The histomorphometry and the secretory activity of the uterine tubes and uterus of 38 puberal Wistar rats were studied. Rats were divided in four groups: (1) euthyroid in proestrus-estrus, (2) hyperthyroid in proestrus-estrus, (3) euthyroid in metestrus-diestrus and, (4) hyperthyroid in metestrus-diestrus. In other experiment, 24 prepuberal 12-day-old Wistar rats were divided in two groups: (1) hyperthyroid and (2) euthyroid. The uterus and the uterine tubes were collected for histomorphometry and histochemical analyses. The ampulla's epithelial height has risen under the thyroxine treatment in proestrus-estrus as well as in metestrus-diestrus, becoming similar to the isthmus. The hyperthyroidism increased the PAS positive and acid mucosubstances secretions of the infundibulum on the estrogenic phase coming up to the isthmus. The uterine wall in the estrogenic phase was thicker due to the thyroxine action on the endometrium and myometrium. The secretory activity and uterine collagen composition did not differ between treatments. In puberal rats, the hyperthyroidism increased the thickness of the myometrium and the uterine wall, but did not alter the uterine tubes. Hyperthyroidism on prepuberal rats induced significant changes only in the uterus. After sexual maturity, changes in the uterus and uterine tubes were observed with variable intensity and were dependent on the estrous cycle phase.
rat; uterine tube; uterus; hyperthyroidism
