Duration of the cycle of the seminiferous epithelium, estimated by the 5-bromodeoxyuridine technique, in laboratory and feral rats

• Published in: Journal of reproduction & fertility Vol. 100; no. 1; pp. 299 - 306
• Main Authors: Rosiepen, G, Weinbauer, G F, Schlatt, S, Behre, H M, Nieschlag, E
• Format: Journal Article
• Language: English
• Published: England Society for Reproduction and Fertility 01.01.1994
• Subjects: Animals; Animals, Wild - physiology; Bromodeoxyuridine - pharmacology; Cell Count; Flow Cytometry; Follicle Stimulating Hormone - blood; Male; Rats; Rats, Sprague-Dawley; Seminiferous Epithelium - physiology; Spermatogenesis - drug effects; Spermatogenesis - physiology; Spermatozoa - physiology; Testis - cytology; Testosterone - blood
• ISSN: 1470-1626; 0022-4251; 1741-7899
• DOI: 10.1530/jrf.0.1000299

The stability of the duration of the cycle of the seminiferous epithelium was determined by investigating incorporation of 5-bromodeoxyuridine into S-phase germ cells of normal and hemicastrated standard laboratory rats (Sprague–Dawley) and feral Brown/Norway rats ( Rattus norvegicus ). Feral rats were trapped on farms in the surroundings of Münster. The duration of the cycle of the seminiferous epithelium, determined at intervals of 12 days (3 h versus 12 days 3 h after 5-bromodeoxyuridine injection), was remarkably constant and similar in intact laboratory rats (12.49 ± 0.05 days, n = 13, mean ± sem ) and feral rats (12.44 ± 0.06 days, n = 8). In hemicastrated laboratory and feral rats the duration of the cycle was similar to that in intact animals, indicating that hemicastration did not influence the kinetics of the seminiferous epithelium cycle. However, the coefficients of variation of the estimated duration of the cycle of the seminiferous epithelium were at least three times lower in hemicastrated rats (one testis from the same animal serving as reference point) compared with that of intact rats (the reference point based on the average staining frequency at 3 h). Overall, no significant differences between laboratory and feral rats could be observed with regard to testis weight and serum concentrations of FSH and testosterone. The number of cells per testis, determined by flow cytometry, was similar in laboratory and feral rats, except for a slight but significant difference in the haploid:tetraploid cell ratio (6.3 ± 0.2 versus 7.5 ± 0.3, P < 0.05). It is concluded that the duration of the cycle of the seminiferous epithelium is identical in feral Brown/Norway rats and their descendent laboratory rat strain, Sprague–Dawley rats. Hemicastration (each animal being its own reference point) profoundly increased the precision of the determination of duration of the cycle of the seminiferous epithelium, at least for the duration of one cycle.