Biomedical subjects

R R Tremblay

Publications and source records attributed to R R Tremblay.

At least 73 records · Page 4Linked to original sources

PubMed1987

The major 40-kDa glycoprotein in human prostatic fluid is identical to Zn-alpha 2-glycoprotein.

A major 40-KDA protein secreted by human prostate was isolated from whole seminal plasma by sequential column chromatography on DEAE-Sepharose CL-6B, concanavalin A(Con A)-Sepharose, and Sephadex G-100. Although the purified preparation still contained minor contaminants, its amino acid composition was found to be identical to the one of a glycoprotein isolated previously from seminal plasma by Lin et al (1983). Antibodies against this protein were produced in rabbits and their use in immunoblotting experiments revealed the presence of the antigen in several tissues including the prostate, the liver, the heart, the kidney, the epididymis, and the testis. A radioimmunoassay confirmed these results and showed that blood serum concentrations of this protein were relatively high in men (81 +/- 3 micrograms/ml), women (68 +/- 3 micrograms/ml), and cord blood of newborns (32 +/- 1 micrograms/ml). The serum concentrations of this protein along with its physicochemical characteristics suggested that it could be identical to Zn-alpha 2-glycoprotein, a human serum protein previously isolated by Burgi and Schmid (1961). This hypothesis was confirmed by a double immunodiffusion analysis using a commercial anti-Zn-alpha 2-glycoprotein antiserum. Finally, in vitro translation of prostatic poly(A) + RNA in rabbit reticulocyte lysate in the presence of canine pancreatic microsomal membranes resulted in the formation of an immunoprecipitable 42-kDa band. These results show that Zn-alpha 2-glycoprotein can be synthesized in the prostate itself. The demonstration of high concentrations of this protein in prostatic tissue and prostatic secretion should facilitate the elucidation of its role in the prostate and in other tissues.

Amino Acids↗

PubMed1987

Lack of effect of anabolic steroids on specific mRNAs of skeletal muscle undergoing compensatory hypertrophy.

Compensatory hypertrophy of the fast-twitch plantaris muscle (HP) was induced in male rats to determine whether the resulting translational activity of isolated polyribosomes could be modified in this process and by the androgen status. HP induced a significant increase in free androgen binding sites and a typical protein synthesis pattern characterized by a slow myosin light chain isozyme (LC-1S), an increase in fast isozymes (LC-1F,2F) and of beta-tropomyosin/alpha-tropomyosin ratio. The variations in receptor occupancy following castration and treatments with four anabolic steroids (AS) did not result in modification of the template activity of major HP mRNAs. These data suggest that the slight increase of steroid receptors found in HP remains insufficient to trigger an androgenic response in skeletal muscle.

Anabolic Agents↗

PubMed1987

Purification of ram seminal plasma acid alpha-glucosidase.

1. Ram seminal plasma alpha-glucosidase has been purified in order to increase our knowledge of this enzyme and of its role in epididymal physiology. 2. Since the enzyme behaved differently from other known acid alpha-glucosidases and was not affinity-adsorbed on dextran gels, another approach had to be used. 3. The final procedure included an ethanol precipitation step, sequential chromatography on hydroxylapatite and DEAE Sepharose CL-6B, isoelectric focusing in polyacrylamide gels and ultrafiltration. 4. The resulting purification factor of alpha-glucosidase was 9822 with an overall yield of 5%. 5. The purified material consisted of several isoforms with a mol. wt of 105,000 and isoelectric points varying between 4 and 5.

Animals↗

PubMed1987

Plasma levels of C-19 steroids and 5 alpha-reduced steroid glucuronides in hyperandrogenic and idiopathic hirsute women.

In the present study, the authors measured the plasma levels of unconjugated and glucuronide (G) derivatives of C-19 steroids in hirsute women divided into two groups, depending upon their dehydroepiandrosterone sulfate (DHEAS). This quite restrictive classification was the result of an arbitrary decision of the authors, who wanted to focus interpretation of their data on DHEAS, the well-known adrenal androgen. In the hyperandrogenic hirsute woman (HH), the DHEAS levels were higher than 3.0 micrograms/ml; in idiopathic hirsute women (IH), values of DHEAS were comparable to those observed in normal women (1.2 to 2.5 micrograms/ml). In the HH group, the levels of dehydroepiandrosterone, androstenedione, androst-5-ene-3 beta,17 beta-diol (delta 5-diol), testosterone, dihydrotestosterone (DHT), androstane-3 alpha, 17 beta-diol (3 alpha-diol), androstane-3 beta,17 beta-diol (3 beta-diol), androsterone (ADT), DHTG, 3 alpha-diol-G, 3 beta-diol-G, and ADTG were higher than the normal range whereas, in the IH group, only delta 5-diol, DHT, 3 beta-diol-G and ADTG were elevated. These data are compatible with the hypothesis that the plasma levels of steroid G represent the peripheral formation of androgen in target tissues. Because the pattern of androgen metabolism is most probably changed in many cases of hirsutism, these data suggest that for research purposes, it would be preferable to measure 3 beta-diol-G and ADTG in addition to 3 alpha-diol-G in order to gain additional information concerning androgen metabolites in this disorder.

