1
|
Vollmer C, Nommensen J, Watolla M, Bauer I, Picker O. Influence of thoracic epidural anesthesia on gastric oxygenation during hypothermia and hemorrhage. Auton Neurosci 2016; 195:1-7. [PMID: 26905213 DOI: 10.1016/j.autneu.2016.01.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2015] [Revised: 01/26/2016] [Accepted: 01/27/2016] [Indexed: 11/30/2022]
Abstract
OBJECTIVE Hypothermia preserves gastric mucosal microvascular oxygenation (μHbO2) during hemorrhagic shock. Additionally, hypothermia activates the sympathetic nervous system that leads to the release of vasopressin. The aim of this study was to evaluate whether the effect of hypothermia is mediated via the sympathetic nervous system and/or via vasopressin. METHODS In prospective and randomized experiments on five anesthetized dogs (foxhounds, cross-over design, 6 groups with n=5 per group) we analyzed the effects of hemorrhage on μHbO2 during mild hypothermia (HT, 34 °C), during additional thoracic epidural anesthesia (HT/TEA) and during additional vasopressin V1 receptor blockade (HT/VB). As control groups, effects of hemorrhage were studied under normothermia alone (NT), during additional thoracic epidural anesthesia (NT/TEA) and during additional vasopressin V1 receptor blockade (NT/VB). RESULTS Hemorrhage decreased μHbO2 from 81 ± 3 to 49 ± 8%. In contrast, in the presence of hypothermia, μHbO2 was significantly higher during hemorrhagic shock (from 79 ± 3 to 66 ± 9%) despite a similar decrease in DO2. The effect of hypothermia on μHbO2 was reduced in the presence of thoracic epidural anesthesia or vasopressin receptor blockade. CONCLUSIONS Hypothermia preserves μHbO2 during hemorrhagic shock. This effect is partially abolished during thoracic epidural anesthesia or during vasopressin receptor blockade. The sympathetic nervous system and the vasopressin V1 receptor are partially involved in mediating the effect of hypothermia on gastric oxygenation during hemorrhage.
Collapse
Affiliation(s)
- Christian Vollmer
- Department of Anesthesiology, University Hospital Dusseldorf, Moorenstrasse 5, 40225 Dusseldorf, Germany.
| | - Jan Nommensen
- Department of Anesthesiology, University Hospital Dusseldorf, Moorenstrasse 5, 40225 Dusseldorf, Germany
| | - Markus Watolla
- Department of Anesthesiology, University Hospital Dusseldorf, Moorenstrasse 5, 40225 Dusseldorf, Germany
| | - Inge Bauer
- Department of Anesthesiology, University Hospital Dusseldorf, Moorenstrasse 5, 40225 Dusseldorf, Germany
| | - Olaf Picker
- Department of Anesthesiology, University Hospital Dusseldorf, Moorenstrasse 5, 40225 Dusseldorf, Germany
| |
Collapse
|
2
|
Bankir L, Roussel R, Bouby N. Protein- and diabetes-induced glomerular hyperfiltration: role of glucagon, vasopressin, and urea. Am J Physiol Renal Physiol 2015; 309:F2-23. [DOI: 10.1152/ajprenal.00614.2014] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Accepted: 04/13/2015] [Indexed: 12/21/2022] Open
Abstract
A single protein-rich meal (or an infusion of amino acids) is known to increase the glomerular filtration rate (GFR) for a few hours, a phenomenon known as “hyperfiltration.” It is important to understand the factors that initiate this upregulation because it becomes maladaptive in the long term. Several mediators and paracrine factors have been shown to participate in this upregulation, but they are not directly triggered by protein intake. Here, we explain how a rise in glucagon and in vasopressin secretion, directly induced by protein ingestion, might be the initial factors triggering the hepatic and renal events leading to an increase in the GFR. Their effects include metabolic actions in the liver and stimulation of sodium chloride reabsorption in the thick ascending limb. Glucagon is not only a glucoregulatory hormone. It is also important for the excretion of nitrogen end products by stimulating both urea synthesis in the liver (along with gluconeogenesis from amino acids) and urea excretion by the kidney. Vasopressin allows the concentration of nitrogenous end products (urea, ammonia, etc.) and other protein-associated wastes in a hyperosmotic urine, thus allowing a very significant water economy characteristic of all terrestrial mammals. No hyperfiltration occurs in the absence of one or the other hormone. Experimental results suggest that the combined actions of these two hormones, along with the complex intrarenal handling of urea, lead to alter the composition of the tubular fluid at the macula densa and to reduce the intensity of the signal activating the tubuloglomerular feedback control of GFR, thus allowing GFR to raise. Altogether, glucagon, vasopressin, and urea contribute to set up the best compromise between efficient urea excretion and water economy.
