The efficacy of fertility-sparing treatment with a high-dose of MPA for EC and AH was proven by this prospective trial. Even in responders, however, close follow-up is required because of the substantial rate of recurrence.
Around the onset of labor, uterine sensitivity to oxytocin (OT) increases tremendously. Although this is considered to reflect OT receptor (OTR) augmentation in myometrium, neither spatial expression of OTR nor the level of the receptor message during the course of pregnancy have been investigated at the molecular level. We examined the localization and expression of the OTR in human myometrium by means of in situ hybridization, immunohistochemistry, and Northern and Western blotting. In the term pregnant myometrium, OTR expressing smooth muscle cells are observed diffusely and heterogeneously. Some of the smooth muscle cells were expressed high levels of the receptor at the messenger RNA and protein level, and they were surrounded with cells weakly positive for the OTR or negative. The level of OTR transcripts increased according to the course of pregnancy. The receptor messenger RNA level reached over 300-fold at parturition compared with the nonpregnant myometrium. In the myometrium at 32 weeks of gestation and not in labor, a relatively large amount (about 100-fold) of the receptor message was expressed. In the nonpregnant myometrium, significant amount of the receptor protein was revealed by Western blotting. We also found that the receptor protein was augmented at term and after the onset of labor. These findings indicated that the expression of OTR changes dynamically at the transcription and protein level during pregnancy and that its expression is heterogeneous in the term myometrium.
We have recently provided evidence for the desensitization of oxytocin receptors in human myometrial cells. In the present study, we have investigated the possible mechanisms by which oxytocin (OT) might regulate OT receptor density. The steady state level of OT binding in cultured myometrial cells was 220 x 10(3) binding sites/ cell, but this was time-dependently reduced to 27 x 10(3) sites/cell by exposure to OT for up to 20 h. Similarly, OT exposure decreased the binding of OT to cell membranes. In contrast, Western blotting data showed that the total amount of OT receptor protein was not affected by OT treatment for up to 48 h. Flow cytometry experiments demonstrated that OT receptors are not internalized during prolonged exposure of the cells to OT. However, RNase protection assays and Northern analysis showed that OT receptor mRNA was reduced by OT treatment to reach a new low steady state level with a time course similar to that of the disappearance of cell surface OT binding sites. Possible mechanisms involved in mRNA down-regulation include transcriptional suppression and destabilization of mRNA by RNA binding proteins.
Prostaglandin D synthase (PGDS) activity was detected in human seminal plasma (0.05-1.83 nmol/min per milligram protein). The enzyme was purified from human seminal plasma by immunoaffinity chromatography and found to be 27 kDa in size and N-glycosylated, similar to PGDS in the cerebrospinal fluid. The N-terminal amino acid sequence of 16 residues of the seminal enzyme, APEAQVSVQPNFQQDK, was identical to that of the cerebrospinal fluid PGDS. Although PGDS activity and the content determined by the immunoassay each highly varied in the seminal plasma, the concentration was significantly (p < 0.001) lower in the oligozoospermic group (2.47 +/- 0.51 microg/ml) than in the normozoospermic group (9.75 +/- 1.49 microg/ml). Prostaglandin (PG) D2 was detected in the seminal plasma (5.00 +/- 0.65 ng/ml) with a positive correlation to the PGDS concentration (p < 0.05). PGD2 was converted to the J series of PGs in the seminal plasma with a half-life of 6.5 h. Northern blot analysis revealed that mRNA for PGDS was expressed in the testis, prostate, and epididymis. Through immunohistochemistry, PGDS was localized in Leydig cells of the testis and in epithelial cells of the prostate and ductus epididymidis.
Secretory leukocyte protease inhibitor (SLPI) is a potent inhibitor of human leukocyte elastase. SLPI transcripts in the cervical tissue were detected during the menstrual cycle by reverse transcription-polymerase chain reaction (RT-PCR). Western blot analysis revealed that the intensity of SLPI protein in cervical tissue in the ovulatory phase was stronger than in other phases. Immunohistochemistry using an anti-SLPI polyclonal antibody revealed positive staining in the epithelial cells of the endocervix. Western blot analysis also revealed that SLPI protein was present in the cervical mucus. Again the intensity of SLPI protein in the ovulatory phase was stronger than that in the follicular phase. The SLPI concentrations and SLPI/elastase ratios in the cervical mucus of women in the ovulatory phase were significantly higher than in the follicular and luteal phases. The SLPI and elastase concentrations in the cervical mucus were positively correlated. No significant difference was found in the SLPI serum concentrations of women during the menstrual cycle. These results suggest that production of SLPI from cervical epithelial cells during the ovulatory phase may be important for protection from the effects of elastase.
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