Adolescent↗

PubMed1987

Immunohistochemical localization of a prostatic secretory protein of 94 amino acids in normal prostatic tissue, in primary prostatic tumors and in their metastases.

Using the immunoperoxidase technique, we have studied in normal, hyperplastic and adenocarcinomatous prostates the tissue localization of an abundant 94 amino acid protein secreted by prostatic epithelial cells. In normal and hyperplastic prostates, strong immunoreactivity was found exclusively in glandular epithelial cells. No reaction was observed over the stroma. In well differentiated adenocarcinoma, the acinar cells were generally stained less intensely than in benign prostatic hyperplasia while in poorly differentiated tissue, strongly positive immunoperoxidase staining was found in some cancer cells scattered in the stroma. All prostatic cancer tissues examined (N = 21), with the exception of one, exhibited at least a few positive immunoreactive areas for the 94 amino acid secretory protein. In addition, immunoperoxidase staining was observed in lung and bone marrow metastases respectively in two patients with prostatic carcinoma. All other normal tissues and non-prostatic cancers studied to date were negative. These results suggest that this new marker could be a useful addition to prostatic acid phosphatase and prostate specific antigen.

Adenocarcinoma↗

PubMed1987

Regulation of carbonic anhydrase III by thyroid hormone: opposite modulation in slow- and fast-twitch skeletal muscle.

This laboratory previously reported that a major 30 kilodalton (kDa) protein of the soluble cytoplasmic fraction of the rat slow-twitch soleus muscle is modulated by thyroid hormone. This protein has been purified and a portion of the primary structure has been determined. The sequence analysis suggested that the 30-kDa protein is carbonic anhydrase III (CA III; EC 4.2.1.1). The reaction of the protein with a CA III specific antibody and the similar modulation of CA III by thyroid hormone also support this conclusion. Immunochemical quantification of CA III and measurement of CA activity were performed in skeletal muscles of defined fiber-type composition from rats that were rendered hyperthyroid by treatment with 3,3',5-triiodo-L-thyronine. These experiments revealed that CA activity and CA III content are deinduced in the soleus muscle (primarily type I fibers) and induced in the superficial vastus lateralis muscle (primarily type IIb), whereas no changes were detected in the tibialis anterior muscle (primary type IIa). These results show that the modulation of CA III by thyroid hormone in rat skeletal muscle is not limited to the slow-twitch soleus muscle and that the amplitude and direction of this modulation are directly related to the initial fiber-type composition of the skeletal muscle.

Amino Acid Sequence↗

PubMed1987

In vitro translation of human prostatic acid phosphatase mRNA and processing of the translation products by microsomal membranes and endoglycosidase H.

Poly(A)+ RNA was isolated from human prostatic tissue and translated in vitro in a rabbit reticulocyte lysate translation assay. Acid phosphatase labeled with [35S]methionine was immunoprecipitated with an antibody against seminal plasma acid phosphatase. Two-dimensional polyacrylamide gel electrophoresis of the immunoprecipitate, followed by fluorography, revealed the presence of two spots (one major and one minor), both having a molecular mass of 43 kilodaltons (kDa) and an isoelectric point higher than mature acid phosphatase. Addition of canine pancreatic membranes to the translation assay resulted in the formation of four immunoprecipitable spots with molecular masses ranging from 43 to 49 kDa on one-dimensional gels. These spots probably represent acid phosphatases containing one to four core sugar groups, since after the addition of endoglycosidase H the molecular mass heterogeneity was abolished and we observed only one major band with a molecular mass (41 kDa) slightly lower than the ones of the primary translation product. These results suggest that human prostatic acid phosphatases are synthesized as two 43-kDa preproteins, which are further processed to 41-kDa proteins by removal of their signal peptide. Heterogeneity of the native protein arises mostly from glycosylation at four sites and not from differences in the amino acid sequence of the various forms.

Acetylglucosaminidase↗

PubMed1987

The influence of immobilization stress on cardiac protein synthesis. A possible regulatory role for glucocorticoids.

High serum corticosterone levels and transient depletion of cytosolic glucocorticoid receptor binding capacity were observed in rat cardiac muscle following immobilization stress. To evaluate the effect of this treatment on the protein synthetic capacity, biologically active polyribosomes were used to direct the in vitro synthesis of polypeptides in the rabbit reticulocyte lysate. The results of these experiments indicate that the template activity of several messenger RNAs coding for major myofibrillar proteins was increased. This change in protein synthetic activity was not observed in adrenalectomized animals. Collectively, these results suggest that glucocorticoids are involved in the regulation of cardiac protein biosynthesis.