Collapse
Affiliation(s)
- Lise Bankir
- INSERM UMRS 1138, Centre de Recherche des Cordeliers, Paris, France
- Université Paris Diderot, Sorbonne-Paris-Cité, Paris, France; and
| | - Ronan Roussel
- INSERM UMRS 1138, Centre de Recherche des Cordeliers, Paris, France
- Université Paris Diderot, Sorbonne-Paris-Cité, Paris, France; and
- Diabétologie Endocrinologie Nutrition, DHU FIRE, Hôpital Bichat, AP-HP, Paris, France
| | - Nadine Bouby
- INSERM UMRS 1138, Centre de Recherche des Cordeliers, Paris, France
- Université Paris Diderot, Sorbonne-Paris-Cité, Paris, France; and
| |
Collapse
|
3
|
Hasselblatt M, Krampe H, Jacobs S, Sindram H, Armstrong VW, Hecker M, Ehrenreich H. Arginine challenge unravels persistent disturbances of urea cycle and gluconeogenesis in abstinent alcoholics. Alcohol Alcohol 2006; 41:372-8. [PMID: 16687468 DOI: 10.1093/alcalc/agl032] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
AIMS Data on recovery from hormonal and metabolic sequelae of alcoholism in strictly controlled alcohol abstinence are mainly restricted to short-term abstention. Our previous findings of persistently decreased plasma and urinary urea concentrations in long-term abstinent alcoholics prompted us to further elucidate this unexplained phenomenon. METHODS The response of circulating urea cycle metabolites and glucose-regulating hormones to an intravenous load (30 g) of arginine hydrochloride was investigated in abstinent male alcoholics (n = 14) after complete recovery of all routine liver parameters and compared with that in healthy male controls (n = 15). RESULTS The arginine challenge provoked (i) higher peak concentrations of arginine and increased arginine/ornithine and ornithine/citrulline ratios in the plasma of abstinent alcoholics; (ii) augmented plasma glutamine concentrations in alcoholics in the presence of comparable levels in both experimental groups of plasma glutamate, ammonia, and nitrate/nitrite; (iii) parallel increases in plasma urea concentrations over the respective baseline levels but distinctly higher urinary urea excretion in controls; (iv) a blunted blood glucose response to arginine in alcoholics together with a reduced insulin and glucagon surge; and (v) an elevated growth hormone peak as compared with controls. CONCLUSIONS Application of an intravenous arginine challenge reveals profound and lasting metabolic and hormonal disturbances in abstinent alcoholics, affecting urea cycle and gluconeogenesis. The common denominator of many of these changes may be an acquired irreversible deficiency in cellular energy regulation.
Collapse
Affiliation(s)
- Martin Hasselblatt
- Division of Clinical Neuroscience, Max-Planck-Institute of Experimental Medicine, Göttingen, Germany
| | | | | | | | | | | | | |
Collapse
|
4
|
Riveros-Rosas H, Zentella de Piña M, Guinzberg R, Saldaña-Balmori Y, Julián-Sánchez A, Saavedra-Molina A, Piña E. Antagonism between the metabolic responses induced by epinephrine and piroxicam on isolated rat hepatocytes. Eur J Pharmacol 1999; 380:49-59. [PMID: 10513559 DOI: 10.1016/s0014-2999(99)00521-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Nonsteroidal anti-inflammatory drugs (NSAIDs) are one of the most employed therapeutic agents. They have a wide spectrum of biological effects, some of which are independent of cyclooxygenase inhibition, such as the alterations on the components of signal transduction systems. In particular, previous data from our laboratory suggested an antagonism between epinephrine and piroxicam, one of the most prescribed NSAIDs. Thus, this study deals with the epinephrine-piroxicam antagonism recorded for metabolic responses in isolated rat hepatocytes. The obtained results show that epinephrine stimulates lactate and ethanol consumption, stimulates glucose release from lactate only, and has no effect on cellular triacylglycerides content. Otherwise, in a dose-dependent basis, piroxicam stimulates lactate and ethanol consumption accompanied by an increase in triacylglycerides content, without changes in glucose release by hepatocytes. Piroxicam blocks the epinephrine-induced stimulation of glucose release from lactate, and epinephrine blocks the piroxicam-mediated increase in triacylglycerides content from lactate or ethanol. In contrast, the effects of epinephrine and piroxicam, promoting the consumption of lactate and ethanol, are not antagonized or added after the simultaneous administration of both compounds. This last result is probably related to the ability of both compounds to stimulate oxygen consumption. On isolated rat liver mitochondria, micromolar doses of piroxicam partially uncouple oxidative phosphorylation, and paradoxically stimulates an ATP-dependent mitochondrial function as citrullinogenesis. These results show for first time, on isolated rat hepatocytes, an antagonism between the metabolic responses of epinephrine and piroxicam, at the concentration found in plasma after its therapeutical administration.
