Experimental normocalcaemic hyperparathyroidism induced by renal venous congestion.

Ligation of the inferior vena cava above the renal veins in male Sprague-Dawley rats produces a predominantly transient renal injury with vascular congestion, tubular degeneration and necrosis with calcification. This is accompanied by impaired renal function with temporary azotaemia, hyperkalaemia, phosphate retention but with a normal calcium level. The parathyroid glands on the second postoperative day show cellular hypertrophy and on the third and fourth days signs of rapid cell proliferation with numerous mitoses. Thereafter the glands remain enlarged.