Adrenalectomy↗

PubMed1986

Proteolytic activity of arginine esterase from dog seminal plasma towards actin and other structural proteins. Comparison with trypsin and kallikrein.

At equimolar ratio of enzyme/substrate, actin, tropomyosin, fibronectin and myosin were extensively hydrolyzed during an incubation of one hour at 37 degrees C. Dog serum albumin, ovalbumin, bovine gamma-globulin and human prostatic acid phosphatase were not hydrolyzed. The activity of arginine esterase towards actin at pHs 6.5, 7.1 and 7.6 was respectively 60, 74 and 84% of the one found at optimum pH 8.2. The cleavage products of actin by arginine esterase and trypsin were similar although trypsin activity was 5000-fold higher. Kallikrein produced a major fragment of actin not observed with arginine esterase and trypsin. It is concluded that arginine esterase has a low trypsin-like activity towards structural proteins and that this activity may have a physiological significance.

Actins↗

PubMed1986

Treatment of hirsutism with spironolactone.

The discovery of compounds possessing antiandrogenic activities has led to their utilization in the treatment of hirsutism of various aetiologies. Spironolactone generally lowers the plasma testosterone by altering its formation and metabolism as well as by decreasing its blood production rate; the medication also contributes to increase the peripheral conversion of testosterone to oestradiol. A major action is that spironolactone inhibits androgen binding to receptor molecules in the cytosol or the nucleus of target tissues such as the skin. During the last five years, we have studied over 450 cases of hirsutism. Approximately 80% of these women were treated with spironolactone alone or in association with dexamethasone (2.5%) or an oral contraceptive (15%). Hirsutism was classified according to Lorenzo (1970). Good to very good clinical results were observed in 80% of the patients who were under study for a minimum of 3 to 4 years. Adverse side-effects were recorded in less than 5% of our group of patients. On the basis of our data and our clinical experience, we conclude that spironolactone is an effective drug in the treatment of female hirsutism.

17-alpha-Hydroxyprogesterone↗

PubMed1986

Origin of alkaline phosphatase of canine seminal plasma.

The tissular origin of alkaline phosphatase was evaluated in canine seminal plasma. Alkaline phosphatase activity was most concentrated in the first fraction of the split ejaculate and was virtually undetectable in the third and fourth fractions. By contrast, arginine esterase, a known marker of dog prostatic secretion, was present in similar concentrations in all fractions of the split ejaculates analyzed by SDS gel electrophoresis. Similarly, arginine esterase was very abundant in secretory granules prepared from dog prostate homogenates, whereas these granules contained virtually no alkaline phosphatase. Among male sex accessory organs, alkaline phosphatase activity was very high in the epididymis and much lower in the testis and prostate. Furthermore, the specific activity in epididymal fluid collected from the cauda epididymis was about 10 times higher than in the corresponding epididymal homogenates. These results show that the major portion of alkaline phosphatase in dog seminal plasma does not come from the prostate but from the epididymis.

Alkaline Phosphatase↗

PubMed1986

Variations of glucocorticoid receptors in intact or denervated muscles: lack of cause-effect relationship with muscle atrophy in the rat.

The process of muscular atrophy following denervation has been tentatively ascribed to the influence of glucocorticoids (G) because of the rapid increase of cytosolic G receptors (RG) after sciatic nerve section. It appears however that the level of muscular atrophy is similar: in slow or fast-twitch muscles in spite of huge variations in RG; in intact or adrenalectomized (ADR-X) rats. Moreover, the protein muscle profile of intact of ADR-X rats after gel electrophoresis is similar but drastically decreased after 3 weeks of denervation. We conclude that there is no cause-effect relationship between muscle atrophy and RG elevation after nerve section.

Adrenal Glands↗

PubMed1986

Radioautographic localization and regulation of the insulin receptors in rat testis.

Luteinizing hormone (LH) is involved in maintenance of the insulin receptor in rat Leydig cells. In the cryptorchid model, spontaneous LH elevation increases insulin binding in Leydig cell membrane; this result is confirmed by the number of insulin receptors determined by radioautography. Administration of testosterone or LH-RH to control or cryptorchid rats lower insulin binding in testis membranes indicating the key role of LH. Isolated Leydig cells respond in vitro to LH by increasing their insulin binding. Localization and specificity of this binding has been studied by radioautography and we have demonstrated the preferential localization of insulin receptor in Leydig cells vs tubular cells. We conclude that insulin plays a synergistic role with LH on steroidogenesis via a specific membrane receptor which number appears modulated by pituitary LH.