Collapse
Affiliation(s)
- H Riveros-Rosas
- Departamento de Bioquímica, Facultad de Medicina, Universidad Nacional Autónoma de México, México, DF.
| | | | | | | | | | | | | |
Collapse
|
5
|
Saavedra-Molina A, Devlin TM. Effect of extra- and intra-mitochondrial calcium on citrulline synthesis. Amino Acids 1997. [DOI: 10.1007/bf01373009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
|
6
|
Mommsen TP, Danulat E, Walsh PJ. Hormonal regulation of metabolism in hepatocytes of the ureogenic teleostopsanus beta. FISH PHYSIOLOGY AND BIOCHEMISTRY 1991; 9:247-252. [PMID: 24213715 DOI: 10.1007/bf02265145] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 11/27/1990] [Indexed: 06/02/2023]
Abstract
Short-term exposure of isolated toadfish hepatocytes to high concentrations (100 nM) of glucagon, glucagon-like peptide (GLP) or epinephrine significantly increases the rate of lactate gluconeogenesis (1.3-fold) and glycogenolysis (5- to 7-fold). Half-maximal responsiveness to GLP is reached at about 2 nM for gluconeogenesis and 6 nM for glycogenolysis, while the value for glycogenolysis activated by catfish glucagon is 28 nM. Cells do not to respond to 5 nM epinephrine. Norepinephrine, urotensin II and leucine-enkephalin, each applied at 100 nM, increase the rate of glycogenolysis by 1.3 to 1.5-fold. All other hormones tested (vasotocin, isotocin, VIP, methionine-enkephalin, ovine prolactin, β-endorphin, APY, salmon insulin) failed to affect metabolic flux through glycogenolysis or gluconeogenesis. None of the hormones altered the rate of urea synthesis or the rate of lactate oxidation by hepatocytes. Although toadfish hepatocytes are responsive to hormonal stimuli, they do not appear to be a useful model to study evolutionary trends in short-term hormonal regulation of urea synthesis. However, the obvious differences in mechanisms of control of urea synthesis in this species compared with ureogenic amphibians and mammals open an intriguing avenue for research.
Collapse
Affiliation(s)
- T P Mommsen
- Department of Biochemistry and Microbiology, University of Victoria, P.O. Box 3055, V8W 3P6, Victoria, B.C., Canada
| | | | | |
Collapse
|
7
|
Urea synthesis in fishes: evolutionary and biochemical perspectives. PHYLOGENETIC AND BIOCHEMICAL PERSPECTIVES 1991. [DOI: 10.1016/b978-0-444-89124-2.50010-5] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
|
8
|
Haüssinger D. Nitrogen metabolism in liver: structural and functional organization and physiological relevance. Biochem J 1990; 267:281-90. [PMID: 2185740 PMCID: PMC1131284 DOI: 10.1042/bj2670281] [Citation(s) in RCA: 227] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- D Haüssinger
- Medizinische Universitätsklinik, Freiburg, Federal Republic of Germany
| |
Collapse
|
9
|
Johnston JD, Brand MD. The mechanism of Ca2+ stimulation of citrulline and N-acetylglutamate synthesis by mitochondria. BIOCHIMICA ET BIOPHYSICA ACTA 1990; 1033:85-90. [PMID: 2105747 DOI: 10.1016/0304-4165(90)90198-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
ATP-driven citrulline synthesis by mitochondria treated with oligomycin, uncoupler and Ca2+ ionophore is stimulated more than 2-fold by an increase in extramitochondrial free [Ca2+] in the range 1-5 microM. Stimulation increases with the length of preincubation of mitochondria with Ca2+. EGTA prevents stimulation if added at the start of the preincubation period, but is without effect if added at the end, suggesting that Ca2+ acts indirectly on citrulline synthesis via the accumulation of an intermediate. Neither carbamoyl-phosphate synthase (ammonia) nor ornithine carbamoyltransferase are stimulated by up to 50 microM free Ca2+ in mitochondrial extracts, but N-acetylglutamate synthase is stimulated about 30% by 10 microM free Ca2+. We propose that an increase in the activity of N-acetylglutamate synthase in response to an increase in free [Ca2+] in the mitochondrial matrix may contribute to hormonal stimulation of the urea cycle.
