Serum and salivary cortisol release and mood ratings were measured in response to the procedure of LHRH tests in 12 medical students professionally familiarized with venipunctures (familiarized subgroup) and in 5 non-medical students (unfamiliarized subgroup). There were significant differences in cortisol and mood ratings between both groups. Only the unfamiliarized subgroup showed significant increases of cortisol and higher values for tension and anxiety. Relations between cortisol, tension and anxiety confirm an effect of experimental stress on the secretion of cortisol during the procedure of LHRH tests. Novelty and subjective mood states appear to have predictive values with regard to stress-induced endocrine reactions.