Localization of Na,K-ATPase activity in developing rat distal colon: role of corticosteroids

Zemanová, Z.; Pácha, Jiřı́

doi:10.1016/s0047-6374(97)00170-x

Cited by 12 publications

(6 citation statements)

References 25 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Data supporting this conclusion have recently been published by Nanthakumar and Henning (32) and Beckett et al (33) for the glucocorticoid induction of sucrase. In contrast to sucrase and alkaline phosphatase, CBX stimulated Na,K-ATPase activity in the colon but not in the small intestine, even though glucocorticoids have been shown to stimulate this enzyme activity in both the small and large intestines (13)(14)(15). Two possibilities may account for this discrepancy.…”

Section: Discussionmentioning

confidence: 94%

“…With regard to cell differentiation, weaning is characterized by phenotypic changes in enterocytes that include developmental changes in the activity of various enzymes influenced by the hormonal milieu, including glucocorticoids (1,5). For example, glucocorticoids have been shown to affect the developmental patterns of sucrase (10,11), alkaline phosphatase (12), and Na,K-ATPase (13)(14)(15).…”

mentioning

confidence: 99%

See 1 more Smart Citation

Carbenoxolone Accelerates Maturation of Rat Intestine

2003

View full text Add to dashboard Cite

The rat undergoes profound maturational changes in the intestinal structure and function during the third week of its life. To investigate the role of peripheral glucocorticoid metabolism in this process, we studied the postnatal maturation of intestinal structure and function. The peripheral metabolism of glucocorticoids depends on enzyme 11␤-hydroxysteroid dehydrogenase (11␤HSD), which is responsible for the interconversion of corticosterone to 11-dehydrocorticosterone and thus for the modulation of glucocorticoid access to corticosteroid receptors. The pups were treated with carbenoxolone (CBX), an inhibitor of 11␤HSD, for 10 d during the suckling (days 8 -18) or weaning period (days 14 -24 or days 20 -30), and we determined the parameters of intestinal growth and activities of sucrase, alkaline phosphatase, and Na,K-ATPase. The CBX treatment increased plasma concentrations of corticosterone as a result of a significant reduction of peripheral degradation of corticosterone catalyzed by 11␤HSD. This also stimulated intestinal growth without changing somatic growth. The mucosal cell mass was significantly higher in CBX-treated suckling rats, whereas the effect of this treatment was less obvious in weanling animals. CBX increased the crypt depth and villus height in 18-and 24-d-old pups but not in 30-d-old animals. The small intestinal activities of sucrase, alkaline phosphatase, and Na,K-ATPase were not influenced by CBX. In contrast, colonic Na,K-ATPase was stimulated by CBX. We conclude that the administration of CBX results in acceleration of intestinal growth and structural maturation without any influence on the developmental pattern of brush-border hydrolases The concentration of glucocorticoids in the plasma plays an important physiologic role in the promotion of normal ontogeny of the human embryo in utero and of rodents during weaning. The rise of plasma glucocorticoids is associated with an accelerated maturation of various tissues (1). The local action of glucocorticoids in target tissues can be modified by changes in peripheral glucocorticoid metabolism. This metabolism depends on the enzyme 11␤-hydroxysteroid dehydrogenase (11␤HSD), which has been recognized to play a key role in regulating the access of glucocorticoids to corticosteroid receptors. Two isoforms of 11␤HSD with different properties and tissue distribution have been described. Type 2 11␤HSD is a high-affinity NAD-dependent isozyme that catalyzes the conversion of cortisol and corticosterone to cortisone and 11-dehydrocorticosterone, respectively, and thus decreases the local concentration of active glucocorticoids and prevents their binding to mineralocorticoid receptors. In contrast, type 1 11␤HSD is a NADP(H)-dependent isoform that exhibits bidirectional activity in vitro but seems to favor 11-reductase activity in intact cells. Whereas type 2 has been predominantly found in the kidney, colonic epithelium, and placenta, type 1 is the predominant type in the liver, fibroblasts, and cells of lamina propria (2).It has recently been sho...

show abstract

Section: Discussionmentioning

confidence: 94%

mentioning

confidence: 99%

Carbenoxolone Accelerates Maturation of Rat Intestine

2003

View full text Add to dashboard Cite

show abstract

“…Na ϩ is extruded across the basolateral membrane by Na ϩ -K ϩ -ATPase (Na ϩ pump) that increases during the suckling and weaning period (295,353,449,450). The developmental increase in Na ϩ -K ϩ -ATPase activity fol-lows the mRNA expression for ␣and ␤-subunits of this protein, and their expression reaches adult levels at the end of weaning (125, 450).…”

