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.

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.

COMPARISON OF THE STIMULATORY EFFECTS OF OVINE, PORCINE AND HUMAN FOLLICLE-STIMULATING HORMONE AND OF OVINE AND HUMAN LUTEINIZING HORMONE ON THE ACCUMULATION OF CYCLIC AMP BY PORCINE GRANULOSA CELLS

1979 ◽  
Vol 80 (1) ◽  
pp. 9-20 ◽  
Author(s):  
ADA M. LINDSEY ◽  
CORNELIA P. CHANNING
Keyword(s):  
Cyclic Amp ◽  
Granulosa Cells ◽  
Incubation Medium ◽  
Follicle Stimulating Hormone ◽  
Similar Response ◽  
Intracellular Accumulation ◽  
Porcine Granulosa Cells ◽  
Tenfold Increase ◽  
Incubation Periods

The effects of ovine, porcine and human FSH, and ovine and human LH on the accumulation of cyclic AMP by porcine granulosa cells obtained from follicles at various stages of maturation were investigated. During incubation periods of 15 min, 10 μg ovine FSH pretreated with antiserum to LH or 10 μg human FSH resulted in an 11- to 18-fold, five-to ninefold, and less than a twofold increase in intracellular accumulation of cyclic AMP by granulosa cells from small (1–2 mm), medium (3–5 mm) and large (6–12 mm) follicles respectively. Similar patterns of response occurred with addition of porcine FSH. After incubation for 30 and 60 min with ovine, porcine or human FSH, significant accumulation of cyclic AMP in the incubation medium occurred with cells obtained from small and medium-sized follicles. After 60 min of incubation with FSH the accumulation of cyclic AMP in the incubation medium exceeded the intracellular cyclic AMP levels in granulosa cells from small and medium-sized follicles. During incubation periods of 15 min, 1·0 μg ovine LH resulted in less than a twofold, a fourfold and greater than a tenfold increase in intracellular accumulation of cyclic AMP by granulosa cells from small, medium and large follicles respectively. Addition of human LH brought about a similar response. Incubation periods of 30 and 60 min with 1·0 μg ovine or human LH resulted in significant accumulation of cyclic AMP in the incubation medium by granulosa cells from large follicles; cyclic AMP content in the incubation medium was greater after 60 min compared with 30 min of incubation. It was concluded that ovine FSH pretreated with an antiserum to LH had similar effects on cyclic AMP levels as did purified human and porcine FSH, and that the stimulatory effects of the less pure ovine FSH were probably not due to an impurity in the FSH preparation. Porcine granulosa cells obtained from small follicles should be suitable as an in-vitro FSH bioassay while granulosa cells obtained from large follicles should be suitable as an in-vitro LH bioassay.

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.

PHARMACOLOGICAL PROPERTIES OF NANDROLONE DECANOATE

1960 ◽  
Vol XXXV (III) ◽  
pp. 405-412 ◽  
Author(s):  
J. de Visser ◽  
G. A. Overbeek
Keyword(s):  
Levator Ani ◽  
Female Rats ◽  
High Dose ◽  
Levator Ani Muscle ◽  
List Type ◽  
Pharmacological Properties ◽  
Nandrolone Decanoate ◽  
Anabolic Activity ◽  
Male And Female Rats ◽  
Dose Levels

ABSTRACT 1. The pharmacological properties of nandrolone decanoate (= caprinate), by abbreviation nor-A. D., have been studied. 2. Nor-A. D. has a marked, long-lasting effect on the levator ani muscle of the castrated rat, but it has little activity on the seminal vesicles and prostate. 3. Nor-A. D. displays only weak gonad inhibiting properties in male and female rats. 4. The anti-oestrogenic activity is low. 5. At high dose levels the anabolic activity becomes maximal and the other effects become evident. The same can be expected to occur if injections are administered with too great a frequency. 6. Chronic toxicity studies in rats and dogs demonstrate its lack of toxicity.

