Effects of metoclopramide-induced hyperprolactinemia on the prolactin receptor of murine endometrium.

OBJECTIVE: To evaluate the effects of metoclopramide-induced hyperprolactinemia on the prolactin receptor of murine endometrium.

DESIGN: Experimental study using the RNA extraction to detect tissue prolactin receptor isoforms by reverse-transcriptase polymerase chain reaction (RT-PCR).

SETTING: University-based laboratory.

ANIMAL(S): Seventy-two female swiss albino mice (Mus musculus), approximately 100 days old, were divided into six 12-animal groups: (GI) nonoophorectomized mice given vehicle; (GII) nonoophorectomized mice treated with metoclopramide; (GIII) oophorectomized mice treated with metoclopramide; (GIV) oophorectomized mice treated with metoclopramide and 17beta-estradiol; (GV) oophorectomized mice treated with metoclopramide and micronized progesterone; (GVI) oophorectomized mice treated with metoclopramide and a solution of 17beta-estradiol and micronized progesterone.

INTERVENTION(S): Drugs were administered for 50 days. Following euthanasia, the middle portions of the uterine horns were removed, sectioned, and immediately frozen for RT-PCR procedures. Blood was collected for the dosage of prolactin and serum estrogen and progesterone using radioimmune assay.

MAIN OUTCOME MEASURE(S): Identification of uterine prolactin receptor isoforms.

RESULT(S): The PRL receptor and its isoform L were identified only in GI (control group) and GII (metoclopramide), the two groups with nonoophorectomized animals. The amount of PRL receptor mRNA and that of its isoform L from GII were the largest. No other isoforms of the prolactin receptor were identified in any of the groups.

CONCLUSION(S): Our results suggest that replacement of estrogen and progestin may not increase the mRNA of endometrial PRL receptor in metoclopromide-induced hyperprolactinemia in rats after castration.