scholarly journals Glucocorticoids regulate mRNA levels for subunits of the 19 S regulatory complex of the 26 S proteasome in fast-twitch skeletal muscles

2004 ◽  
Vol 378 (1) ◽  
pp. 239-246 ◽  
Author(s):  
Lydie COMBARET ◽  
Daniel TAILLANDIER ◽  
Dominique DARDEVET ◽  
Daniel BÉCHET ◽  
Cécile RALLIÈRE ◽  
...  
Keyword(s):  
Hormonal Regulation ◽  
Skeletal Muscles ◽  
Conclusive Evidence ◽  
Mrna Levels ◽  
Glucocorticoid Treatment ◽  
Regulatory Subunits ◽  
Regulatory Complex ◽  
Insulin Dependent ◽  
Fast Twitch

Circulating levels of glucocorticoids are increased in many traumatic and muscle-wasting conditions that include insulin-dependent diabetes, acidosis, infection, and starvation. On the basis of indirect findings, it appeared that these catabolic hormones are required to stimulate Ub (ubiquitin)–proteasome-dependent proteolysis in skeletal muscles in such conditions. The present studies were performed to provide conclusive evidence for an activation of Ub-proteasome-dependent proteolysis after glucocorticoid treatment. In atrophying fast-twitch muscles from rats treated with dexamethasone for 6 days, compared with pair-fed controls, we found (i) increased MG132-inhibitable proteasome-dependent proteolysis, (ii) an enhanced rate of substrate ubiquitination, (iii) increased chymotrypsin-like proteasomal activity of the proteasome, and (iv) a co-ordinate increase in the mRNA expression of several ATPase (S4, S6, S7 and S8) and non-ATPase (S1, S5a and S14) subunits of the 19 S regulatory complex, which regulates the peptidase and the proteolytic activities of the 26 S proteasome. These studies provide conclusive evidence that glucocorticoids activate Ub-proteasome-dependent proteolysis and the first in vivo evidence for a hormonal regulation of the expression of subunits of the 19 S complex. The results suggest that adaptations in gene expression of regulatory subunits of the 19 S complex by glucocorticoids are crucial in the regulation of the 26 S muscle proteasome.

scholarly journals Hormonal regulation of cholesterol 7alpha-hydroxylase specific activity, mRNA levels, and transcriptional activity in vivo in the rat

1997 ◽  
Vol 38 (12) ◽  
pp. 2483-2491 ◽  
Author(s):  
W M Pandak ◽  
D M Heuman ◽  
K Redford ◽  
R T Stravitz ◽  
J Y Chiang ◽  
...  
Keyword(s):  
Hormonal Regulation ◽  
Transcriptional Activity ◽  
Specific Activity ◽  
Mrna Levels

Glutamine synthetase induction by glucocorticoids is preserved in skeletal muscle of aged rats

1996 ◽  
Vol 271 (6) ◽  
pp. E1061-E1066 ◽  
Author(s):  
D. Meynial-Denis ◽  
M. Mignon ◽  
A. Miri ◽  
J. Imbert ◽  
E. Aurousseau ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Glutamine Synthetase ◽  
Skeletal Muscles ◽  
Female Rats ◽  
Mrna Levels ◽  
Aged Rats ◽  
Adult Rats ◽  
Adult Age ◽  
Slow Twitch ◽  
Fast Twitch

Glutamine synthetase (GS) is a glucocorticoid-inducible enzyme that has a key role for glutamine synthesis in muscle. We hypothesized that the glucocorticoid induction of GS could be altered in aged rats, because alterations in the responsiveness of some genes to glucocorticoids were reported in aging. We compared the glucocorticoid-induced GS in fast-twitch and slow-twitch skeletal muscles (tibialis anterior and soleus, respectively) and heart from adult (age 6-8 mo) and aged (age 22 mo) female rats. All animals received dexamethasone (Dex) in their drinking water (0.77 +/- 0.10 and 0.80 +/- 0.08 mg/day per adult and aged rat, respectively) for 5 days. Dex caused an increase in both GS activity and GS mRNA in fast-twitch and slow-twitch skeletal muscles from adult and aged rats. In contrast, Dex increased GS activity in heart of adult rats, without any concomitant change in GS mRNA levels. Furthermore, Dex did not affect GS activity in aged heart. Thus the responsiveness of GS to an excess of glucocorticoids is preserved in skeletal muscle but not in heart from aged animals.