Collapse
Affiliation(s)
- J D Johnston
- Department of Biochemistry, University of Cambridge, U.K
| | | |
Collapse
|
10
|
García-Sáinz JA, Macías-Silva M, Hernández-Sotomayor SM, Torres-Márquez ME, Trivedi D, Hruby VJ. Modulation of glucagon actions by phorbol myristate acetate in isolated hepatocytes. Effect of hypothyroidism. Cell Signal 1990; 2:235-43. [PMID: 2169291 DOI: 10.1016/0898-6568(90)90051-b] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Phorbol myristate acetate (PMA) inhibits glucagon-stimulated cyclic AMP accumulation and shifts to the right the dose-response curve to glucagon for ureagenesis. In cells from hypothyroid rats the effect of PMA on glucagon-stimulated ureagenesis was much more pronounced, but its effect on cyclic AMP accumulation was similar to that observed in the control cells. The stimulations of ureagenesis by the glucagon analogue THG and dibutyryl cyclic AMP (But2-cAMP) were also diminished by PMA, to a greater extent in cells from hypothyroid rats than in those from euthyroid rats. PMA inhibited the increases in cytoplasmic [Ca2+] induced by glucagon. THG or But2-cAMP; the effect of PMA was much more marked in cells from hypothyroid rats than in the controls. Treatment of the cells with glucagon or THG increased the production of citrulline by subsequently isolated mitochondria, whereas PMA diminished their effects. The results suggest that PMA alters glucagon actions at least at two levels; (i) cyclic AMP production and (ii) elevation of cytosol calcium. The increased sensitivity to PMA of some glucagon effects in hypothyroid rats seems to be related to the latter action.
Collapse
Affiliation(s)
- J A García-Sáinz
- Instituto de Fisiología Celular, Universidad Nacional Autónoma de México
| | | | | | | | | | | |
Collapse
|
11
|
Halestrap AP. The regulation of the matrix volume of mammalian mitochondria in vivo and in vitro and its role in the control of mitochondrial metabolism. BIOCHIMICA ET BIOPHYSICA ACTA 1989; 973:355-82. [PMID: 2647140 DOI: 10.1016/s0005-2728(89)80378-0] [Citation(s) in RCA: 369] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The purpose of this article is to describe briefly the methods by which the intra-mitochondrial volume may be measured both in vitro and in situ, to summarise the mechanisms thought to regulate the mitochondrial volume and then to review in more detail the evidence that changes in the intra-mitochondrial volume play an important part in the regulation of liver mitochondrial metabolism by glucogenic hormones such as glucagon, adrenaline and vasopressin. It will be shown that these hormones cause an increase in matrix volume sufficient to produce significant activation of fatty acid oxidation, respiration and ATP production, pyruvate carboxylation, citrulline synthesis and glutamine hydrolysis. These are all processes activated by such hormones in vivo. I will go on to demonstrate that the increase in matrix volume is brought about by an increase in mitochondrial [PPi]. This is able to stimulate K+ entry into the matrix, perhaps through an interaction with the adenine nucleotide translocase. The rise in matrix [PPi] is a consequence of an increase in cytosolic and hence mitochondrial [Ca2+] which inhibits mitochondrial pyrophosphatase. In the final section of the review I provide evidence that changes in mitochondrial volume may be important in the responses of a variety of tissues to hormones and other stimuli. I write as a metabolist with a working knowledge of bioenergetics rather than the converse, and this will certainly be reflected in the approach taken. If I cause offence to any dedicated experts in the field of bioenergetic by my ignorance or lack of understanding of their studies I can only offer my apologies and ask to be corrected.
Collapse
Affiliation(s)
- A P Halestrap
- Department of Biochemistry, University of Bristol, U.K
| |
Collapse
|
12
|
Johnston JD, Brand MD. Sub-micromolar concentrations of extramitochondrial Ca2+ stimulate the rate of citrulline synthesis by rat liver mitochondria. Biochem J 1989; 257:285-8. [PMID: 2920019 PMCID: PMC1135569 DOI: 10.1042/bj2570285] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
1. In the presence of physiological concentrations of Na+ and Mg2+, the rate of citrulline synthesis by isolated rat liver mitochondria respiring on a range of substrates was stimulated by up to 60% when the extramitochondrial Ca2+ concentration was raised from 130 pM to 770 nM. 2. Our findings suggest that hormonal stimulation of the urea cycle may be mediated by Ca2+.
Collapse
Affiliation(s)
- J D Johnston
- Department of Biochemistry, University of Cambridge, U.K
| | | |
Collapse
|
13
|
Zentella de Piña M, Villalobos-Molina R, Saavedra-Molina A, Riveros-Rosas H, Piña E. Effects of moderate chronic ethanol consumption on rat liver mitochondrial functions. Alcohol 1989; 6:3-7. [PMID: 2541737 DOI: 10.1016/0741-8329(89)90066-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The biochemical consequences of moderate chronic ethanol ingestion has been scarcely investigated in spite of the fact that most of the human population drinks ethanol on a moderate basis. This paper describes some metabolic effects produced by moderate ethanol consumption. The substitution of drinking water in rats for a 10% ethanol solution during 4 weeks resulted in: a) a decrease of blood urea and citrulline synthesis in liver mitochondria; b) a slight inhibition in state 3 and state 4 respiration either with glutamate-malate as substrates or succinate as substrate; c) no change in ADP/O ratio with succinate but slight increase with glutamate-malate; d) a reduction of the cytochrome oxidase activity and cytochromes a+a3 content; e) a 42% increase in the succinate dehydrogenase activity and a small but constant increase in the Vmax (no change in the Km) of the adenine nucleotide translocase activity in liver mitochondria. These results show that even moderate, but continuous ethanol ingestion, produces metabolic responses that must be carefully evaluated to define health risk in larger human groups.
