Fig. 1.
In vitro effects of lead, silver, tin, mercury, indium and bismuth on creatine kinase activity obtained from human sperm. Samples (10 μg ml-1 creatine kinase equal with 1 unit activity) were incubated with different metal concentrations (5-100 μg ml-1) for 10 min at 25oC. Results are expressed as percentage of the corresponding control activities (unit per liter). Data have represented as the mean ± S.D. of triplicate determinations. *P<0.01 compared with control (in absence of heavy metals).