This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Jin, W. Articles by Taya, K. Search for Related Content PubMed PubMed Citation Articles by Jin, W. Articles by Taya, K.

Inhibin B Regulating Follicle-Stimulating Hormone Secretion During Testicular Recrudescence in the Male Golden Hamster

WANZHU JIN^*,

CHANDANA B. HERATH

MIDORI YOSHIDA

KOJI Y. ARAI

ERINA SAITA^*,

SHI ZHANQUAN^*,

LONGQUAN REN^*,

GEN WATANABE^*,

KAZUYOSHI TAYA^*,

From the ^* Department of Basic Veterinary Sciences, The United Graduate School of Veterinary Sciences, Gifu University, Gifu, Japan; the Laboratory of Veterinary Physiology and the Department of Tissue Physiology, Tokyo University of Agriculture and Technology, Tokyo, Japan; the Department of Pathology, Sasaki Institute, Tokyo, Japan; and the ^|| School of Biological and Molecular Science, Oxford Brookes University, Oxford, United Kingdom.

Correspondence to: Dr Kazuyoshi Taya, Laboratory of Veterinary Physiology, Tokyo University of Agriculture and Technology, 3-5-8 Sai-wai-cho, Fuchu, Tokyo 183-8509, Japan (e-mail: taya{at}cc.tuat.ac.jp).

In the present study, to clarify whether inhibin affects follicle-stimulating hormone (FSH) secretion in the recrudescence of the male golden hamster, we used a recently developed specific enzyme-linked immunosorbent assay (ELISA) in order to measure 2 forms of inhibin molecules: inhibin B and inhibin pro-C. In addition, we used the radioimmunoassay (RIA) to measure immunoreactive (ir-)inhibin, FSH, luteinizing hormone (LH), and testosterone. And finally, we used the proliferating cell nuclear antigen (PCNA) and computer-assisted sperm motion analysis (CASA) methods to ascertain how well spermatogenesis and sperm motility recover from the photoinhibition caused by exposure to a short-day (SD; 10-hour light: 14-hour dark) photoperiod. Animals were exposed to SD for 15 weeks, and then their testes were checked carefully and found to be completely regressed. Thereafter, those animals were transported to a long-day (LD; 14-hour light: 10-hour dark) photoperiod. Sampling was carried out at weeks 0 (exposed SD 15 weeks), 1, 2, 4, 6, 8, and 10. Plasma FSH rapidly increased and reached peak levels 2 weeks after transferral to the LD photoperiod and then declined to normal LD levels at week 6. Circulating ir-inhibin, inhibin B, and inhibin pro-C rose to normal LD levels by week 4. A highly significant inverse correlation was observed between plasma FSH and inhibin B but not between FSH and either ir-inhibin or inhibin pro-C. Plasma testosterone recovered to normal LD levels within 1 week. Sperm motility parameters were low until week 2 and recovered to normal LD levels from weeks 4 to 10. PCNA-labeled cells were confined to the spermatogenic cells of the seminiferous tubules, though Leydig and Sertoli cell nuclei were never stained for PCNA during the period studied. The number of pachytene spermatocytes and the diameter of seminiferous tubules increased in a time-dependent manner after transferral from SD to LD. In conclusion, these results suggest that 1) secretion of inhibin B may be stimulated by an early rise in FSH; 2) inhibin B suppresses FSH secretion from weeks 2 to 10, after transferral to the LD photoperiod; and 3) testes recrudescence is based on the increase in the number of sperm cells instead of the increase in the number of Sertoli and Leydig cells of the male golden hamster.

     Key words: Photoperiod, proliferating cell nuclear antigen, sperm motion