EFFECTS OF INSULIN ON THE INTACT LEVATOR ANI MUSCLE OF THE RAT

1967 ◽  
Vol 56 (2) ◽  
pp. 295-307 ◽  
Author(s):  
A. Arvill ◽  
K. Ahrén
Keyword(s):  
Amino Acids ◽  
Actinomycin D ◽  
Muscle Protein ◽  
Levator Ani ◽  
Levator Ani Muscle ◽  
Intracellular Accumulation ◽  
Insulin Stimulation ◽  
Significant Stimulation ◽  
Stimulation Of

ABSTRACT The effects of insulin on the rate of intracellular accumulation and incorporation into the protein of some normal amino acids (glycine-3H, leucine-14C and valine-14C) in the intact levator ani muscle of the rat were studied in vitro. The effect of puromycin on the accumulation of these amino acids as well as on the accumulation of the model amino acid α-aminoisobutyric acid-14C (AIB-14C) was examined. In addition the effect of insulin on the incorporation of adenine-14C into the muscle RNA as well as on the effect of actinomycin D added to the incubation medium were also investigated. The insulin stimulated AIB-14C transport is described by the formulation of Michaelis-Menten and approximate values of Km and Vmax are calculated for this transport in the levator ani muscle. Insulin was found to stimulate the intracellular accumulation of glycine-3H and AIB-14C, while a significant decrease was found in the accumulation of leucine-14C and valine-14C. Insulin also stimulated the incorporation of glycine-3H and leucine-14C into the muscle protein. When puromycin was added to the medium, no radioactivity was found in the protein fraction and insulin then stimulated the intracellular accumulation of glycine-3H, leucine-14C and AIB-14C. A slight but significant stimulation with insulin was found on the incorporation of adenine-14C into the RNA-fraction of the levator ani muscle. The addition of actinomycin D was found to inhibit this effect of insulin, but did not change the insulin stimulation of the AIB-14C accumulation. The results are discussed in relation to our present knowledge of the different in vitro effects of insulin.

EFFECTS OF TESTOSTERONE ON THE METABOLISM OF THE ISOLATED LEVATOR ANI MUSCLE OF THE RAT

1967 ◽  
Vol 56 (3_Suppl) ◽  
pp. S1-S14 ◽  
Author(s):  
A. Arvill
Keyword(s):  
Incubation Period ◽  
Protein Fraction ◽  
Muscle Protein ◽  
Levator Ani ◽  
Male Rats ◽  
Levator Ani Muscle ◽  
Intracellular Accumulation ◽  
Immature Male

ABSTRACT The effects of restosterone were studied on the rate of intracellular accumulation of D-xylose-14C, AIB-14C, glycine-3H, valine-14C and leucine-14C in the isolated levator ani muscle of immature male rats. The effects of testosterone were also investigated on the incorporation of glycine-3H and leucine-14C into the muscle protein as well as on the incorporation of adenine-14C in muscle RNA. The testosterone stimulated AIB transport is described by the formulation of Michaelis-Menten and approximate values of Km and Vmax are calculated for this transport in the levator ani muscle. Testosterone stimulated the intracellular accumulation of D-xylose-14C, AIB-14C and glycine-3H, but only when injected to the rats at least six hours before the in vitro experiment. No effect could be observed when testosterone was added to the incubation media. Testosterone also stimulated the incorporation of glycine-3H and leucine-14C into the muscle protein. When puromycin was added to the medium no radioactivity was found in the protein fraction. Stimulating effects during the incubation period, of previously injected testosterone, were nevertheless observed on the intracellular accumulation of AIB-14C, glycine-3H and valine-14C. Testosterone also stimulated the incorporation of adenine-14C into the muscle RNA. No effects on these parameters were ever observed in the diaphragm muscles of the same rats.

EFFECTS OF INSULIN ON THE INTACT LEVATOR ANI MUSCLE OF THE RAT

1967 ◽  
Vol 56 (2) ◽  
pp. 279-294 ◽  
Author(s):  
A. Arvill ◽  
K. Ahrén
Keyword(s):  
Incubation Medium ◽  
Levator Ani ◽  
Levator Ani Muscle ◽  
Intracellular Accumulation ◽  
Dose Response Relationship ◽  
Rapid Reduction ◽  
Intracellular Compartments ◽  
Insulin Activity ◽  
Dose Levels

ABSTRACT Effects of insulin in vitro on the rate of intracellular accumulation of α-aminoisobutyric acid (AIB) and D-xylose were studied in the intact levator ani muscle prepared as described by Arvill & Ahrén (1966 a). In some of the experiments the effects of insulin were also studied in the intact diaphragm preparation of Kipnis & Cori (1957). Insulin increased the rate of uptake of AIB and D-xylose in both preparations. A linear dose-response relationship was found within certain dose levels of insulin for the AIB transport in the levator ani preparation. The sensitivity to insulin of the AIB transport was found to be greater in summer than in winter. Addition of glucose to the incubation medium decreased the rate of penetration of D-xylose into the levator ani muscle but it did not influence the rate of AIB uptake or the effect of insulin on the AIB transport. A rapid reduction of the insulin activity in the incubation medium was found in the experiments with the diaphragm preparation but not in the experiments with the levator ani muscle. Insulin was found to cause a flux of water from the extracellular to the intracellular compartments in the diaphragm but not in the levator ani muscle. The results are discussed and it is concluded that the intact levator ani preparation is very suitable for further experiments concerning the mechanism of action of insulin.

