Biomedical subjects

S Navrátil

Publications and source records attributed to S Navrátil.

9 recordsLinked to original sources

PubMed1979

[Effect of bilateral vasectomy on testosterone levels in the seminal and blood plasmas of boars].

In two sexually mature boars subjected to bilateral vasectomy the content of testosterone was followed in the semen and blood plasma prior to the operation and in the course of 26 days after the operation. In the third boar only the operation without actual vasectomy as the control was made to eliminate the possible effect of narcosis and of the surgical stress. Bilateral vasectomy induced an average decrease in the initial levels of testosterone in the semen plasma of the first and second animal by 63.24% and 47.67% respectively, and 47.17% and 56.46% respectively in the blood plasma. In the control boar no analogous post-operation drop of testosterone concentration in the semen plasma was observed, the content of testosterone in the blood plasma decreased over the followed period on an average only by 14.38%. The results imply that bilateral vasectomy in boars results, in the first followed month after the surgical procedure, in a decrease of semen and plasma testosterone, which proves that the operation under investigation affects testicular incretion.

Animals↗

PubMed1979

[Effect of chorionic gonadotropin administration on the concentration of testosterone in the blood of boars].

In intact boars, intravenous administration of 100 to 6000 I. U. chorionic gonadotropin elicited a pronounced rise in the plasma level of testosterone, depending on the time interval from the administration of chorionic gonadotropin and on the size of the administered dose. In the blood of castrated boars such an application of choronic gonadotropin did not influence the concentration of testosterone. It was inferred that the rise in the levels of blood testosterone in boars after administration of chorionic gonadotropin was specific for testicular incretion and indicated the endocrine reserve of the testes. There is a discussion concerning the importance of the functional testing of the incretion capacity of testes for differential diagnosis different forms o incretion hypogonadism.

Animals↗

PubMed1979

[The effect of chorionic gonadotropin administration on testosterone levels in the blood of boars with sexual function disorders].

Thirty-three boars with sexual dysfunctions and twenty-six boars clinically sound as to their reproductive capacity were evaluated for the testosterone levels in the blood plasma before i.v. administration of 500 i.u. of chorionic gonadotropin and two hours after the administration. A group of animals with reproduction disorders comprised boars with an impaired quality of ejaculate and low fertility ability (18 boars) and with sexual dysfunctions (15 boars). No statistically significant difference in the basal concentration of testosterone in the blood was found in the boars with the studied sexual dysfunctions, as compared with the boars with no sexual dysfunctions. Administration of chorionic gonadotropin increased significantly the plasma testosterone levels in both groups. If the effect of chorionic gonadotropin on the studied level of this hormone was compared in boars with sexual dysfunctions and in boars without any disorders, no significant differences were proved. It has been inferred from the above findings that there are no significant disorders of androgen supply and incretion reserve of the gonads in the boars with sexual dysfunctions.

Animals↗

PubMed1979

[The effect of LH releasing hormone on testosterone levels in the blood of boars with sexual dysfunctions].

The levels were assessed of testosterone in the blood plasma before and 90 minutes after i.v. application of 1 mg of synthetic LH-releasing hormone to 57 boars with disorders of sexual functions and to 43 boars without sexual dysfunctions. The group of animals with sexual disorders included boars with inferior ejaculate quality and low fertility (24 animals) and cases with disturbed sexual potency (33 boars). In animals with the studied changes of sexual functions, compared with boars without sexual dysfunctions, no statistically significant difference was found in the basal concentration of testosterone in the blood. LH-releasing hormone application increased significantly the testosterone levels in the group of boars without sexual disorders by 99.5% on an average and in the whole group of animals with changes in sexual functions approximately by only 65.8%. At the same time in the subgroup of inferior ejaculate quality and low fertility the post-application increase of testicular incretion reached 60.4% and in potency disorders 61.6% and was statistically insignificant in the latter. On the basis of these findings it was derived that in boars with reproduction deviations there existed a decreased incretion reserve of the system hypophysis - testicle and the involvement of this factor in the formation of the studied sexual disorders is assumed. The obtained results are discussed in view of the earlier findings about the incretion reserve of the testicles in boars with changes in sexual functions.

Animals↗

PubMed1978

[Elimination of testosterone and androstendione in the urine of boars in relation to the incretory function of the testes].