Collapse
Affiliation(s)
- M Zentella de Piña
- Departamento de Bioquímica, Facultad de Medicina, Universidad Nacional Autónoma de México
| | | | | | | | | |
Collapse
|
14
|
Hernández-Sotomayor SM, García-Sáinz JA. Phorbol esters and calcium-mobilizing hormones increase membrane-associated protein kinase C activity in rat hepatocytes. BIOCHIMICA ET BIOPHYSICA ACTA 1988; 968:138-41. [PMID: 3377882 DOI: 10.1016/0167-4889(88)90053-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Vasopressin, angiotensin II, epinephrine (alpha 1-adrenergic action) and phorbol 12-myristate 13-acetate (PMA) induce increases in membrane-associated protein kinase C activity concomitant with decreases in the cytosolic activity. The data indicate that the calcium-mobilizing hormones and the active phorbol ester induce translocation from the cytosol to the plasma membrane of this protein kinase. The protein kinase C inhibitor, 1-(5-isoquinolinesulfonyl)-2-methylpiperazine, blocked the translocation to the membrane of this protein kinase induced by PMA and vasopressin.
Collapse
|
15
|
|
16
|
Guinzberg R, Laguna I, Zentella A, Guzman R, Piña E. Effect of adenosine and inosine on ureagenesis in hepatocytes. Biochem J 1987; 245:371-4. [PMID: 3663162 PMCID: PMC1148131 DOI: 10.1042/bj2450371] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Adenosine and inosine produced a dose-dependent stimulation of ureagenesis in isolated rat hepatocytes. Hypoxanthine, xanthine and uric acid were without effect. Half-maximally effective concentrations were 0.08 microM for adenosine and 5 microM for inosine. Activation of ureagenesis by both nucleosides had the following characteristics: (a) it was observed with either glutamine or (NH4)2CO3, provided that glucose was present; (b) it was not detected when glucose was replaced by lactate plus oleate; (c) it was mutually antagonized by glucagon, but not by adrenaline; and (d) it was dependent on Ca2+. We suggest that the action of adenosine and inosine on ureagenesis might be of physiological significance.
Collapse
Affiliation(s)
- R Guinzberg
- Departmento de Bioquimica, Facultad de Medicina, Universidad Nacional Autonoma de Mexico, D.F
| | | | | | | | | |
Collapse
|
17
|
García-Sáinz JA, Hernández-Sotomayor SM. Inhibitors of protein kinase C block the alpha 1-adrenergic refractoriness induced by phorbol 12-myristate 13-acetate, vasopressin and angiotensin II. EUROPEAN JOURNAL OF BIOCHEMISTRY 1987; 163:417-21. [PMID: 3028803 DOI: 10.1111/j.1432-1033.1987.tb10814.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Vasopressin and angiotensin II inhibited in a dose-dependent fashion the stimulation of ureagenesis induced by alpha 1-adrenergic activation in hepatocytes incubated in medium without calcium and containing 25 microM EGTA. Vasopressin was more potent than angiotensin II. The effect of different inhibitors of protein kinase C on the alpha 1-adrenergic blockade induced by the vasopressor peptides was tested. It was observed that N-(6-aminohexyl)-5-chloro-1-naphthalene sulfonamide (W-7), 4-aminoethyl-1-[2,3-bis(n-decloxyl)-n-propyl]-4-phenylpiperadin e dihydrochloride (CP-46,665-1); 8-(N,N-diethylamino)octyl-3,4, 5-trimethoxybenzoate (TMB-8), polymyxin B and 1-(5-isoquinolynsulfonyl)-2-methylpiperazine (H-7) block this effect of the vasopressor peptides in a dose-dependent fashion. The active phorbol ester, phorbol 12-myristate 13-acetate (PMA), also inhibited the alpha 1-adrenergic stimulation of ureagenesis in these cells. The inhibitors of protein kinase also blocked the effect of phorbol esters but a preincubation with the inhibitors before the addition of PMA was required. alpha 1-Adrenergic activation of phosphatidylinositol labeling was also abolished by PMA; the inhibitors of protein kinase partially blocked this effect of PMA. In summary, our data indicate that inhibitors of protein kinase C can block the alpha 1-adrenergic refractoriness induced by active phorbol esters, vasopressin and angiotensin II. The data are consistent with an important role of protein kinase C in modulating the alpha 1-adrenergic responsiveness of hepatocytes.
