No abstract

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.

No abstract

Nitric oxide (NO) production may be an important causal factor in hypertensive disorders during pregnancy. The plasma concentrations of NO₂^––+NO₃^––, stable metabolites of NO, were measured in 70 nonpregnant women, 323 normotensive pregnant women, 23 pregnant patients with preeclampsia, and 7 pregnant patients with essential hypertension. The normotensive women had higher plasma concentrations (30.0 ± 0.6 µmol/l) than nonpregnant women (18.3 ± 1.0 µmol/l; p < 0.0001). The plasma concentrations in the patients with preeclampsia (45.6 ± 2.3 µmol/l) were higher than in the normotensive women (30.3 ± 1.0 µmol/l; p < 0.0001) and were correlated with the systolic blood pressure (r = 0.442; p < 0.05). However, pregnant patients with underlying essential hypertension had significantly lower plasma concentrations (19.1 ± 3.0 µmol/l; p < 0.005). These findings suggest that NO contributes to maternal vasodilation, the maintenance of uterine quiescence, and the pathogenesis and clinical features of hypertensive disorders during pregnancy.

Oxytocin (OT) is widely used to induce labor in the clinical setting. However, its physiological role in normal human parturition remains unclear. We demonstrated the enhanced expression of OT receptor (OTR) mRNA in chorio-decidual tissue, using the polymerase chain reaction after the reverse transcriptase reaction (RT-PCR)

We describe here the binding and functional properties of a cloned human oxytocin receptor (OTR). We established a transient OTR expression system on COS-1 cells, which do not express vasopressin receptors. With the transfected cells and [3H]oxytocin, the dissociation constant (Kd) of OTR to oxytocin was 6.0 +/- 1.1 nmol/l; the binding properties of several oxytocin-related peptides were also examined. The functional properties of OTR were determined by an electrophysiological method, using a Xenopus laevis oocyte injected with in vitro transcribed OTR mRNA. These two methods showed that [Phe2,Orn8]vasotocin, a vasopressin agonist, was an OTR antagonist. A combination of these methods using cloned OTR cDNA is a novel and effective method for the investigation of oxytocin-related ligands.

No abstract

These findings indicate that nitric oxide concentration in the seminal plasma of infertile males is elevated and that nitric oxide is an inhibitor of sperm motion.