Reverse transcription-polymerase chain reaction screening for FSH receptor mRNA in rat uterine tissue

Luteinizing hormone/chorionic gonadotropin hormone receptors have been localized to extraovarian sites in the mammalian female, including uterus. In the ovary, LH receptor expression is regulated in part by the binding of FSH to its own receptor. The objective of this study was to investigate the possible uterine expression of FSH receptor mRNA in uterine tissue. Rat ovary, uterus, liver, kidney, and hypothalamus were screened for the expression of FSH receptor mRNA by means of a reverse transcription - polymerase chain reaction (RT-PCR) amplification assay. Immature rats were primed with PMSG to stimulate follicular growth and development, followed 52 hours later by an injection of hCG to induce ovulation. Rats were then sacrificed at selected times (i.e. 2, 3, 6, 10, 13 days) following PMSG treatment. Total cellular RNA was isolated from tissues and used as template for reverse transcription using avian myeloblastosis virus (AMV) reverse transcriptase and an oligonucleotide primer complementary to the rat FSH receptor cDNA sequence. The cDNA product of the RT reaction was then used as template for PGR. The primers used in the PGR were designed to specifically amplify a 761 base pair region of the FSH receptor cDNA sequence. Upon electrophoretic separation of the RT-PCR products, the 761 bp product, and thus expression of FSH receptor mRNA, was evident in ovary from each of the time points tested. The 761 bp product was not present, however, in any of the other tissue types, including human endometrium. These results suggest that FSH binding to receptor in the uterus is not involved in regulating the uterine expression of LH/CG receptors. As such, further studies are needed to determine the factors and mechanisms regulating ectopic LH/CQ receptor expression.