic redox state and increased oxygen consumption. All of these rapid effects required the presence of extracellular calcium and disappeared in the presence of rotenone, suggesting that this rapid effect of EGF on gluconeogenesis is secondary to the stimulation of mitochondrial respiration.


2008 ◽  
Vol 38 (9) ◽  
pp. 2419-2425 ◽  
Author(s):  
Patrizia Castellani ◽  
Giovanna Angelini ◽  
Laura Delfino ◽  
Andrea Matucci ◽  
Anna Rubartelli

2012 ◽  
Vol 1817 ◽  
pp. S86-S87
Author(s):  
Umberto De Marchi ◽  
Jaime Santo-Domingo ◽  
Israel Sekler ◽  
Andreas Wiederkehr ◽  
Nicolas Demaurex

MethodsX ◽  
2018 ◽  
Vol 5 ◽  
pp. 1473-1483 ◽  
Author(s):  
Alex J. Wadley ◽  
Rhys G. Morgan ◽  
Kate J. Heesom ◽  
Paul S. Hole ◽  
Steven J. Coles

2011 ◽  
Vol 04 (03) ◽  
pp. 279-288 ◽  
Author(s):  
HE N. XU ◽  
RUSSELL C. ADDIS ◽  
DAVIDA F. GOINGS ◽  
SHOKO NIOKA ◽  
BRITTON CHANCE ◽  
...  

Redox state mediates embryonic stem cell (ESC) differentiation and thus offers an important complementary approach to understanding the pluripotency of stem cells. NADH redox ratio (NADH/(Fp + NADH)), where NADH is the reduced form of nicotinamide adenine dinucleotide and Fp is the oxidized flavoproteins, has been established as a sensitive indicator of mitochondrial redox state. In this paper, we report our redox imaging data on the mitochondrial redox state of mouse ESC (mESC) colonies and the implications thereof. The low-temperature NADH/Fp redox scanner was employed to image mESC colonies grown on a feeder layer of gamma-irradiated mouse embryonic fibroblasts (MEFs) on glass cover slips. The result showed significant heterogeneity in the mitochondrial redox state within individual mESC colonies (size: ~200–440 μm), exhibiting a core with a more reduced state than the periphery. This more reduced state positively correlates with the expression pattern of Oct4, a well-established marker of pluripotency. Our observation is the first to show the heterogeneity in the mitochondrial redox state within a mESC colony, suggesting that mitochondrial redox state should be further investigated as a potential new biomarker for the stemness of embryonic stem cells.


2018 ◽  
Vol 79 (4) ◽  
pp. 1862-1869 ◽  
Author(s):  
Cornelius Morze ◽  
Michael A. Ohliger ◽  
Irene Marco‐Rius ◽  
David M. Wilson ◽  
Robert R. Flavell ◽  
...  

Shock ◽  
1995 ◽  
Vol 4 (Supplement) ◽  
pp. 18
Author(s):  
Hiroaki KITADE ◽  
Kazushige SAKITANI ◽  
Yoshifumi HIRAMATSU ◽  
Yasuo KAMIYAMA ◽  
Seiji ITO ◽  
...  

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