Serum prolactin, FSH, LH and testosterone before and after vasectomy in normal men.

Abstract

In this study serum prolactin, follicle stimulating hormone (FSH), luteinizing hormone (LH), and testosterone levels were determined before and after vasectomy in 22 normal men. Vasectomy was performed through a bilateral 1.5 cm incision under local anesthesia in the conventional manner. The 22 men ranged in age from 23-45 years. Routine laboratory kits and methods were used for the estimation of the serum levels of prolactin and testosterone. Serum was collected at 8:30-9:30 a.m. 4 weeks prior to the vasectomy and 1 week, 3 months, and 6 months afterwards. The samples were kept frozen at -20 degrees Centigrade until analyzed. For verification of the results, a semen analysis was performed 3 months after the operation. There were no complications during the 6 month follow-up period. All the patients were azoospermic 3 months after vasectomy. The only significant change was elevated LH in serum already after 1 week, continuing to rise for the whole 6 months. The increase in FSH was insignificant. Serum testosterone and prolactin remained unchanged. The sample for 4 of the men happened to be taken on the operating table immediately prior to the operation, and 3 of the men showed a value more than twice as high as the control taken 4 weeks earlier. The study results are in agreement with the majority of earlier reports. During the 6 month follow-up period there were no significant changes in the serum FSH or testosterone values. Testosterone had a tendency to decrease 1 week after the vasectomy, but the change was insignificant and had returned to the baseline within 6 months after the operation. None of the mean hormone levels exceeded the ranges for normal men. The physiologic significance of the hormone changes after vasectomy remained unclear. There is no correlation between the serum levels of FSH, LH, and sperm count on the 1 hand and serum prolactin levels on the other, in hyperprolactinemic or azoospermic men. The role of prolactin in male fertility is unclear, but its interaction with gonadotropins along the hypothalamus-pituitary-testis axis may be important for normal spermatogenesis.