EFFECTS OF LONG-TERM ANTIEPILEPTIC THERAPY ON THE CATABOLISM OF TESTOSTERONE

The serum levels of testosterone, sex hormone binding globulin, and fr ee testosterone index were measured in 51 epileptic men (age 18-45) in order to assess the possible effects of antiepileptic drugs on sexual dysfunction. An analytical gas chromatography-mass spectrometry metho d was developed to assess the urinary excretion of testosterone, epite stosterone, androsterone, etiocholanolone, 11-OH androsterone and 11-O H etiocholanolone and to evaluate if the catabolism of testosterone ha d been increased. Twenty normal healthy males of similar age, 18-45 ye ars, served as control group. Patients receiving polytherapy (n=34) or monotherapy with carbamazepine (n=8) or phenytoin (n=9) showed higher levels of sex hormone binding globulin and testosterone, and lower le vels of free testosterone than did the controls (P<0.03). Urinary excr etion of the metabolites androsterone and 11-OK androsterone was signi ficantly reduced (P<0.02) in the polytherapy group, while the monother apy group showed only significant differences (P<0.02) in the eliminat ion of 11-OH androsterone. Our results suggest that an induction of th e hepatic synthesis of sex hormone binding globulin may be the mechani sm by which the antiepileptic drugs lower the levels of free testoster one in serum. However, the reduced excretion of androsterone and the n ormal levels of etiocholanolone show that the antiepileptic drugs do n ot produce an increase in the main catabolism pathway of testosterone.