Reversible plasma testosterone levels reduction after gentamicin administration and freund's adjuvant arthritis in rats.

The present study was undertaken in order to investigate the influence of gentamicin on plasma testosterone levels of healthy and with Freund's adjuvant arthritis rats. Gentamicin (40 mg/day for 4 days) induced significant decrease of testosterone levels in comparison with the control group (P<0.025).

Loss of cardioprotection induced by ischemic preconditioning after an initial ischemic period in isolated rat hearts.

Background: The beneficial effect of ischemic preconditioning (PC) has been extensively studied in normal hearts but its effects on diseased hearts remain largely unknown. The effect of PC in the already ischemic myocardium has not been previously studied, although ischemia in varying intervals, which is difficult to assess, is often encountered in clinical practice.

Objective: To investigate whether the cardioprotective effect of PC is preserved when it is applied after a period of ischemia of varying duration.