Collapse
|
18
|
García-Sáinz JA, Tussié-Luna MI, Hernández-Sotomayor SM. Phorbol esters, vasopressin and angiotensin II block alpha 1-adrenergic action in rat hepatocytes. Possible role of protein kinase C. BIOCHIMICA ET BIOPHYSICA ACTA 1986; 887:69-72. [PMID: 3011123 DOI: 10.1016/0167-4889(86)90123-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The effect of vasopressin, angiotensin II and phorbol myristate acetate on the alpha 1-adrenergic action (induced by epinephrine + propranolol), was studied. We selected three conditions: (a) ureagenesis in medium without added calcium and containing 25 microM EGTA; (b) ureagenesis using cells from hypothyroid animals, and (c) gluconeogenesis from dihydroxyacetone. Under these conditions epinephrine + propranolol produces clear metabolic effects, whereas the vasopressor peptides do not (although they stimulate phosphoinositide turnover). It was observed that the vasopressor peptides and the active phorbol ester inhibited in a concentration-dependent fashion the effect of epinephrine + propranolol. It is suggested that activation of protein kinase C by phorbol esters or physiological stimuli (hormones that activate phosphoinositide turnover, such as vasopressin or angiotensin II) modulate the hepatocyte alpha 1-adrenergic responsiveness.
Collapse
|
19
|
García-Sáinz JA, Contreras-Rodríguez JL. Possible existence of two mechanisms involved in alpha 1-adrenergic action: effect of Sgd 101/75. Eur J Pharmacol 1986; 125:103-10. [PMID: 2874037 DOI: 10.1016/0014-2999(86)90088-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The effect of 2-(2-methyl-indazol-4-imino)-imidazoline (Sgd 101/75) on the rate of urea synthesis by isolated rat hepatocytes was studied. This agent was observed to stimulate ureagenesis through the activation of alpha 1-adrenoceptors (prazosin-sensitive). The effect of Sgd 101/75 was dependent on the presence of calcium and was not affected by insulin. The active phorbol ester, phorbol 12-myristate 13-acetate, blocked the effect of Sgd 101/75. It was also observed that this adrenoceptor agonist was unable to stimulate ureagenesis in hepatocytes obtained from hypothyroid rats but produced clear stimulation of this metabolic pathway in cells obtained from adrenalectomized rats. The data indicate that this agonist stimulates hepatic metabolism through a calcium-dependent, insulin-insensitive pathway for alpha 1-adrenergic action, modulated by the thyroid status of the animal.
Collapse
|
20
|
|
21
|
Joseph SK, Coll KE, Thomas AP, Rubin R, Williamson JR. The role of extracellular Ca2+ in the response of the hepatocyte to Ca2+-dependent hormones. J Biol Chem 1985. [DOI: 10.1016/s0021-9258(17)38900-7] [Citation(s) in RCA: 66] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
|
22
|
García-Sáinz JA, Hernández-Sotomayor SM. Adrenergic regulation of gluconeogenesis: possible involvement of two mechanisms of signal transduction in alpha 1-adrenergic action. Proc Natl Acad Sci U S A 1985; 82:6727-30. [PMID: 2995981 PMCID: PMC390759 DOI: 10.1073/pnas.82.20.6727] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
We have previously suggested that the effects of alpha 1-adrenergic agents on hepatocyte metabolism involve two mechanisms: (i) a calcium-independent insulin-sensitive process that is modulated by glucocorticoids and (ii) a calcium-dependent insulin-insensitive process that is modulated by thyroid hormones. We have studied the effect of epinephrine (plus propranolol) on gluconeogenesis from lactate and dihydroxyacetone. It was observed that the adrenergic stimulation of gluconeogenesis from lactate seemed to occur through both mechanisms, whereas when the substrate was dihydroxyacetone the action took place exclusively through the calcium-independent insulin-sensitive process. This effect was absent in hepatocytes from adrenalectomized rats, suggesting that it is modulated by glucocorticoids.