Regulation of the epithelial Ca2+ channels in small intestine as studied by quantitative mRNA detection

2003 ◽  
Vol 285 (1) ◽  
pp. G78-G85 ◽  
Author(s):  
Monique van Abel ◽  
Joost G. J. Hoenderop ◽  
Annemiete W. C. M. van der Kemp ◽  
Johannes P. T. M. van Leeuwen ◽  
René J. M. Bindels
Keyword(s):  
Knockout Mice ◽  
Hormonal Regulation ◽  
Transport Proteins ◽  
Ovariectomized Rats ◽  
Mrna Levels ◽  
Hydroxyvitamin D ◽  
Dihydroxyvitamin D ◽  
Genes Encoding ◽  
Calbindin D

The epithelial Ca2+ channels TRPV5 and TRPV6 are localized to the brush border membrane of intestinal cells and constitute the postulated rate-limiting entry step of active Ca2+ absorption. The aim of the present study was to investigate the hormonal regulation of these channels. To this end, the effect of 17β-estradiol (17β-E2), 1,25-dihydroxyvitamin D3 [1,25(OH)2D3], and dietary Ca2+ on the expression of the duodenal Ca2+ transport proteins was investigated in vivo and analyzed using realtime quantitative PCR. Supplementation with 17β-E2 increased duodenal gene expression of TRPV5 and TRPV6 but also calbindin-D9K and plasma membrane Ca2+-ATPase (PMCA1b) in ovariectomized rats. 25-Hydroxyvitamin D3-1α-hydroxylase (1α-OHase) knockout mice are characterized by hyperparathyroidism, rickets, hypocalcemia, and undetectable levels of 1,25(OH)2D3 and were used to study the 1,25(OH)2D3-dependency of the stimulatory effects of 17β-E2. Treatment with 17β-E2 upregulated mRNA levels of duodenal TRPV6 in these 1α-OHase knockout mice, which was accompanied by increased serum Ca2+ concentrations from 1.69 ± 0.10 to 2.03 ± 0.12 mM ( P < 0.05). In addition, high dietary Ca2+ intake normalized serum Ca2+ in these mice and upregulated expression of genes encoding the duodenal Ca2+ transport proteins except for PMCA1b. Supplementation with 1,25(OH)2D3 resulted in increased expression of TRPV6, calbindin-D9K, and PMCA1b and normalization of serum Ca2+. Expression levels of duodenal TRPV5 mRNA are below detection limits in these 1α-OHase knockout mice, but supplementation with 1,25(OH)2D3 upregulated the expression to significant levels. In conclusion, TRPV5 and TRPV6 are regulated by 17β-E2 and 1,25(OH)2D3, whereas dietary Ca2+ is positively involved in the regulation of TRPV6 only.

scholarly journals Lack of Histamine Synthesis and Down-Regulation of H1 and H2 Receptor mRNA Levels by Dexamethasone in Cerebral Endothelial Cells

1999 ◽  
Vol 19 (3) ◽  
pp. 321-330 ◽  
Author(s):  
Kaj Karlstedt ◽  
Tina Sallmén ◽  
Krister S. Eriksson ◽  
Minnamaija Lintunen ◽  
Pierre-Olivier Couraud ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Cultured Cells ◽  
Histidine Decarboxylase ◽  
Mrna Levels ◽  
Glucocorticoid Treatment ◽  
Adult Rat ◽  
Receptor Mrna ◽  
Cerebral Endothelial Cells ◽  
Histamine Production

