Influence of lipid solubility on the sperm immobilizing effect of beta-adrenoceptor blocking drugs.

1 Sperm immobilizing effects of five beta-adrenoceptor blockers were measured on six human semen samples with a trans-membrane migration method. 2 The concentrations which decreased sperm motility to 50% of control (ED50) were 0.8, 4.2, 6.2, 11.0 and 33.0 mM for propranolol, oxprenolol, metoprolol, acebutolol and sotalol respectively. 3 There was a linear correlation between the log values of ED50 and the log partition coefficients of these beta-adrenoceptor blockers. 4 Because the lipid solubility determines the sperm immobilizing potencies of beta-adrenoceptor blockers, we support the theory that beta-adrenoceptor blockers inhibit sperm motility by stabilizing the cellular membrane. 5 The clinical implication of this finding is that more lipid soluble drugs are likely to have more interference on sperm function, at least when they are used locally.