Section: Postnatal Developmentmentioning

confidence: 99%

“…Aldosterone increases the entrance of Na ϩ across the apical membrane by induction of amiloride-sensitive Na ϩ channels (292,425) and the extrusion of Na ϩ across the basolateral membrane by stimulating the sodium pump, i.e., Na ϩ -K ϩ -ATPase (109,449). At present it is not clear whether the cellular effect of aldosterone is primarily a direct hormonal effect on the pump activity or whether the increased basolateral Na ϩ extrusion is the substrate effect due to higher apical Na ϩ permeability and higher intracellular Na ϩ .…”

Section: B Endocrine Signalsmentioning

confidence: 99%

Development of Intestinal Transport Function in Mammals

Pácha

2000

Physiological Reviews

340

281

View full text Add to dashboard Cite

Considerable progress has been made over the last decade in the understanding of mechanisms responsible for the ontogenetic changes of mammalian intestine. This review presents the current knowledge about the development of intestinal transport function in the context of intestinal mucosa ontogeny. The review predominantly focuses on signals that trigger and/or modulate the developmental changes of intestinal transport. After an overview of the proliferation and differentiation of intestinal mucosa, data about the bidirectional traffic (absorption and secretion) across the developing intestinal epithelium are presented. The largest part of the review is devoted to the description of developmental patterns concerning the absorption of nutrients, ions, water, vitamins, trace elements, and milk-borne biologically active substances. Furthermore, the review examines the development of intestinal secretion that has a variety of functions including maintenance of the fluidity of the intestinal content, lubrication of mucosal surface, and mucosal protection. The age-dependent shifts of absorption and secretion are the subject of integrated regulatory mechanisms, and hence, the input of hormonal, nervous, immune, and dietary signals is reviewed. Finally, the utilization of energy for transport processes in the developing intestine is highlighted, and the interactions between various sources of energy are discussed. The review ends with suggestions concerning possible directions of future research.

show abstract

“…Genomic effects produced by binding to nuclear receptors would take longer than 15 min. Membrane steroid receptors have been identified on several cell types, including synaptic membranes (32) and have been shown to be developmentally regulated (32,33). Their relative binding affinities for the different adrenal steroids is not known, although radioligand binding studies indicate that the high‐affinity recognition sites for [ 3 H]corticosterone in brain membranes have a low affinity for aldosterone (34).…”

Section: Discussionmentioning

confidence: 99%

The Acute Anticonvulsant Effects of Deoxycorticosterone in Developing Rats: Role of Metabolites and Mineralocorticoid‐receptor Responses

Edwards¹,

Vimal²,

Burnham³

2005

Epilepsia

View full text Add to dashboard Cite

Summary:Purpose: The mechanisms that mediate the acute anticonvulsant effects of deoxycorticosterone (DOC) were investigated in young rats.Methods: Fifteen-day-old rats were pretreated with a variety of compounds, including (a) agonists of the receptors that bind DOC (mineralocorticoid receptors); (b) the DOC 5α− and 5α-3α-reduced metabolites, plus agonists that bind the receptors of the 5α−reduced metabolite of DOC (progesterone receptors); and (c) DOC itself in the presence and absence of metabolism and receptor blockers. Fifteen minutes later, pentylenetetrazol (PTZ) was administered, and maximal pentylenetetrazol (MMT) seizure responses were scored.Results: Agonists of mineralocorticoid receptors increased the latency to forelimb flexion in PTZ seizures and sometimes suppressed the seizures completely. At low, nonconvulsant doses, spironolactone (a mineralocorticoid-receptor antagonist) blocked the anticonvulsant effects of a nonsedating, but not a sedating, dose of DOC. These data suggest the possible direct involvement of mineralocorticoid receptors in the anticonvulsant effects of DOC. At low, nonconvulsant doses, finasteride (which blocks the metabolism of DOC) partially blocked the protective effects of DOC, suggesting the contribution of metabolites to the anticonvulsant actions of DOC. Dihydrodeoxycorticosterone (DHDOC)-the first metabolite of DOC, an agonist at progesterone receptors, and an allosteric modulator of the γ -aminobutyric acid (GABA) A receptor-and tetrahydrodeoxycorticosterone, a secondary metabolite of DOC and an allosteric modulator of the GABA A receptor, both blocked MMT seizures.Conclusions: These findings suggest that both DOC and its metabolites may contribute to the anticonvulsant effects seen in young rats, perhaps acting via interactions with several different receptors.

show abstract

Localization of Na,K-ATPase activity in developing rat distal colon: role of corticosteroids

Cited by 12 publications

References 25 publications

Carbenoxolone Accelerates Maturation of Rat Intestine

Carbenoxolone Accelerates Maturation of Rat Intestine

Development of Intestinal Transport Function in Mammals

The Acute Anticonvulsant Effects of Deoxycorticosterone in Developing Rats: Role of Metabolites and Mineralocorticoid‐receptor Responses

Contact Info

Product

Resources

About