Animals↗

PubMed1986

Dog prostate arginine esterase is related to human prostate specific antigen.

We have analyzed prostatic proteins of canine and human seminal plasma. We have compared in particular the physicochemical characteristics of arginine esterase from dog to those of the prostatic specific antigen from man. Both are major secretory proteins in each species. Arginine esterase and prostate specific antigen are related enzymes belonging to the serine-protease class. Their enzymatic activity towards protein substrates appears similar. However their activity towards synthetic substrates indicate that arginine esterase is a trypsin-like enzyme whereas prostate specific antigen has some chymotrypsin-like activity. The canine enzyme is inhibited by phenylmethylsulfonyl fluoride while the human one is not. The amino acid sequence of a portion of the NH2-terminal of the 2 proteins share 58% homology. Their molecular weights are similar: 29 KDa for arginine esterase and 34 KDa for prostate specific antigen. These results show that arginine esterase and prostate specific antigen are distinct but closely related proteins. These results strongly suggest that the dog could be an excellent model for the elucidation of the presently unknown role of this class of abundant enzymes of prostatic origin.

Amino Acid Sequence↗

PubMed1985

Enzymatic characterization of arginine esterase from dog seminal plasma.

Previously purified arginine esterase from dog seminal plasma was characterized enzymatically. The enzyme was found to have a rather narrow specificity for arginine esters, much less for lysine esters and was practically devoid of activity towards tyrosine esters, casein, albumin and azocoll. It had a broad optimum pH between 8 and 9. It presented no kallikrein-like activities either in the blood pressure test in dog or in the rat uterus contraction test. It was inhibited by bovine pancreas trypsin inhibitor, aprotinin, phenylalanylprolyl arginine chloromethyl ketone, diisopropylfluorophosphate, phenylmethylsulfonyl fluoride, sodium dodecyl sulfate and leupeptin, but not by soybean trypsin inhibitor, tosyllysine chloromethyl ketone, tosylamide-2-phenylethyl chloromethyl ketone, iodoacetamide, Triton X-100 and EDTA. Experiments involving incubation of prostatic cytosol with purified arginine esterase showed that actin was the only important prostatic protein that was extensively hydrolyzed by this enzyme. It is not known presently whether the hydrolysis of actin is related to a true physiological function of the enzyme and whether actin and arginine esterase ever come into contact with each other in vivo. These properties indicate that arginine esterase from dog seminal plasma is different from other known proteinases including classical kallikreins, although it presents many similarities with this class of enzyme.

Animals↗

PubMed1985

Modulation of a major 30-kDa skeletal muscle protein by thyroid hormone.

Thyroidectomy results in the transformation of type II fibres to type I in rat soleus muscle. In vitro translations containing polyribosomes indicate that the template activity of mRNA coding for a 30-kDa protein is increased in hypothyroid (6 months) rats. The cellular content of this protein is also increased in hypothyroid rats. The in vitro synthesis of the 30-kDa protein is not observed in thyroidectomized (10 weeks) rats that have been treated with triiodothyronine. The synthesis and accumulation of this protein are directly related to the proportion of type I fibres in rat skeletal muscle and appear to be modulated by thyroid hormone.

Animals↗

PubMed1985

Effect of physiological (in lamb) or drug-induced (in adult) immaturity of ram spermatozoa on seminal plasma alpha-glucosidase activity.

We have been able to collect ejaculates from four pre-pubertal Finnish Landrace and Suffolk lambs. Respective seminal plasma alpha-glucosidase specific activity was low (less than 0.3 mU/mg) whatever the season of observation. At puberty, it reached a level higher than 1 mU/mg as observed in adult rams. Administration of alpha-chlorohydrin to 14 adult rams (25 mg/kg/day during 25 days) led to the appearance of immature sperm. Seminal plasma alpha-glucosidase activity dropped from 1.5 to 0.5 mU/mg in both breeds, while fructose was raised from 2 to 6 mg/ml. L-carnitine and blood plasma testosterone remained unchanged during treatment. Semen characteristics appeared normal one month after the end of treatment when fructose concentration decreased simultaneously and enzymatic activity increased during two months to normal levels. The present findings suggest that seminal plasma alpha-glucosidase may be considered as a useful epididymal marker in ram.

Animals↗

PubMed1985

Protein phenotype and gene expression in the rat perineal levator ani muscle.

The rat perineal levator ani (LA) and bulbocavernosus (BC) muscles are homogeneously type 2B fibers as determined by Ca, Mg-ATPase activity. The LA and extensor digitorum longus (EDL) muscles contain similar quantities of creatine kinase and several glycolytic enzymes despite significant differences in fiber composition. The LA muscles synthesizes and accumulates only the fast isoforms of protein C, myosin heavy chain and myosin light chains.

Animals↗