| Abstract: | This study was carried out to determine the annual fluctuations of the tail bleeding time in the rat. Bleeding time was determined by transection of the tail of pentobarbital-anesthetized rats. Over a 6-year period, monthly measurement of the tail bleeding time revealed highly reproducible circannual fluctuations. Bleeding times were shortened in the summer (414 ± 18 s in July), being almost half that observed during the winter span (886 ± 32 s in January). The difference between these two time points was highly significant (p > 0.001). This study reports for the first time circannual variations of the bleeding time in the rat. |