The purpose of this work was to determine whether cerebral endothelial cells have the capacity to synthesize histamine or to express mRNA of receptors that specifically respond to available free histamine. The histamine concentrations and the expression of L-histidine decarboxylase (HDC) and histamine H1 and H2 receptor mRNA, both in adult rat brain and in cultured immortalized RBE4 cerebral endothelial cells, were investigated. In this study endothelial cells were devoid of any kind of detectable histamine production, both in vivo and in the immortalized RBE4 cells in culture. Both the immunostainings for histamine and the in situ hybridizations for HDC were negative, as well as histamine determinations by HPLC, indicating that endothelial cells do not possess the capacity to produce histamine. Also, glucocorticoid (dexamethasone) treatment failed to induce histamine production in the cultured cells. Although the cerebral endothelial cells lack histamine production, a nonsaturable uptake in RBE4 cells is demonstrated. The internalized histamine is detected both in the cytoplasm and in the nucleus, which could indicate a role for histamine as an intracellular messenger. Histamine H1 and H2 receptor mRNA was expressed in RBE4 cells, and glucocorticoid treatment down-regulated the mRNA levels of both H1 and H2 receptors. This mechanism may be involved in glucocorticoid-mediated effects on cerebrovascular permeability and brain edema.

scholarly journals Hormonal regulation of aquaporin 3: opposing actions of prolactin and cortisol in tilapia gill

2016 ◽  
Vol 230 (3) ◽  
pp. 325-337 ◽  
Author(s):  
Jason P Breves ◽  
Mayu Inokuchi ◽  
Yoko Yamaguchi ◽  
Andre P Seale ◽  
Bethany L Hunt ◽  
...  
Keyword(s):  
Hormonal Regulation ◽  
Cell Membranes ◽  
Mrna Levels ◽  
Gill Epithelium ◽  
Aquaporin 3 ◽  
Gill Filaments ◽  
Branchial Epithelium ◽  
Hydromineral Balance

Aquaporins (Aqps) are expressed within key osmoregulatory tissues where they mediate the movement of water and selected solutes across cell membranes. We leveraged the functional plasticity of Mozambique tilapia (Oreochromis mossambicus) gill epithelium to examine how Aqp3, an aquaglyceroporin, is regulated in response to osmoregulatory demands. Particular attention was paid to the actions of critical osmoregulatory hormones, namely, prolactin (Prl), growth hormone and cortisol. Branchial aqp3 mRNA levels were modulated following changes in environmental salinity, with enhanced aqp3 mRNA expression upon transfer from seawater to freshwater (FW). Accordingly, extensive Aqp3 immunoreactivity was localized to cell membranes of branchial epithelium in FW-acclimated animals. Upon transferring hypophysectomized tilapia to FW, we identified that a pituitary factor(s) is required for Aqp3 expression in FW. Replacement with ovine Prl (oPrl) was sufficient to stimulate Aqp3 expression in hypophysectomized animals held in FW, an effect blocked by coinjection with cortisol. Both oPrl and native tilapia Prls (tPrl177 and tPrl188) stimulated aqp3 in incubated gill filaments in a concentration-related manner. Consistent with in vivo responses, coincubation with cortisol blocked oPrl-stimulated aqp3 expression in vitro. Our data indicate that Prl and cortisol act directly upon branchial epithelium to regulate Aqp3 in tilapia. Thus, within the context of the diverse actions of Prl on hydromineral balance in vertebrates, we define a new role for Prl as a regulator of Aqp expression.

scholarly journals PHYLOGENESIS, ETIOLOGY AND PATHOGENESIS OF INSULIN RESISTANCE. DIFFERENCES FROM TYPE II DIABETES MELLITUS

2012 ◽  
Vol 67 (4) ◽  
pp. 65-73
Author(s):  
V. N. Titov
Keyword(s):  
Diabetes Mellitus ◽  
Insulin Resistance ◽  
Fatty Acids ◽  
Hormonal Regulation ◽  
Type Ii Diabetes ◽  
Type Ii Diabetes Mellitus ◽  
Type Ii ◽  
Insulin Dependent ◽  
The One

