Vasectomy in the Rat--Effects on Mineral Metabolism, with Emphasis on Renal Tissue Minerals and Occurrence of Urinary Stones

Abstract

An increased stone frequency and hypotestosteronemia after vasectomy were reported and suggest development of some disturbance of homeostasis of minerals and hormones. The objective of the present study in the rat was to assess the effects of vasectomy (n = 14) and vasovasostomy (n = 12) on gonadal state, intestinal absorption of minerals and mineral concentrations in serum, urine and 3 renal tissue regions. Sham-operated animals (n = 12) served as controls. Seven months after surgery the combined results show that vasectomy induced a significant decrease in gonadal weight, but not in serum and urinary testosterone; serum magnesium was decreased (p = 0.014 versus controls) and phosphaturia was increased (p = 0.025), whereas serum calcium, parathyroid hormone and urinary cyclic AMP were unchanged. Also, after vasectomy there was a significant accumulation of phosphorus, calcium and magnesium in renal papillae and additionally of phosphorus in the renal cortical and medullary region; oxalate was unchanged. Renal stones containing calcium phosphate were found in 2 vasectomized rats, but in none of the vasovasostomized ones. In contrast, in vasovasostomized rats, mineral accumulation in renal tissues was abolished, and the associated concentration of serum free testosterone was 3 times higher (p = 0.018) than in control rats. It was concluded that vasectomy in the rat 1) may not be neutral to gonadal function in terms of gonadal weight; 2) disturbs the homeostasis of magnesium, calcium and phosphorus at the level of the kidney; and 3) induces mild hypomagnesemia and marked hyperphosphaturia in the presence of normal parathyroid gland function. It is suggested that these sequelae of vasectomy and vasovasostomy may be traced back to a disturbance of autonomous nerve tone.