Phenylalanine hydroxylation in isolated rat kidney tubules

Askin, David; Green, Anne K.; Dickson, Alan J.; Fisher, Michael J.

doi:10.1016/0020-711x(90)90085-h

Cited by 11 publications

(11 citation statements)

References 28 publications

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“…The basal, lactate-supported glucose production was similar to that observed previously by ourselves (Askin et al 1990) and other workers (Cha et al 1995), thereby confirming the metabolic viability of the tubule preparations. Exogenous ATP provoked an approximately 50% stimulation of the lactate-supported gluconeogenic rate, essentially similar to that previously reported (Edgecombe et al 1997).…”

Section: Resultssupporting

confidence: 87%

“…Proximal tubules were prepared essentially as described previously (Askin et al 1990). Briefly, immediately after rats had been killed by cervical dislocation, each kidney was perfused in situ with 5 ml of ice-cold Krebs-Henseleit buffer containing (mM): 120 NaCl, 5 KCl, 1.2 KH 2 PO 4 , 1.2 MgSO 4 (Krebs and Henseleit 1932) supplemented with collagenase (1 mg/ml).…”

Section: Methodsmentioning

confidence: 99%

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Uridine nucleotide-induced stimulation of gluconeogenesis in isolated rat proximal tubules

Fisher

2002

Naunyn-Schmiedeberg's Archives of Pharmacology

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Uridine nucleotides, released into the extracellular environment, influence a variety of metabolic and other cellular activities in a wide range of target tissues. Here we have studied the effects of uridine nucleotides on gluconeogenesis in isolated rat proximal tubules. Gluconeogenesis, from a range of precursors, was stimulated following exposure of isolated proximal tubules to either UTP or UTPgammaS, but not when exposed to other uridine-containing nucleotides. UTP- and UTPgammaS-induced gluconeogenesis was diminished in the presence of purinoceptor antagonists (e.g. suramin, PPADS) indicative of a role for P2Y(2)-like purinoceptors in these effects. Likewise, agents that interfere with either phospholipase C activation or intracellular Ca2+ mobilization decreased UTP- and UTPgammaS-induced stimulation of gluconeogenesis consistent with a role for these secondary messenger systems in the mechanism of action of extracellular UTP and UTPgammaS on proximal tubule metabolism.

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Section: Resultssupporting

confidence: 87%

Section: Methodsmentioning

confidence: 99%

Uridine nucleotide-induced stimulation of gluconeogenesis in isolated rat proximal tubules

Fisher

2002

Naunyn-Schmiedeberg's Archives of Pharmacology

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“…To the best of our knowledge this is the first report of cyclic AMPstimulated phosphorylation of kidney phenylalanine hydroxylase. Other workers have been unable to demonstrate cyclic AMP-stimulated phosphorylation of enzyme purified from kidney (Rao & Kaufman, 1986 (Askin et al, 1989) has also indicated that the relationship between cyclic AMP-induced alterations in phosphorylation state and phenylalanine hydroxylation in isolated kidney tubules is less marked than in the hepatic system. General conclusions The present paper describes the use of the monoclonal antibody PH 7 for the rapid non-radioactive analysis of alterations in the phosphorylation state of phenylalanine hydroxylase in crude cell extracts from a variety of tissues.…”

Section: Preparation and Incubation Of Liver Cells And Kidney Tubulesmentioning

confidence: 99%

Experimental determination of the phosphorylation state of phenylalanine hydroxylase

Green

Cotton

Jennings

et al. 1990

Biochemical Journal

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A monoclonal antibody (PH 7), which recognizes the phosphorylated form of phenylalanine hydroxylase from human liver, has been used for the analysis of the enzyme in crude cell extracts from rat. In immunoblot analyses of rat liver cell extracts, the extent of binding of PH 7 closely correlates with the phosphorylation state of phenylalanine hydroxylase, as judged by [32P]Pi incorporation. These observations have made possible the rapid non-radioactive quantification of hormonal effects on phenylalanine hydroxylase phosphorylation state. In particular, the glucagon-dependent phosphorylation of phenylalanine hydroxylase in liver cells was investigated. Epidermal growth factor was shown to modulate this process. In addition, this technique was used to demonstrate, for the first time, that dibutyryl cyclic AMP, unlike the Ca2" ionophore A23187, stimulates the phosphorylation of phenylalanine hydroxylase in isolated kidney tubules from rat.

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“…Rat kidney tubules were prepared and incubated as described in [7]. Quantification of the phosphate content of phenylalanine hydroxylase was assessed by two methods.…”

mentioning

confidence: 99%