ISSN:
0003-276X
Keywords:
Life and Medical Sciences
;
Cell & Developmental Biology
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Medicine
Notes:
The cycle of the seminiferous epithelium of the boar was divided into eight stages which are described. The relative frequencies of the stages were determined for ten Yorkshire and ten Lacombe boars approximately 11 months of age. The mean relative frequencies for stages 1 through 8 were 10.8, 14.4, 3.5, 11.6, 8.9, 20.3, 18.5 and 12.0%, respectively. Generally, there was a constancy of the relative frequencies of the stages between breeds, among boars within breeds and between testes within boars.The absolute duration of the cycle of the seminiferous epithelium and the duration of spermatozoan transit through the epididymis were determined by injecting a single dose of 19 mCi of thymidine-methyl-H3 into the marginal ear vein of each of four Yorkshire (15.2 months old) and four Lacombe boars (14.9 months old). Unilateral castrations were performed at 0.2, 11.5, 20.0, 24.0 and 25.0 days after the isotope injection. Two intact and two unilaterally castrated animals were ejaculated for eight and seven weeks, respectively, to determine the interval between the thymidine-H3 injection and the appearance of the isotope in the ejaculated semen. Autoradiographs were prepared from the testis tissues and the semen smears. The most mature germ cells that incorporated the thymidine-H3 were the late preleptotene primary spermatocytes. Twenty-five days after injection the label had progressed from late preleptotene primary spermatocytes to spermatozoa leaving the testes. Epididymal transit times for four boars (ejaculated daily) were 9, 10, 10 and 12 days. The duration of one cycle of the seminiferous epithelium based on 12 estimates was 8.6 ± 0.1 days. The durations of stages 1 through 8 were 0.9, 1.2, 0.3, 1.0, 0.8, 1.7, 1.6 and 1.0 days, respectively. The life span of primary spermatocytes was 12.3 days, of secondary spermatocytes 0.4 days, of spermatids with round nuclei 6.3 days, of spermatids with elongated nuclei 1.5 days, and of spermatozoa 6.2 days.
Additional Material:
1 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/ar.1091610204
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