Collapse
|
23
|
Martin AD, Titheradge MA. Stimulation of mitochondrial pyruvate metabolism and citrulline synthesis by dexamethasone. Effect of isolation and incubation media. Biochem J 1984; 222:379-87. [PMID: 6433898 PMCID: PMC1144189 DOI: 10.1042/bj2220379] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Hepatic mitochondria isolated in 0.3 M-sucrose or 0.3 M-mannitol from rats treated for 3h with dexamethasone displayed stimulated rates of pyruvate carboxylation and decarboxylation and citrulline synthesis when compared with organelles from control animals. Mitochondria isolated in mannitol also displayed elevated rates of pyruvate carboxylation and decarboxylation when compared with those isolated in sucrose, and this stimulation was shown to be independent of the lengthy isolation procedure. Citrulline synthesis proceeded at similar rates in mitochondria isolated in either sugar. The concentration of exchangeable adenine nucleotides was identical in mitochondria isolated in sucrose or mannitol, suggesting that those prepared in the former sugar are not more permeable to metabolites than those prepared in the latter. The matrix volume of mitochondria isolated in mannitol was greater than that of mitochondria isolated in sucrose, and the effect of mannitol on pyruvate metabolism was mimicked by swelling the organelles in hypo-osmotic sucrose. Measurements of the extra-matrix volume by using [14C]sucrose or [14C]mannitol suggest that mannitol can permeate mitochondria to a greater extent than can sucrose. The possibility that mannitol elicits its effect by entering the mitochondrial matrix and so initiating swelling is discussed.
Collapse
|
24
|
Corvera S, Huerta-Bahena J, Pelton JT, Hruby VJ, Trivedi D, García-Sáinz JA. Metabolic effects and cyclic AMP levels produced by glucagon, (1-N alpha-Trinitrophenylhistidine,12-homoarginine)glucagon and forskolin in isolated rat hepatocytes. BIOCHIMICA ET BIOPHYSICA ACTA 1984; 804:434-41. [PMID: 6087925 DOI: 10.1016/0167-4889(84)90071-5] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
[1-N alpha-Trinitrophenylhistidine,12-homoarginine]glucagon (THG) is a potent antagonist of the effects of glucagon on liver membrane adenylate cyclase. In isolated hepatocytes, this glucagon analogue was an extremely weak partial agonist for cAMP accumulation, and it blocked the stimulation of cAMP accumulation produced by glucagon. However, THG was a full agonist for the stimulation of glycogenolysis, gluconeogenesis and urea synthesis in rat hepatocytes, and did not antagonize the metabolic effects of glucagon under most of the conditions examined. Forskolin potentiated the stimulation of cAMP accumulation produced by glucagon or THG, but did not potentiate their metabolic actions. A much larger increase in cAMP levels seemed to be required for the stimulation of hepatocyte metabolism by forskolin than by glucagon or THG. This may suggest the existence of a functional compartmentation of cAMP in rat hepatocytes. The possible existence of compartments in cAMP-mediated hormone actions and the involvement of factors, besides cAMP, in mediating the effects of THG and glucagon is suggested.
Collapse
|
25
|
Corvera S, Hernandez-Sotomayor SM, Garcia-Sainz JA. Modulation by thyroid status of cyclic AMP-dependent and Ca2+-dependent mechanisms of hormone action in rat liver cells. Possible involvement of two different transduction mechanisms in alpha 1-adrenergic action. BIOCHIMICA ET BIOPHYSICA ACTA 1984; 803:95-105. [PMID: 6320911 DOI: 10.1016/0167-4889(84)90060-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The actions of hormones which are associated to cAMP-dependent and calcium-dependent mechanisms of signal transduction were studied in hepatocytes obtained from rats with different thyroid states. In cells from euthyroid and hyperthyroid rats, the metabolic actions of epinephrine were mediated mainly through alpha 1-adrenoceptors; beta-adrenoceptors seem to be functionally unimportant. In contrast, both alpha 1- and beta-adrenoceptors mediate the actions of epinephrine in hepatocytes from hypothyroid animals. Phosphatidylinositol labeling was strongly stimulated by epinephrine, vasopressin and angiotensin II in cells from eu-, hyper- or hypothyroid rats. However, metabolic responsiveness to vasopressin and angiotensin II was markedly impaired in the hypothyroid state. The glycogenolytic response to the calcium ionophore A-23187 was also impaired, suggesting that hepatocytes from hypothyroid rats are less sensitive to calcium signalling. The persistence of alpha 1-adrenergic responsiveness in the hypothyroid state suggests that the mechanism of signal transduction for alpha 1-adrenergic amines is not identical to that of the vasopressor peptides. alpha 1-Adrenergic stimulation of cyclic AMP accumulation was not detected in cells from hypothyroid rats. These data suggest that factors besides calcium and besides cAMP are probably involved in alpha 1-adrenergic actions. Metabolic responses to glucagon and to the cAMP analogue dibutyryl cAMP were not markedly changed during hypothyroidism, although cAMP accumulation produced by glucagon and beta-adrenergic agonists was enhanced. In hyperthyroidism, cell responsiveness to epinephrine, vasopressin, angiotensin II and glucagon was decreased, but sensitivity to cAMP was not markedly altered. The factors involved in this hyposensitivity to hormones during hyperthyroidism are unclear.
