The Varicocele: Elevated Serotonin and Infertility

Serotonin is known to be toxic to testicular function. In a series of canine studies serotonin was found to be elevated in both spermatic veins after creation of a varicocele by partial ligation of the left renal vein. A total of 42 consecutive infertile male patients with a palpable varicocele and a seminal stress pattern had peripheral and spermatic vein serotonin levels determined at the time of high spermatic vein ligation. Of these patients 27 (64 per cent) had spermatic vein serotonin levels equal to or greater than peripheral levels. These patients demonstrated significantly lower sperm motility, percentage of live sperm and elevated percentages of immature and tapered sperm forms compared to those patients with lower spermatic vein serotonin levels. The interrelationships among the varicocele, premature sloughing of immature sperm and serotonin are discussed.