Effect of starvation and refeeding on polyamine concentrations and ornithine decarboxylase antizyme in mammary gland of lactating rats

Brosnan, Margaret E.; Farrell, Rosemary; Wilansky, H; Williamson, D.

doi:10.1042/bj2120149

Cited by 23 publications

(7 citation statements)

References 24 publications

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“…However, these changes do not correlate closely with the onset of lactose synthesis (Kuhn & Lowenstein, 1967;Kuhn, 1969;McKenzie et al, 1971). Moreover, the large changes in lactose synthesis that occur when lactating rats are starved and then re-fed (Carrick & Kuhn, 1978) are not accompanied by changes in tissue spermidine and spermine even though similarly large changes are seen in the activity of ornithine decarboxylase (Brosnan et al, 1982(Brosnan et al, , 1983. Finally, when the binding of polyamines to ribosomes, tRNA and other polyanions is considered, it is unlikely that their free concentration is more than a fraction of the total.…”

Section: Polyamines As Possible Activatorsmentioning

confidence: 98%

Cationic activation of galactosyltransferase from rat mammary Golgi membranes by polyamines and by basic peptides and proteins

Navaratnam¹,

Virk²,

Ward³

et al. 1986

Biochemical Journal

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Galactosyltransferase (EC 2.4.1.22) requires bivalent metal ions for its activity. However, preparations of this enzyme solubilized from Golgi membranes of lactating rat mammary gland were shown to be activated not only by Mn2+, Ca2+ and Mg2+, but also by spermine, spermidine, lysyl-lysine, ethylenediamine and other diaminoalkanes, and by a range of basic proteins and peptides, including clupeine, histone, polylysine, ribonuclease, pancreatic trypsin inhibitor, cytochrome c, melittin, avidin and myelin basic protein. Both N-acetyl-lactosamine synthetase and lactose synthetase activities were enhanced. A basic protein fraction was isolated from bovine milk and shown to activate galactosyltransferase at low concentrations. The polyanions ATP, casein, chondroitin sulphate and heparin reversed the activation of galactosyltransferase by several of the above substances. Galactosyltransferase, assayed as a lactose synthetase, showed a 10-fold greater affinity for glucose when Mn2+ ions were replaced by clupeine or by ribonuclease as cationic activator. Evidence was obtained for the presence of an endogenous cationic activator in solubilized Golgi membrane preparations which evoked a similar low apparent Km,glucose. The findings are discussed in the light of cationic activations of glycosyltransferases generally, of the porous nature of the Golgi membrane, and of the unlikelihood of bivalent metal ions being the physiological activators of galactosyltransferase. It is suggested that the natural cationic activator of lactose synthetase may be a secretory protein acting in a manner analogous to the enzyme's activation by alpha-lactalbumin. A scheme is proposed for the two-stage synthesis of lactose and phosphorylation of casein within the cell, to accommodate the apparent incompatibility of these two processes.

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Section: Polyamines As Possible Activatorsmentioning

confidence: 98%

Cationic activation of galactosyltransferase from rat mammary Golgi membranes by polyamines and by basic peptides and proteins

Navaratnam¹,

Virk²,

Ward³

et al. 1986

Biochemical Journal

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“…Antizyme has been detected in mouse brain (Hietala, 1983) and rat mammary glands (Brosnan et al, 1983) without any treatment with exogenous polyamines, suggesting possible roles of antizyme under physiological conditions. However, the evidence for identification as antizyme seems to be insufficient in those studies as judged by our criteria.…”

mentioning

confidence: 98%

Antizyme to ornithine decarboxylase is present in the liver of starved rats

Fujita¹,

Matsufuji²,

Murakami³

et al. 1984

Biochemical Journal

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Antizyme to ornithine decarboxylase (ODC) and ODC-antizyme complex were both present in liver cytosols of starved rats. The antizyme was identified by its molecular weight, kinetic properties, formation of a complex with ODC, and reversal of its inhibition by antizyme inhibitor. The average amount of antizyme in liver cytosols of starved rats was 0.1 unit/mg of protein, roughly corresponding to basal hepatic ODC activity in rats fed ad libitum. The presence of ODC-antizyme complex was detected by using antizyme inhibitor. These results indicate that antizyme participates in the regulation of ODC activity in vivo under physiological conditions.

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“…In normal rat liver or H35 cells, small amounts of antizyme were found in the nuclei or in the post-ribosomal nucleoprotein particles [9]. Recently, bound forms of antizyme were reported in rat mammary glands [2] and in the liver of starved rats [7].…”

Section: Discussionmentioning

confidence: 99%

Purification of a non-histone protein with properties of antizyme to ornithine decarboxylase from germinated barley seeds

Panagiotidis

Kyriakidis

1985

Plant Growth Regul

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The purification of a chromatin-bound antizyme to ornithine decarboxylase from germinated barley seeds is described. This antizyme was extracted from chromatin by 2M NaC1 and purified to homogeneity. Its molecular weight was found to be 9000 with an isoelectric point of 4.1. It reacts with both cytosolic and chromatinbound ornithine decarboxylase from germinated barley seeds and E. coli, but it does not inhibit ornithine decarboxylase of Tetrahymena pyriformis or rat liver.

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Effect of starvation and refeeding on polyamine concentrations and ornithine decarboxylase antizyme in mammary gland of lactating rats

Cited by 23 publications

References 24 publications

Cationic activation of galactosyltransferase from rat mammary Golgi membranes by polyamines and by basic peptides and proteins

Cationic activation of galactosyltransferase from rat mammary Golgi membranes by polyamines and by basic peptides and proteins

Antizyme to ornithine decarboxylase is present in the liver of starved rats

Purification of a non-histone protein with properties of antizyme to ornithine decarboxylase from germinated barley seeds

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