Collapse
|
26
|
Hernández-Sotomayor SM, García-Sáinz JA. Adrenergic regulation of ureogenesis in hepatocytes from adrenalectomized rats. Possible involvement of two pathways of signal transduction in alpha 1-adrenergic action. FEBS Lett 1984; 166:385-8. [PMID: 6319200 DOI: 10.1016/0014-5793(84)80118-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
In hepatocytes from control rats, the ureogenic action of epinephrine is mainly mediated through alpha 1-adrenoceptors and the effect is independent of the presence of extracellular calcium. In hepatocytes from adrenalectomized rats, both alpha 1- and beta-adrenoceptors are involved in the action of epinephrine. Furthermore, the alpha 1-adrenergic-mediated stimulation of ureogenesis in these cells is dependent on the presence of extracellular calcium. Our results indicate that glucocorticoids modulate the calcium dependency of alpha 1-adrenergic effects and are consistent with our suggestion that two pathways are involved in the transduction of the alpha 1-adrenergic signal.
Collapse
|
27
|
Pushpendran CK, Corvera S, García-Sáinz JA. Effect of insulin on alpha1-adrenergic actions in hepatocytes from euthyroid and hypothyroid rats. Possible involvement of two pathways in alpha1-adrenergic actions. Biochem Biophys Res Commun 1984; 118:451-9. [PMID: 6367738 DOI: 10.1016/0006-291x(84)91324-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The effect of insulin on the alpha1-adrenergic stimulation of glycogenolysis and ureogenesis, which is very small or undetectable in hepatocytes from control animals, is marked in hepatocytes from hypothyroid rats; the metabolic actions due to alpha1-adrenergic activation, but not those due to glucagon, were nearly blocked by insulin in cells from hypothyroid rats. The alpha1-adrenergic-mediated stimulation of phosphatidylinositol labelling was not affected by insulin in cells from either control or hypothyroid rats. The data suggest that the alpha1-adrenergic action proceeds through two pathways, one of which is very sensitive to insulin and predominates in cells from hypothyroid rats.
Collapse
|
28
|
Huerta-Bahena J, García-Saínz JA. Inositol administration restores the sensitivity of liver cells formed during liver regeneration to alpha 1-adrenergic amines, vasopressin and angiotensin II. BIOCHIMICA ET BIOPHYSICA ACTA 1983; 763:125-8. [PMID: 6412762 DOI: 10.1016/0167-4889(83)90035-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Hepatocytes obtained from rats partially hepatectomized 72 h before experimentation are insensitive to alpha 1-adrenergic amines, vasopressin, angiotensin II and ionophore A23187. However, if inositol is administered to the rats 24 and 48 h after surgery, the above-mentioned hormones stimulate glycogenolysis, gluconeogenesis and ureogenesis in the newly formed hepatocytes. Furthermore, ionophore A23187 is able to stimulate glycogenolysis in these cells, the mechanism through which inositol produces this effect being unknown. A rôle for phosphatidylinositol is suggested.
Collapse
|
29
|
Pushpendran CK, Corvera S, García-Sáinz JA. Effect of pertussis toxin on hormonal responsiveness of rat hepatocytes. FEBS Lett 1983; 160:198-202. [PMID: 6309562 DOI: 10.1016/0014-5793(83)80966-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The ureogenic action of epinephrine in hepatocytes from normal adult rats is mediated through activation of alpha 1-adrenoceptors. beta-Adrenoceptors in addition to alpha 1-adrenoceptors, became involved in mediating this effect in cells from animals treated with pertussis toxin. The accumulation of cyclic-AMP in response to epinephrine or isoproterenol was markedly increased in hepatocytes from pertussis-treated rats as compared to that observed in control cells. The accumulation of cyclic-AMP due to glucagon was also increased. It is suggested that pertussis toxin may release a constraint on adenylate cyclase activity by blocking the inhibitory coupling mechanism (Ni) or some other entity involved in the regulation of the activity of this enzyme.
Collapse
|
30
|
Corvera S, García-Sáinz JA. Hormonal stimulation of mitochondrial glutaminase. Effects of vasopressin, angiotensin II, adrenaline and glucagon. Biochem J 1983; 210:957-60. [PMID: 6870814 PMCID: PMC1154314 DOI: 10.1042/bj2100957] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Adrenaline (through alpha 1-adrenoceptors), vasopressin and angiotensin II stimulate mitochondrial glutaminase activity. This stimulation probably contributes to the ureogenic effect of these hormones. The activity of the enzyme is sensitive to Ca2+ depletion. A role of Ca2+ in hormonal modulation of glutaminase activity is suggested.
Collapse
|
31
|
|