Noradrenergic stimulation of serotonin release from rat pineal glands in vitro

1987 ◽  
Vol 114 (1) ◽  
pp. 3-9 ◽  
Author(s):  
V. J. Aloyo ◽  
R. F. Walker
Keyword(s):  
Serotonin Release ◽  
Time Interval ◽  
Intracellular Accumulation ◽  
Differential Distribution ◽  
Intracellular Compartments ◽  
5 Ht Uptake ◽  
Layer Chromatography ◽  
Adrenergic Terminals ◽  
Stimulation Of

ABSTRACT The pharmacodynamics of serotonin (5-hydroxytryptamine; 5-HT) uptake and release were studied in rat pineal glands. Initially, uptake was tested by incubating pineals with several concentrations of [3H]5-HT. The incubation media also contained [14C]mannitol to which cells are impermeable. Since [14C]mannitol accumulates only in extracellular spaces, the radio-labelled sugar was used to determine the differential distribution of [3H]5-HT in pineal compartments. Intracellular accumulation of 3H in pineal glands increased linearly as a function of time for [3H]5-HT concentrations ranging from 1 to 10 μmol/l. The ratio of 3H to 14C also increased for the same time-interval, indicating that the glands accumulated [3H]5-HT preferentially in non-extracellular spaces. [3H]5-HT accumulated in pineal glands which were denervated for more than 7 days before testing, suggesting that uptake is not restricted to adrenergic terminals but also occurs in pinealocytes. In addition to uptake, spontaneous and noradrenaline-stimulated release of [3H]5-HT was tested in perifusion and/or step-transfer systems. Spontaneous release of [3H]5-HT was biphasic consisting of rapid and slower efflux phases. In contrast, release of [14C]mannitol was monophasic, characterized exclusively by rapid efflux. Since [14C]mannitol does not enter cells, the rapid and slower phases of [3H]5-HT efflux may represent release from pineal extracellular and intracellular compartments respectively. The identity of [3H]5-HT in pineal glands and perifusion media was confirmed by thin-layer chromatography. When l-noradrenaline was added to the perifusion media, [3H]5-HT efflux during the slower phase of release was significantly increased above the non-stimulated state. In contrast, d-noradrenaline was significantly less effective than l-noradrenaline in releasing [3H]5-HT. Noradrenaline also stimulated [3H]5-HT release from denervated glands, suggesting that pinealocytes secrete 5-HT in response to noradrenergic signals. Since the pineal is innervated by fibres of the sympathetic division of the autonomic nervous system, differential release of 5-HT may occur in response to changing levels of glandular noradrenaline. J. Endocr. (1987) 114, 3–9

Actin and creatine kinase mRNAs in rat levator ani and vastus muscles as a function of androgen status

1990 ◽  
Vol 68 (4) ◽  
pp. 1548-1561 ◽  
Author(s):  
G. Boissonneault ◽  
P. Chapdelaine ◽  
R. R. Tremblay
Keyword(s):  
Creatine Kinase ◽  
Vastus Lateralis ◽  
Control Level ◽  
Levator Ani ◽  
In Vitro Translation ◽  
Levator Ani Muscle ◽  
Time Intervals ◽  
Actin Expression ◽  
Fast Twitch

The plasticity of two selected mRNAs was studied in two typical fast-twitch muscles at different time intervals after orchiectomy (GDX). The levator ani muscle of the rat (LA) is exquisitely sensitive to androgens, whereas the superficial vastus lateralis (SVL) lacks such sensitivity. In vitro translation of RNA isolated from both tissues indicated that actin was among the most repressed proteins of the LA at day 10 postsurgery (GDX-10 days), whereas the template activity of the SVL mRNAs remains virtually unmodified. We used an available actin cDNA and demonstrated that the expression of the LA actin message is reduced by 85% in GDX-10 days and can be recovered after testosterone propionate (TP) injections (GDX + TP). In contrast, the actin expression in SVL remains constant up to day 20 postsurgery. In the LA, the expression of creatine kinase (CK) mRNA was increased 140% in GDX-5 days and decreased 34 and 17% in GDX-10 days and GDX-20 days, respectively, although the measured CK activity, as well as the in vitro translation of the message, remained elevated in those two latter groups. Control level of the CK mRNA expression was recovered in the GDX + TP group. Again, the expression of the message was unchanged in SVL, suggesting that the protein synthesis of this skeletal muscle is far less sensitive to androgen deprivation than that of the LA muscle.

