[Hyperprolactinemia effects on the female mice uterus during proestrous].

Purpose: To evaluate the effect of hyperprolactinemia induced by metoclopramide on the endometrium and myometrium of female mice in the proestrus phase.

Methods: 24 female mice were randomly divided in two groups: CtrG/control and ExpG/treated with metoclopramide (6.7 mg/g daily). After 50 days, the animals were sacrificed in the proestrus phase, and the blood was collected to determine the levels of estradiol, progesterone and prolactin. The uterine horns were removed, fixed in 10% formaldehyde and processed before being included in paraffin. Slices of 4 microm were stained by hematoxylin and eosin (H/E). In the morphological analysis, a Carl Zeiss light microscope, with objectives varying from 4 to 400 X was used for each histological slice characterization. In the morphometrical analysis, the superficial epithelium, the lamina propria and the myometrium thickness were evaluated, with the help of an image analyzer (AxionVision - Carl Zeiss) attached to the light microscope (Carl Zeiss). The statistical analysis was done by ANOVA, followed by the Wilcoxon test. P-value was considered as significant, when <0.05.

Results: Our findings have shown an increase in the seric levels of prolactin (295.6+/-38.0 ng/mL) and significant decrease in the progesterone levels (11.3+/-0.9 ng/mL) in the ExpG, as compared to the CtrG (45.5+/-5.2 ng/mL and 18.2+/-1.6 ng/mL, respectively; p<0.001). Concerning the seric level of estradiol, significant differences between the groups were not obtained (ExpG=119.1+/-12.3 pg/mL and CtrG=122.7+/-8.4 pg/mL; p=0.418). The morphological study has shown that the uterus from the ExpG presented the endometrium with more developed superficial epithelium and lamina propria, as compared to the CtrG, the same happening with the myometrium. The thickness morphometrical values of the luminal epithelium (8.0+/-1.1 microm) and endometrium (116.2+/-21.1x10(2) microm) from the CtrG were lower than the ones from the ExpG (10.2+/-0.8 microm and 163.2+/-23.3x10(2) microm, respectively) with p<0.05. Nevertheless, data obtained in the myometrium have not shown significant differences between the groups (CtrG=152.2+/-25.2x10(2) microm and ExpG=140.8+/-18.0x10(2) microm).

Conclusions: Data have shown that hyperprolactinemia induced by metoclopramide determines endometrial proliferation and interferes with the ovarian function, mainly in the progesterone production.