The influence of age on Leydig cell function in patients with varicocele

In a large group of patients with varicocele (n = 108, mean age: 30.9 years) Leydig cell function was investigated by determining the plasma levels of gonadotrophins under basal conditions and after GnRH stimulation, and by measuring the plasma levels of 17-OH-progesterone (17-OH-P), testosterone (T), dihydrotestosterone (DHT) and oestradiol (E2). There was a significant positive correlation between age and the peak plasma LH values after GnRH stimulation (n = 48, r = 41, P less than 0.01). Conversely, an inverse correlation was observed between age and the basal plasma levels of 17-OH-P (n = 56, r = 0.47, P less than 0.01) and T (n = 108, r = 0.27, P less than 0.01). In normals controls of the same age range (n = 46, mean age: 30 years) such correlations were absent. In patients with varicocele, the 17-OH-P/T ratio was increased significantly in peripheral plasma under basal conditions (P less than 0.01) and after hCG stimulation (P less than 0.05), and a similar increase was found in spermatic venous blood. This suggests that in varicocele patients there is some enzymatic impairment involving the last steps of T biosynthesis. In order to verify the influence of ologozoospermia on plasma steroid levels we divided the patients into 2 groups according to sperm count (more than or less than 10 X 10(6)/ml). Three analyses of variance were then carried out between these 2 groups of patients: 1) analysis of peripheral plasma T levels; 2) analysis of peripheral plasma levels of 17-OH-P and 3) spermatic vein levels of these 2 steroids. However, none of these analyses revealed any significant difference between the 2 groups of patients. When we re-grouped the patients according to age (15-30 and 30-45 years) the same analyses of variance revealed significant differences. These results therefore suggest that the duration of idiopathic varicocele per se influences Leydig cell activity.