Sex-dependent urolithiasis in the portacaval shunt rat. Part I

Stone formation was investigated in 162 male and female Sprague-Dawley rats (96 males and 66 females) following a portacaval shunt and in 58 sham-operated rats which served as controls (31 males and 27 females). 70.8% male and only 7.5% female shunted rats developed urolithiasis. All stones of sufficient size were analyzed. The majority of stones in shunt-operated rats were made of potassium hydrogen urate (23/41), 10 rats had struvite stones without urinary tract infection, the remaining 8 rats had composite stones. Analysis of all stone-bearing control animals revealed struvite stones (6/6). Postoperatively, the rats developed polyuria, elevated potassium and uric acid excretion (all sex dependent). Urinary pH levels did not change significantly. Organ changes (atrophy of the liver, the testes and ovaries, hypertrophy of the kidney and the adrenal glands) were significant and differed according to sex. The role of sex hormones and prostaglandins is discussed.