VASECTOMY IN THE RAT - EFFECTS ON MINERAL METABOLISM, WITH EMPHASIS ON RENAL TISSUE MINERALS AND OCCURRENCE OF URINARY STONES

An increased stone frequency and hypotestosteronemia after vasectomy w ere reported and suggest development of some disturbance of homeostasi s 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 miner al concentrations in serum, urine and 3 renal tissue regions. Sham-ope rated animals (n = 12) served as controls. Seven months after surgery the combined results show that vasectomy induced a significant decreas e in gonadal weight, but not in serum and urinary testosterone; serum magnesium was decreased (p = 0.014 versus controls) and phosphaturia w as increased (p = 0.025), whereas serum calcium, parathyroid hormone a nd urinary cyclic AMP were unchanged. Also, after vasectomy there was a significant accumulation of phosphorus, calcium and magnesium in ren al papillae and additionally of phosphorus in the renal cortical and m edullary region; oxalate was unchanged. Renal stones containing calciu m phosphate were found in 2 vasectomized rats, but in none of the vaso vasostomized ones. In contrast, in vasovasostomized rats, mineral accu mulation in renal tissues was abolished, and the associated concentrat ion 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 t he homeostasis of magnesium, calcium and phosphorus at the level of th e kidney; and 3) induces mild hypomagnesemia and marked hyperphosphatu ria in the presence of normal parathyroid gland function. It is sugges ted that these sequelae of vasectomy and vasovasostomy may be traced b ack to a disturbance of autonomous nerve tone.