The elimination of testosterone and androstendion in the urine was tested in six sexually mature boars. The administration of chorionic gonadotropin to intact animals resulted in a marked, statistically significant, rise of the amounts of excreted testosterone and, in part of the cases, androstendion. The responses were individual. Bilateral orchidectomy caused a statistically highly significant decrease of the elimination of both steroids under study without pronounced adrenocortical compensation. The administration of the adrenocorticotropic hormone to castrated boars did not exert any significant influence on the excretion of the substances studied. The use of chorionic gonadotropin given to the castrated boars did not produce any significant changes in the elimination of hormones. It has been inferred that testosterone as well as androstendion in the urine of boars are almost exclusively of testicular origin and that the response of the values of both steroids to the administration of chorionic gonadotropin is specific after testicular incretion. The discussion concerns the importance of these findings for the evaluation of the incretion reserve of the testes and for the diagnosis of incretion hypogonadism in boars.

Adrenocorticotropic Hormone↗

PubMed1978

[Variation of the serum testosterone level in boars during 24 hours and during a period of several days].

Seven sexually mature boars were studied in two-hour intervals for 8 to 32 hours, as to the variation of testosterone levels in the blood plasma. Blood samples were obtained by means of a cannula inserted in the v. cava cranialis. The hormone level under study showed marked fluctuation. The coefficient of variation of testosterone concentration ranged from 12.7% to 35.2% in the individual animals and for the whole part of the study it was 33.0%. It appeared impossible to derive seriously any regular periodicity of testosterone concentration in boar blood in the 24-hour period from the analysis of the variation of the levels of the hormone in individual animals during the period under study. Further, the study revealed a marked fluctuation of testosterone levels in the blood plasma of twelve sexually mature boars in the course of several days' study. The coefficient of variation of testosterone concentration in individual animals ranged from 18.1% to 106.5%, reaching 77.0% for the whole part of study. The analysis of variance showed statistically significant differences of hormonal levels in individual boars in which the fluctuation of testosterone was studied in the 8- to 32-hour period as well as in several days' period. This proved the role of the animals' individuality in determining the concentration of testosterone in their blood. The discussion concerns the importance of these findings for the evaluation of the role of basal testosterone levels in the blood in classifying the incretion function of the gonads and in the diagnosis of incretion hypogonadism of boars.

Age Factors↗

PubMed1978

[Effect of bilateral orchidectomy on serum testosterone levels in boars].

Bilateral orchidectomy caused a marked decrease in the concentration of testosterone in the bood plasma of boars already in the early post-castration stage of three hours after the operation. In the period from 3 to 207 days after castration, the pre-operation levels of plasma testosterone decrease by 84.4%, on an average. Adreno-cortical compensation of the concentration of the hormone did not occur in the post-castration period. The conclusion is that the levels of testosterone in the blood of boars are mostly of testicular origin and can be considered as the main criterion of the incretion function of the testes. The discussion concerns the practical importance of the determination of testosterone levels in the blood of boars for clinical evaluation of the hormonal function of the testes and for diagnostics of incretion hypogonodism.

Animals↗

PubMed1978

[Serum testosterone levels and response to administration of chorionic gonadotropins in bovine hermaphrodites].

The concentration of testosterone in the blood and its response to administration of chorionic gonadotropin was examined in two bovine intersexes (testicular pseudo-hermaphroditism) and two control bulls without disorders in sexual differentiation. The levels of testosterone in the blood were markedly lower in both intersexes than in the control bulls. Both intersexes, unlike the control bulls, also showed a response of the blood testosterone level to the administration of chorionic gonadotropin. The conclusion is that in the given type of intersexuality the incretion function of the testes is mardedly deficient as to androgen production and functional hormonal reserve.

Animals↗

PubMed1976

[Concentration of testosterone in the blood of sexually immature boars after stimulation with chorionic gonadotropin].

Levels of testosterone concentration in blood increased significantly in sexually immature boars after application of chorionic gonadotropin. Existence of considerable function reserve and readines of the incretion component of gonads were proved in sexually immature boars. The paper discusses a possibility of utilizing this phenonmenon in diagnostics of disorders of the incretion testicular function in individuals of the animal species under study in their pre-puberal age.

Animals↗