COMPARISON BETWEEN THE BINDING OF 19-NORTESTOSTERONE, 5α-DIHYDROTESTOSTERONE AND TESTOSTERONE IN RAT PROSTATE AND BULBOCAVERNOSUS/LEVATOR ANI MUSCLE

1976 ◽  
Vol 70 (3) ◽  
pp. 379-387 ◽  
Author(s):  
M. KRIEG ◽  
M. DENNIS ◽  
K. D. VOIGT
Keyword(s):  
Specific Binding ◽  
Levator Ani ◽  
Levator Ani Muscle ◽  
Binding Affinities ◽  
Receptor Sites ◽  
Rat Prostate ◽  
Layer Chromatography ◽  
In Vitro Data

SUMMARY Specific binding of [3H]19-nortestosterone in the 100000 g cytosol of the rat bulbocavernosus/levator ani muscle (BCLA) and prostate was demonstrated by agargel electrophoresis at low temperature and compared qualitatively and quantitatively with the binding of tritiated testosterone and 5α-dihydrotestosterone (5α-DHT). Both tissues showed a greater binding affinity for 5α-DHT than for 19-nortestosterone, with testosterone binding the least well of the three. The relative binding affinities in the BCLA and prostate were: 19-nortestosterone: testosterone = 1·4, 19-nortestosterone: 5α-DHT = 0·7. The differences were statistically significant (P < 0·02). The concentrations of receptor sites for 5α-DHT were 171 ± 20 (s.d.) fmol/mg prostatic cytosol protein and 24 ± 4 (s.d.) fmol/mg BCLA cytosol protein. The in-vitro metabolism of the three steroids in both tissues was also investigated by thin-layer chromatography. After incubating for 2 h at 0 °C the prostate was shown to reduce 26% of the 5α-DHT to androstanediols whilst the BCLA showed a 5% conversion. Testosterone was converted by the prostate to 5α-DHT (10%) and the androstanediols (6%) whilst the BCLA showed little activity in this respect. Comparing these in-vitro data with in-vivo findings from the literature, in both organs there is a positive correlation of the extent of binding in vitro to the stimulation of growth in vivo, bearing in mind that testosterone is metabolized to 5α-DHT in the prostate whilst in the BCLA, 5α-reductase is essentially absent.

DIFFERENTIAL EFFECTS OF CASTRATION AND DENERVATION ON PROTEIN SYNTHESIS IN THE LEVATOR ANI MUSCLE OF THE RAT

1972 ◽  
Vol 54 (1) ◽  
pp. 3-NP ◽  
Author(s):  
M. BUREŠOVÁ ◽  
E. GUTMANN ◽  
V. HANZLÍKOVÁ
Keyword(s):  
Protein Synthesis ◽  
Levator Ani ◽  
Mature Male ◽  
Male Rats ◽  
Levator Ani Muscle ◽  
Female Rat ◽  
Weight Changes ◽  
Immature Male ◽  
Testosterone Administration

SUMMARY The effects of testosterone on weight changes, incorporation of labelled precursors into RNA and proteins, and on ultrastructure of the levator ani muscle of male rats in which castration or denervation was performed, were studied. No increase of weight occurred in the denervated levator ani muscle after castration. There was no increase in the incorporation of labelled precursors into RNA and proteins in vitro in mature rats, if the muscle was denervated. However, incorporation still increased when denervation was performed in sexually immature animals. The levator ani muscle, which normally undergoes postnatal involution in the female rat, could be maintained even after postnatal denervation if testosterone was administered at birth, the hormone acting as a nerve-independent trophic agent. The increase of protein synthesis in the levator ani of mature, male, castrated animals, induced by testosterone administration, was abolished after denervation of the muscle. The activating influence of testosterone upon protein synthesis was, however, still present in immature male animals.

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