The Journal of Reproduction and Development Supplement

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[Objectives] The present study was undertaken to determine the effect of active immunization against inhibin on hormonal profile and sperm production in bucks. [Methods] The bucks were actively immunized against inhibin (immunized group; n = 6) or Freund adjuvant (control group; n = 5) four times at intervals of 5 weeks. Blood samples were collected twice weekly and two successive ejaculates of semen were collected once a week by artificial vagina. Plasma levels of FSH, LH and testosterone were measured by RIA. The sperm motility characteristics were measured by computer-assisted sperm analysis. [Results] The results showed that all inhibin-immunized bucks generated antibodies against inhibin. In addition, plasma levels of FSH increased significantly from 5 to 9 weeks after immunization in inhibin-immunized bucks compared with controls. Furthermore, sperm concentrations increased significantly in inhibin immunized group from 8 to 11 weeks after immunization. However, plasma levels of LH and testosterone, semen volume, percentage of motile spermatozoa and motility parameters (straight line velocity; curvilinear velocity and linearity index) were similar in both groups. In conclusion, active immunization against inhibin increased FSH secretions and enhanced sperm production in bucks. Therefore, inhibin immunization could be used to improve fertility in bucks. This work was supported in part by a Grant-in-Aid for Scientific Research (The 21st Century Center of Excellence Program, E-1) from the Ministry of Education, Culture, Sports, Science and Technology of Japan and a Grant-in-Aid for Scientific Research (No. 03338) from the Japan Society for the Promotion of Science

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[Objectives] Cytoskeletal proteins maintain the cellular structures and functions. Generally in testis, actin microfilaments contribute for tubular contractility and vimentin, one of the intermediate filaments, supports Sertoli cell nucleus. It is yet to be understood whether or not postnatal alpha-smooth muscle actin (αSMA) and vimentin distribution is related to developmental changes in bovine testis, we aimed to demonstrate their localization pattern during postnatal development. [Methods] Testes sections of Holstein bulls from 0-month to 7-year (n=50) were prepared and immunohistochemical technique was applied using monoclonal αSMA and polyclonal vimentin antibodies. [Results] αSMA in peritubular, sub epithelial and stromal cells of seminiferous, straight and rete tubules appeared at around 4-month of age. After that, seminiferous peritubular αSMA soon attained the mature pattern whereas mediastinal αSMA amount increased with advancing age. Vimentin was localized in Sertoli cell perinucleus, which is weak at birth and increases moderately till 4-month. From around 5-month, increase in intensity and changes in its localization pattern were observed with characteristic vimentin extensions from the basal membrane to transforming Sertoli cell nucleus. These extensions gradually get shorter as the Sertoli cell nucleus is positioned basally and perinuclear vimentin appears stable without extension in mature Sertoli cells. [Conclusion] The age of peritubular and mediastinal αSMA appearance coincides with onset of spermatogenesis and vimentin may play the key role to maintain the proper position of Sertoli cell nucleus during postnatal development in bovine.

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