EFFECT OF ACTINOMYCIN D ON TSH-INDUCED STIMULATION OF THYROIDAL PROTEIN SYNTHESIS IN THE RAT

1974 ◽  
Vol 77 (1) ◽  
pp. 64-70 ◽  
Author(s):  
Gustav Wägar
Keyword(s):  
Protein Synthesis ◽  
Actinomycin D ◽  
The Other ◽  
Leucine Incorporation ◽  
Short Term ◽  
Other Hand ◽  
Thyroid Glands ◽  
Translational Level ◽  
Stimulation Of

ABSTRACT Whether the short-term regulation of thyroidal protein synthesis by TSH occurs at the transcriptional or the translational level was tested by measuring the effect of actinomycin D (act D) on the TSH-induced stimulation of L-14C-leucine incorporation into the thyroidal proteins of rats. TSH was injected 6 h before the rats were killed. The thyroid glands were then removed and incubated in vitro in the presence of L-14C-leucine for 2 h. The pronounced stimulation of leucine incorporation in the TSH-treated animals was depressed as compared with controls but still significant even when the animals had been pre-treated with 100 μg act D 24 and 7 h before sacrifice. On the other hand, act D strongly decreased incorporation of 3H-uridine into RNA. Short-term regulation of thyroidal protein synthesis by TSH appears to be partly but not wholly dependent on neosynthesis of RNA. Hence regulation may partly occur at the translation level of protein synthesis.

scholarly journals Biosynthesis of growth hormone in the rat anterior pituitary gland. Stimulation of biosynthesis in vitro by insulin

1973 ◽  
Vol 134 (4) ◽  
pp. 1103-1113 ◽  
Author(s):  
A. Betteridge ◽  
M. Wallis
Keyword(s):  
Growth Hormone ◽  
Anterior Pituitary ◽  
Rna Synthesis ◽  
Glucose Utilization ◽  
Actinomycin D ◽  
Hormone Synthesis ◽  
Pituitary Glands ◽  
Hormone Biosynthesis ◽  
Stimulation Of

The effect of insulin on the incorporation of radioactive leucine into growth hormone was investigated by using rat anterior pituitary glands incubated in vitro. A 50% stimulation over control values was observed at insulin concentrations above 2μm (280munits/ml). The effect was specific for growth hormone biosynthesis, over the range 1–5μm-insulin (140–700munits/ml). Lower more physiological concentrations had no significant effect in this system. Above 10μm (1.4 units/ml) total protein synthesis was also increased. The stimulation of growth hormone synthesis could be partially blocked by the addition of actinomycin D, suggesting that RNA synthesis was involved. Insulin was found to stimulate the rate of glucose utilization in a similar way to growth hormone synthesis. 2-Deoxyglucose and phloridzin, which both prevented insulin from stimulating glucose utilization, also prevented the effect of insulin on growth hormone synthesis. If glucose was replaced by fructose in the medium, the effect of insulin on growth hormone synthesis was decreased. We conclude that the rate of utilization of glucose may be an important step in mediating the effect of insulin on growth hormone synthesis.

scholarly journals Attachment of the levator ani muscle extends to the superior ramus of the pubic bone through electrophysiological and anatomical examinations

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Hung-Yen Chin ◽  
Chih-Wei Peng ◽  
Ming-Ping Wu ◽  
Chih-Hwa Chen ◽  
Yu-Ting Feng ◽  
...  
Keyword(s):  
Pelvic Floor ◽  
Pelvic Pain ◽  
Chronic Pelvic Pain ◽  
Pelvic Floor Muscle ◽  
Levator Ani ◽  
Pubic Bone ◽  
Levator Ani Muscle ◽  
Cadaver Dissection ◽  
Inferior Border ◽  
Stimulation Of