We believe that etiological factor of insulin resistance is phylogenetically late formation of insulin and its specific functionality, i.e., providing energy substrates for the biological function of locomotion. According to biological subordination, insulin cannot change regulation formed at the early stages of phylogenesis in all cells, including those that become insulin-dependent at the late stages of phylogenesis. This involves a) β-oxidation of fatty acids in the mitochondria, b) synthesis of С 16:0 palmitic saturated fatty acid, c) glucose metabolism in pro- and eukaryotes, d) regulation of biochemical reactions in insulin-independent cells, e) humoral effects of mediators at the level of paracrine cell communities which are structural and functional units of all internal organs, and f) hormonal regulation at the entire organism level. Pathogenetic factors of insulin resistance are biochemical and functional disorders occurring in vivo upon activation of biological functions and reactions that formed phylogenetically earlier than insulin. During phylogenesis the insulin system has intrinsically built up over the regulatory mechanisms of mitochondria, early unicellular organisms and paracrine cell communities. Insulin functionally interacts with them all, but it cannot abolish the effects of any phylogenetically earlier humoral mediator. Insulin resistance is a pathophysiological disparity between humoral regulation of metabolism at the level of phylogenetically earlier paracrine cell communities and at the level of phylogenetically late total organism, on the one hand, and successive phylogenetic formation of passive cellular uptake of fatty acids as unesterified fatty acids and later triglycerides, on the other. If insulin resistance results from changes in the primary structure of transport proteins, in glucose storage and cellular insulin reception, it can be referred to as type II diabetes mellitus. 

Calsequestrin (CASQ1) rescues function and structure of calcium release units in skeletal muscles of CASQ1-null mice

2012 ◽  
Vol 302 (3) ◽  
pp. C575-C586 ◽  
Author(s):  
Mirta Tomasi ◽  
Marta Canato ◽  
Cecilia Paolini ◽  
Marco Dainese ◽  
Carlo Reggiani ◽  
...  
Keyword(s):  
Skeletal Muscles ◽  
Calcium Release ◽  
Fluorescent Protein ◽  
Adaptive Mechanisms ◽  
Flexor Digitorum Brevis ◽  
Green Fluorescent ◽  
Flexor Digitorum ◽  
Fast Twitch ◽  
Terminal Cisternae

Amplitude of Ca2+ transients, ultrastructure of Ca2+ release units, and molecular composition of sarcoplasmic reticulum (SR) are altered in fast-twitch skeletal muscles of calsequestrin-1 (CASQ1)-null mice. To determine whether such changes are directly caused by CASQ1 ablation or are instead the result of adaptive mechanisms, here we assessed ability of CASQ1 in rescuing the null phenotype. In vivo reintroduction of CASQ1 was carried out by cDNA electro transfer in flexor digitorum brevis muscle of the mouse. Exogenous CASQ1 was found to be correctly targeted to the junctional SR (jSR), as judged by immunofluorescence and confocal microscopy; terminal cisternae (TC) lumen was filled with electron dense material and its width was significantly increased, as judged by electron microscopy; peak amplitude of Ca2+ transients was significantly increased compared with null muscle fibers transfected only with green fluorescent protein (control); and finally, transfected fibers were able to sustain cytosolic Ca2+ concentration during prolonged tetanic stimulation. Only the expression of TC proteins, such as calsequestrin 2, sarcalumenin, and triadin, was not rescued as judged by Western blot. Thus our results support the view that CASQ1 plays a key role in both Ca2+ homeostasis and TC structure.

scholarly journals Phosphorylation in vivo of the P light chain of myosin in rabbit fast and slow skeletal muscles

1984 ◽  
Vol 218 (3) ◽  
pp. 841-847 ◽  
Author(s):  
S A Westwood ◽  
O Hudlicka ◽  
S V Perry
Keyword(s):  
Light Chain ◽  
Skeletal Muscles ◽  
Time Course ◽  
Electrophoretic Mobilities ◽  
Slow Twitch Muscle ◽  
Post Tetanic Potentiation ◽  
Slow Twitch ◽  
Fast Twitch ◽  
Frequency Of Stimulation

The P light chain of myosin is partially phosphorylated in resting slow and fast twitch skeletal muscles of the rabbit in vivo. The extent of P light-chain phosphorylation increases in both muscles on stimulation. Rabbit slow-twitch muscles contain two forms of the P light chain that migrate with the same electrophoretic mobilities as the two forms of P light chain in rabbit ventricular muscle. The rate of phosphorylation of the P light chain in slow-twitch muscle is slower than its rate of phosphorylation in fast-twitch muscles during tetanus. The rate of P light-chain dephosphorylation is slow after tetanic contraction of fast-twitch muscles in vivo. The time course of dephosphorylation does not correlate with the decline of post-tetanic potentiation of peak twitch tension in rabbit fast-twitch muscles. The frequency of stimulation is an important factor in determining the extent of P light-chain phosphorylation in fast- and slow-twitch muscles.

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