A Comparison of Human Semen from Healthy, Subfertile, and Post‐Vasectomy Donors by 31P NMR Spectroscopy

Abstract

Preliminary characterizations of the phosphorylated compounds present in human semen were obtained using a JEOL FX90-Q Multinuclear NMR with a variable temperature accessory. Semen samples of 2.0 ml containing 12.5% D20 in a 10.0 mm sample tube were maintained at approximately 28.5 degrees Celsius. The spectra were recorded with a 250 msec pulse delay 1 sec acquisition time 0.95 sec acquisition delay and over the range of -16 ppm to 11 ppm. 3 distinguishable peaks were identified as glycerylphosphorycholine (GPC) at 0.00 ppm (this point was used as an internal standard) inorganic phosphate (Pi) at -2.45 ppm to -2.00 ppm and phosphorycholine (PC) at -3.4 ppm in accord with Arrata et al. A temporal study showed that in the hour immediately following ejaculation the original ratio of PC to total phosphate (P) decreased by 60% while the original ratio of GPC to total P did not change by a significant amount. These data contrast with those of arrata et al. who reported that PC hydrolyzed to Pi within 30 minutes and that GPC was stable. Data reported below were collected after a minimum of 60 minutes postejaculation following relative stabilization of GPC content. Semen specimens were evaluated either within 5 hours of collection (fresh) or quickly frozen without cryoprotectant and stored at -76 degrees Celsius (frozen). Ratios of GPC to total P differed with sample type. The authors observed the following ratios for GPC to total P: (0.17 0.15 0.16 0.19 0.099 0.16 0.15) N=7 with a mean of 0.15 +or- 0.028 for fresh healthy semen (0.085 0.070 0.086) N=3 with a mean of 0.080 +or- 0.008 for frozen health semen (0.074 0.074) N=2 with a mean of 0.074 for fresh subfertile semen (fig. 2) (0.11 0.040 0.060 0.00 0.060 0.00) N=6 with a mean of 0.045 +or- 0.042 for frozen subfertile semen and a ratio of (0.00 0.00 0.00 0.00) N=4 with a mean of 0.00 for postvasectomy specimens. While the data are generally consistent with those of Arrata et al. the authors detect a difference between fresh and frozen samples. This discrepancy may reflect partial biological hydrolysis of GPC and PC to Pi. The simple reliable quantification of GPC is important for further investigation of its biological significance. The authors suggest that 31P NMR analyses of human semen will play a valuable role in understanding detection and treatment of male infertility. (full text)