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M Tóth

Publications and source records attributed to M Tóth.

At least 181 records · Page 10Linked to original sources
PubMed1978

A quantitative evaluation of the effect of testosterone on RNA metabolism in the seminal vesicle of the rat.

Androgen dependent gross changes in RNA concentration of the androgen responsive cells of rat seminal vesicle were monitored by measuring RNA/DNA ratios. The time course of the changes in the RNA/DNA ratio following castration and after replacement of testosterone obeys the predictions of a kinetic model which permits determination of the rate constants for RNA degradation separately for the state of withdrawal and replacement of testosterone. For both states the apparent rate constant for RNA degradation was found to be 0.4 day-1/t1/2 approximately or equal to 1.8 days). The rate constant was shown to be independent of the testosterone dose applied. The testosterone-induced increase in the RNA/DNA ratio could be prevented by the administration of Actinomycin D. These findings are consistent with the view that testosterone controls the RNA level in vesicular target cells through the regulation of the rate of RNA synthesis. The results indicate that the rate of RNA synthesis in the vesicular cells of castrated rats is a regular hyperbolic function of the dose of testosterone propionate administered to these rats. On the basis of this finding a new approach to the accurate determination of the relative androgenicity of androgenic steroids is suggested.

Animals↗
PubMed1977

Characterization of the cytoplasmic androgen receptor of rat seminal vesicle.

Postmitochondrial supernatant (PMS) (1) has been prepared from the homogenate of rat seminal vesicles and the characteristics of the binding reaction of 5alpha-dihydrotestosterone (DHT) to the cytoplasmic androgen receptor have been studied using a charcoal adsorption procedure. At 0 degrees C apparent equilibrium of binding is reached between 60 and 90 min of incubation but no exchange of bound (3H)DHT can be observed in the presence of a 100-fold excess of unlabelled DHT. Saturation analysis shows a single class of independent binding sites for DHT with an apparent dissociation constant of 1 nM at 0 degrees C and 2 nM at 25 degrees C. Concentration of binding sites is in the range of 25-80 fmoles/mg protein. When not occupied by DHT the receptor molecules are inactivated spontaneously following first order reaction kinetics. A rate constant of 0.27 hours-1 at 0 degrees C was determined for the inactivation reaction. In the (3H)DHT-binding reaction testosterone and 19-nortestosterone are even more efficient competitors than unlabelled DHT, while hydrocortisone does not compete at all. On the other hand significant binding of (3H) testosterone could not be demonstrated. The (3H)DHT-receptor complex is precipitated from the cytosol by 0 to 33% saturation of ammonium sulphate and sediments as a single, 3.1 S peak in sucrose gradients prepared in 0.4 M NaCl.

Adsorption↗
PubMed1977

[Clinical aspects of urethral diverticula].

Experience with the treatment of 39 cases of urethral diverticula between the years 1954 and 1974 is reported. The patients were 32 women and 7 men. In 7 cases (3 women and 4 men) the condition was congenital in origin. In 30 patients the first symptoms appeared between the 31st and 60th year. In a 12 months old infant a hazelnut sized diverticulum in the posterior urethra caused complete ischuria. In two-third of the patients symptoms of cystitis dominated, dyspareunia in women (8%) and prostatitis in men (16%) had a lower incidence. 80% of the diverticula were infected; they contained stones in 3 cases. In one case the diverticulum recurred and histology revealed in its wall a planocellular carcinoma. Thirty-five patients were subjected to operation. Postoperative fistula developed in 3 cases which had to be re-operated. In cases of recurring urethritis, cystitis and prostatitis, urography is recommended, since the symptoms might be due to the presence of urethral diverticula.

Adolescent↗
PubMed1977

Studies of the sensitivity and reproducibility of pharmacopoeial pyrogen testing.