AbstractMyofascial pelvic pain (MFPP) of pelvic floor muscles is a common cause of chronic pelvic pain (CPP). The pathological mechanisms and treatments of MFPP are complex and still unclear until now. The levator ani muscle (LAM) is the major pelvic floor muscle. The purpose of this study was to examine the fascia and attachment of LAM through the electromyogram (EMG) and cadaver dissection. Electrophysiological stimulation of the obturator fascia above the arcus tendinous levator ani (ATLA) could trigger contraction and electrophysiological changes in LAM insertion. The LAM of embalmed adult cadavers was examined especially in the area above the ATLA. Some skeletal muscle fibers were found above the ATLA within the obturator fascia and were confirmed by Masson’s trichrome section staining. Our electromyography (EMG) and anatomical data implied that the attachment of LAM aponeurosis extended beyond ATLA to the inferior border of the superior ramus of the pubic bone. The new discovered attachment of LAM could provide a reference position for clinical diagnosis and treatment of MFPP or CPP.

scholarly journals Some biochemical effects of triamcinolone acetonide on rat liver and muscle

1970 ◽  
Vol 116 (3) ◽  
pp. 349-355 ◽  
Author(s):  
R. F. Peters ◽  
M. C. Richardson ◽  
Margaret Small ◽  
A. M. White
Keyword(s):  
Amino Acids ◽  
Triamcinolone Acetonide ◽  
Time Course ◽  
Muscle Protein ◽  
Specific Radioactivity ◽  
Synthetic Activity ◽  
Tissue Homogenate ◽  
Glycogen Concentration

1. The powerful anti-inflammatory glucocorticoid triamcinolone acetonide, administered to rats at 20 and 2.5mg/kg, leads to a decrease in the incorporation in vivo of [3H]uridine and [32P]orthophosphate into hind-limb skeletal muscle. 2. At the higher dose, this decrease in the rate of incorporation of precursors into RNA precedes a decrease in the incorporating ability of muscle ribosomes, which commences about 4–5h after drug administration, but is unaccompanied by any changes in the concentration of tissue ATP or free amino acids. 3. The ribosomal dysfunction extends to polyribosomes, which can only be successfully isolated from the muscle of triamcinolone-treated animals after the addition of α-amylase to the tissue homogenate to remove glycogen. 4. The specific radioactivity of muscle protein labelled in vivo with 14C-labelled amino acids does not decrease progressively after triamcinolone administration. After 2h there is an apparent stimulation of incorporation which leads to an overall discrepancy between measurements of protein-synthetic activity made in vivo and in vitro. 5. There is a significant increase in muscle-glycogen concentration between 8 and 12h after the administration of triamcinolone acetonide (20mg/kg), although a significant decrease occurs after 4h. The fall in glycogen concentration may be due to a decrease in the rate of synthesis of protein essential for glucose uptake into the tissues. 6. As judged by (a) incorporation of 14C-labelled amino acids into protein, (b) [3H]uridine and [32P]-orthophosphate incorporation into RNA, (c) the rate of induction of tryptophan pyrrolase and (d) changes in the pool sizes of taurine and tryptophan, the responses in liver followed the same time-course as those in muscle after administration of the drug.

scholarly journals Steroidal Androgens and Nonsteroidal, Tissue-Selective Androgen Receptor Modulator, S-22, Regulate Androgen Receptor Function through Distinct Genomic and Nongenomic Signaling Pathways

2008 ◽  
Vol 22 (11) ◽  
pp. 2448-2465 ◽  
Author(s):  
Ramesh Narayanan ◽  
Christopher C. Coss ◽  
Muralimohan Yepuru ◽  
Jeffrey D. Kearbey ◽  
Duane D. Miller ◽  
...  
Keyword(s):  
Androgen Receptor ◽  
Intracellular Signaling ◽  
Molecular Mechanisms ◽  
Levator Ani ◽  
Reproductive Organs ◽  
Cross Reactivity ◽  
Levator Ani Muscle ◽  
Xenopus Laevis Oocyte ◽  
Muscle Weight

Abstract Androgen receptor (AR) ligands are important for the development and function of several tissues and organs. However, the poor oral bioavailability, pharmacokinetic properties, and receptor cross-reactivity of testosterone, coupled with side effects, place limits on its clinical use. Selective AR modulators (SARMs) elicit anabolic effects in muscle and bone, sparing reproductive organs like the prostate. However, molecular mechanisms underlying the tissue selectivity remain ambiguous. We performed a variety of in vitro studies to compare and define the molecular mechanisms of an aryl propionamide SARM, S-22, as compared with dihydrotestosterone (DHT). Studies indicated that S-22 increased levator ani muscle weight but decreased the size of prostate in rats. Analysis of the upstream intracellular signaling events indicated that S-22 and DHT mediated their actions through distinct pathways. Modulation of these pathways altered the recruitment of AR and its cofactors to the PSA enhancer in a ligand-dependent fashion. In addition, S-22 induced Xenopus laevis oocyte maturation and rapid phosphorylation of several kinases, through pathways distinct from steroids. These studies reveal novel differences in the molecular mechanisms by which S-22, a nonsteroidal SARM, and DHT mediate their pharmacological effects.

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