Effect of caval-portal shunt on ovarian tissue in rats: I. Histological observation.

Forty-three female Sprague Dawley rats, divided into five groups, had undergone removal of the right ovary and one-half of the left ovary, the left ovary, and one-half of the left ovary, respectively. Group 4 rats were not subjected to ovariectomy. Group 5 animals were not subjected to CPS but underwent left ovarian hemiresection. The ovarian volume of the hemiresected ovaries increased to 393.00 ± 4.83 mm3 and 126.00 ± 44.3 mm3 from 18.40 ± 0.54 mm3 and 18.40 ± 0.59 mm in groups 1 and 3, respectively, at the end of three postoperative months. The nonresected ovaries enlarged to 339.98 ± 5.09 mm3 and 226.3 ± 46.2 mm3 from 36.79 ± 1.09 mm3 in groups 2 and 3, respectively. When no ovaries were resected, the CPS animals in group 4 showed an increment of ovarian volume of 1.75–2.2 times as much as the preoperative ones. In the animals that had undergone simple hemiovariectomy (group 5), the contralateral ovaries showed a significant increase in volume (40.2 ± 8.3 mm3 to 243.1 ± 114.8 mm3) at 3 months. The hemiresected ovarian volume increased from 27.1 ± 5.5 mm3 to 44.1 ± 11.8 mm3. The histological sections of ovaries in group 1 showed early formation of theca-luteoma 3 months postoperatively, and there were demonstrable corpora atretica 6 months postoperatively. In the group 2 ovarian sections, there were multiple follicular cysts, and these cysts were lined by clusters of granulosa cells. There were nondisintegrated ova ejected from the cumulus oophorus in the ovarian sections from group 2 3 and 6 months postoperatively. In the group 3 ovaries, there were abundant theca-luteal cells in the sections. Prominent granulosa-theca cell activity was present in the ovaries subjected to CPS. A similar observation was made in group 4, where more ovarian mass was left in situ. Group 5 animals not subjected to CPS showed compensatory hyperplasia in the nonresected ovaries, and the hemiresected ovaries showed a slight enlargement. No typical granulosatheca cell tumors were formed in any of the groups of rats, indicating that gonadotrophin-estrogen imbalance could not be achieved as a result of the large quantity of the ovary remaining in situ. © 1993 Wiley-Liss Inc.