Clenbuterol prevents or inhibits loss of specific mRNAs in atrophying rat skeletal muscle

It is known that denervation or hindlimb suspension both decrease the content of rRNA, alpha-actin mRNA, and cytochrome c mRNA in adult rat skeletal muscle. In the present study, the provision of clenbuterol (an anabolic agent) to adult female rats during a 7-day period of denervation of the soleus and gastrocnemius muscles prevented entirely the loss of rRNA, alpha-actin mRNA, and cytochrome c mRNA that normally occurs in denervated muscle. Although clenbuterol inhibited most of the loss of alpha-actin mRNA that occurred in the soleus and gastrocnemius muscles after 7 days of hindlimb suspension, clenbuterol administration had less effect on preventing the loss of rRNA and cytochrome c mRNA in hindlimb suspended skeletal muscle. Clenbuterol had no effect on protein content in atrophied muscle resulting from denervation or suspension. These data suggest that clenbuterol can maintain the expression of certain RNAs in atrophying adult rat skeletal muscle.

Download Full-text

Daily running for 2 wk and mRNAs for cytochrome c and alpha-actin in rat skeletal muscle

AJP Cell Physiology ◽

10.1152/ajpcell.1989.257.5.c936 ◽

1989 ◽

Vol 257 (5) ◽

pp. C936-C939 ◽

Cited By ~ 11

Author(s):

P. R. Morrison ◽

R. B. Biggs ◽

F. W. Booth

Keyword(s):

Skeletal Muscle ◽

Cytochrome C ◽

Training Program ◽

Citrate Synthase ◽

Mitochondrial Protein ◽

Female Rats ◽

Hindlimb Muscles ◽

Actin Mrna ◽

Alpha Actin ◽

Fast Twitch

The purpose of the study was to determine whether daily running durations that were 7-14% of the durations employed in the chronic stimulation protocols (consisting of 24 h of daily indirect electrical stimulation of skeletal muscles) still resulted in increases in a mitochondrial protein mRNA. Adult female rats were run 100 min/day on motor-driven treadmills for 2 wk. Documentation that rats underwent the stated training program was obtained by a 30-41% increase in citrate synthase activity in hindlimb muscles after 2 wk of the training. Cytochrome c mRNA was increased 17-56% in hindlimb muscles after the 2-wk training program. Thus shorter durations of exercise (100 min/day rather than 24 h/day) can increase cytochrome c mRNA. alpha-Actin mRNA increased 61-62% in fast-twitch muscles in the hindlimbs of the same rats that underwent the 2 wk of run training but did not increase in the predominantly slow-twitch soleus muscle. The increase in alpha-actin mRNA was unexpected, since it is well known that this type of physical exercise does not increase the size of fast-twitch skeletal muscle.

Download Full-text

alpha-Actin proteins and gene transcripts are colocalized in embryonic mouse muscle

Development ◽

10.1242/dev.111.2.451 ◽

1991 ◽

Vol 111 (2) ◽

pp. 451-454 ◽

Cited By ~ 1

Author(s):

G.E. Lyons ◽

M.E. Buckingham ◽

H.G. Mannherz

Keyword(s):

Skeletal Muscle ◽

Striated Muscle ◽

Mouse Muscle ◽

Embryonic Mouse ◽

Gene Transcripts ◽

Specific Mrnas ◽

Actin Mrna ◽

Embryo Sections ◽

Alpha Actin

The alpha-actins are among the earliest muscle-specific mRNAs to appear in developing cardiac and skeletal muscle. To determine if there is coexpression of the alpha-actin proteins at early stages of myogenesis, we have used an alpha-actin-specific polyclonal antibody and in situ hybridization with specific cRNA probes to cardiac and skeletal alpha-actin transcripts on serial slides of mouse embryo sections. As soon as we can detect alpha-actin mRNAs in embryonic striated muscle, we also detect the protein suggesting that alpha-actin transcripts are translated very rapidly after transcription during myogenesis. In skeletal muscle, this colocalization of alpha-actin mRNA and protein was observed both in the myotomes of somites and in developing muscles in the limbs. In cardiac muscle, alpha-actin transcripts and proteins are abundantly expressed as soon as a cardiac tube forms.

Download Full-text

Regulation of glucose transporter GLUT-4 and hexokinase II gene transcription by insulin and epinephrine

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.1997.273.4.e682 ◽

1997 ◽

Vol 273 (4) ◽

pp. E682-E687 ◽

Cited By ~ 11

Author(s):

Jared P. Jones ◽

G. Lynis Dohm

Keyword(s):

