HORMONES AND NOCTURNAL PENILE TUMESCENCE IN HEALTHY AGING MEN

There is no information on the relationship between endogenous pituita ry and gonadal hormones and nocturnal penile tumescence (NPT) in healt hy aging men. Sixty-seven married volunteers ages 45-74 years were stu died in the sleep laboratory for 4 nights with the last night devoted to sequential blood sampling every 20 min. Bioavailable testosterone ( Bt) correlated significantly with several NPT measures while total tes tosterone, estradiol, LH, and prolactin were mostly unrelated to NPT. All bT-NPT correlations lost their significance after adjustment by mu ltiple regression for the effect of age on both bT and NPT variables i n the total subject sample. Analysis of bT-NPT relations by age groups revealed a significant association between bT and duration NPT in men ages 55 to 64 years, but no statistical relations in younger and olde r age groups. Changes in the central threshold of activation of NPT as age progresses may explain the age-dependent effect of bT in sleep er ections.