Rabbits generally numbering 27 or 36 in each experiment were injected in 1970 with doses of the pyrogenic preparation Pyrago (HUMAN) and in 1971-72 and 76 with doses of the International Pyrogen Standard (I.P.St.). The maximum temperature rises were registered, randomized and interpreted according to the requirements of the BP, USP, P. Hung. and P. Nord. 0.29 degrees C mean temperature rises proved to be non-pyrogenic according to BP and P. Hung; whereas according to the USP and P. Nord. in some percents 'to be rejected' qualifications were also established. At more increasing mean temperature rises 0.49 degrees C and 0.58 degrees C, increasing pyrogenic and decreasing 'passable' qualifications were obtained. Beginning with 0.70 degrees C and at 0.86 degrees C and 1.08 degrees C, 'passable' groups disappeared. Exclusion of the rabbits showing low sensitivity (before randomization) barely influenced the results with 3.5 ng kg-1 I.P.St. in the experiment in which the mean temperature rise was 0.49 degrees C. If, however, the mean temperature rise was higher (0.57 degrees C or 0.69 degrees C), such a selection practically resulted in the disappearance of 'passable' qualifications in the triplet groups and a great predominance of 'to be rejected' qualifications in the large groups.

Animals↗
PubMed1977

Studies on the binding of androgens to the cytosol proteins and nuclei of the rat seminal vesicle.

Mince of the seminal vesicles of rats castrated 5--6 days before the experiment was incubated at 37 degree C with 3H-testosterone. Ater 60 min incubation with 10 nM testosterone 73% of the label bound to cytosol proteins and 83% of the label attached to nuclei was in 5alpha-dihydrotestosterone while unbound steroids contained only 29% dihydrotestosterone. The amount of dihydrotestosterone bound to cytosol proteins and nuclei was 0.4 pmol/g tissue and 1 pmol/g tissue, respectively. On the basis of the nuclear binding of this steroid about 1900 binding sites per nucleus were calculated. Both cytosolic and nuclear binding sites were half saturated at about 1 nM testosterone concentration. Most of the binding to cytosol proteins occurred during the first 10 min, while the maximum binding to nuclei was attained after 40 min of incubation. Nuclei were found to bind considerable amounts of testosterone. Binding of testosterone to nuclei reached its maximum between 10--20 min of incubation and declined then to a comparatively low level during the ensuing 40--50 min. Various experimental results suggest that testosterone and dihydrotestosterone are accumulated in the nuclei by independent mechanisms.

Animals↗
PubMed1976

Studies with the International Pyrogen Standard on the sensitivity and reproducibility of pharmacopoeial pyrogen testing.

Rabbits, 27 or 36 in each experiment, were injected with the International Pyrogen Standard (I.P.St.) in different seasons. The maximum temperature rises were registered, randomized and interpreted according to the requirements of the B.P. (1973), U.S.P. (1970), P. Hung. (1970) and P. Nord. (1962). Although the dose of 3.5 ng kg(-1) I.P.St. proved to be non-pyrogenic as tested in summer, when tested in winter the same dose was qualified pyrogenic (to be rejected) by up to one third of the combinations by the criteria of the four Pharmacopoeias. In the spring experiment "to be rejected" qualifications predominated as based on the response of large groups of rabbits. Exclusion of the rabbits showing low sensitivity (before randomization) barely influenced the results with 3.5 ng kg(-1) I.P.St. in the experiment in which the mean temperature rise was 0.49 degrees. If, however, the mean temperature rise was higher (0.57 or 0.69 degrees), such a selection practically resulted in the disappearance of "passable" qualifications in the triplet groups and a great predominance of "to be rejected" qualifications in the larger groups. The dose 7.0 ng kg(-1) consistently proved to be pyrogenic in large groups of rabbits.

Animals↗
PubMed1975

Inhibitory effect of prostaglandin E2 on the incorporation of 3H-thymidine into the DNA of thymus cells.

When rat thymic cells suspended in a simple salt-glucose-albumin medium were incubated with 10 mug/ml Prostaglandin E2 (PGE2) an inhibition of incorporation of 3H-thymidine into DNA was observed. PGE1 had a similar effect, while PGB2 and arachidonic acid proved to be ineffective. This inhibitory effect of PGE2 could be detected after a lag period of about 30 min but in the second hour of incubation the rate of incorporation of 3H-thymidine decreased to about 60 per cent of the control value. The extent of inhibition was found to be proportional to the log10 of the PGE2 concentration. Autoradiography showed that PGE2 had no influence on the number of DNA synthesizing cells. As an effect of PGE2 an early transient increase in the labeling of thymidine triphosphate was observed while the levels of labeled thymidine in the cells were not found to be significantly different in the presence of PGE2.

Animals↗