Skeletal Muscle ◽

Gene Transcription ◽

Glucose Transporter ◽

Male Rats ◽

Rat Skeletal Muscle ◽

Hexokinase Ii ◽

Epinephrine Infusion ◽

Glut 4 ◽

Gastrocnemius Muscles

Transport of glucose across the plasma membrane by GLUT-4 and subsequent phosphorylation of glucose by hexokinase II (HKII) constitute the first two steps of glucose utilization in skeletal muscle. This study was undertaken to determine whether epinephrine and/or insulin regulates in vivo GLUT-4 and HKII gene transcription in rat skeletal muscle. In the first experiment, adrenodemedullated male rats were fasted 24 h and killed in the control condition or after being infused for 1.5 h with epinephrine (30 μg/ml at 1.68 ml/h). In the second experiment, male rats were fasted 24 h and killed after being infused for 2.5 h at 1.68 ml/h with saline or glucose (625 mg/ml) or insulin (39.9 μg/ml) plus glucose (625 mg/ml). Nuclei were isolated from pooled quadriceps, tibialis anterior, and gastrocnemius muscles. Transcriptional run-on analysis indicated that epinephrine infusion decreased GLUT-4 and increased HKII transcription compared with fasted controls. Both glucose and insulin plus glucose infusion induced increases in GLUT-4 and HKII transcription of twofold and three- to fourfold, respectively, compared with saline-infused rats. In conclusion, epinephrine and insulin may regulate GLUT-4 and HKII genes at the level of transcription in rat skeletal muscle.

Download Full-text

Alpha-actin and cytochrome c mRNAs in atrophied adult rat skeletal muscle

AJP Cell Physiology ◽

10.1152/ajpcell.1988.254.5.c651 ◽

1988 ◽

Vol 254 (5) ◽

pp. C651-C656 ◽

Cited By ~ 36

Author(s):

P. Babij ◽

F. W. Booth

Keyword(s):

Skeletal Muscle ◽

Cytochrome C ◽

Muscle Atrophy ◽

Weight Bearing ◽

Skeletal Muscle Atrophy ◽

Rna Content ◽

Mrna Content ◽

Fast Twitch Muscle ◽

Alpha Actin ◽

Fast Twitch

Specific complementary DNA (cDNA) hybridization probes were used to estimate the levels of alpha-actin and cytochrome c mRNAs and also 18S rRNA in three models of skeletal muscle atrophy. After 7 days of hindlimb suspension, or immobilization, or denervation, protein content decreased 26-32% in all muscles studied except suspended fast-twitch muscle, which lost only half as much protein. alpha-Actin mRNA content decreased 51-66% and cytochrome c mRNA content decreased 42-61% in slow- and fast-twitch muscles in all three models of atrophy. However, total RNA content did not show similar directional changes; RNA content decreased 27-44% in suspended and immobilized muscle but was unchanged in denervated fast-twitch muscle. The results were interpreted to suggest that loss of weight-bearing function of skeletal muscle is a major factor affecting the levels of alpha-actin and cytochrome c mRNAs during muscle atrophy.

Download Full-text

Localization of Epitopes for Monoclonal Antibodies Directed against the Adult Rat Skeletal Muscle Sodium Channel (rSkM1) Using Polymerase Chain Reaction, Fusion Proteins, and Western Blotting

Analytical Biochemistry ◽

10.1006/abio.1995.1210 ◽

1995 ◽

Vol 226 (1) ◽

pp. 188-191 ◽

Cited By ~ 2

Author(s):

W.J. Sun ◽

S.A. Cohen ◽

R.L. Barchi

Keyword(s):

Skeletal Muscle ◽

Polymerase Chain Reaction ◽

Monoclonal Antibodies ◽

Sodium Channel ◽

Western Blotting ◽

Fusion Proteins ◽

Rat Skeletal Muscle ◽

Chain Reaction ◽

Adult Rat ◽

Polymerase Chain

Download Full-text

Stable incorporation of a bacterial gene into adult rat skeletal muscle in vivo

AJP Cell Physiology ◽

10.1152/ajpcell.1990.258.3.c578 ◽

1990 ◽

Vol 258 (3) ◽

pp. C578-C581 ◽

Cited By ~ 33

Author(s):

D. B. Thomason ◽

F. W. Booth

Keyword(s):

Skeletal Muscle ◽

Leukemia Virus ◽

Rat Skeletal Muscle ◽

Bacterial Gene ◽

Muscle Gene Expression ◽

Adult Rat ◽

Foreign Genes ◽

Muscle Gene ◽

Beta Galactosidase

We have developed a novel technique to incorporate and stably express foreign genes in adult rat skeletal muscle in vivo. Endogeneous satellite cells in skeletal muscle regenerating from bupivacaine damage were infected with an injected retrovirus containing the Escherichia coli beta-galactosidase gene under the promoter control of the Moloney murine leukemia virus long-terminal repeat. Constitutive and stable expression of beta-galactosidase activity was observed in muscle fibers after 6 days and 1 mo of muscle regeneration. Two patterns of expression were observed, diffuse expression within fibers and focal expression associated with the sarcolemma. This technique will allow future experiments with muscle-specific genes and promoters to study the physiological regulation of skeletal muscle gene expression in the intact adult mammal. Furthermore, the technique of stimulating stem cell proliferation to allow retroviral-mediated gene transfer may be generally applicable to other tissues.

Download Full-text