Ultra high field NMR spectroscopic studies on human seminal fluid, seminal vesicle and prostatic secretions.

Ultra high field 1H-NMR spectroscopic methods have been used to analyse the composition of seminal fluid and its component secretions, prostatic and seminal vesicle fluids from normal human subjects and those with vasal aplasia and non-obstructive infertility. The 1H-NMR spectrum of whole seminal fluid is extremely complex and many resonances are extensively overlapped in single pulse spectra even when measured at 600 or 750 MHz 1H resonance frequency. A combination of 2-D 1H-NMR methods (including J-Resolved and various 1H homonuclear correlation and 1H-13C heteronuclear correlation techniques) were applied at 600 or 750 MHz in order to extensively assign the signals from the organic components of seminal fluid. Prostatic fluid (PF) gives a much less complex metabolite profile than whole seminal fluid and can be completely analysed using 500 MHz 1H-NMR spectroscopy. The 1H-NMR spectra of prostatic fluid are dominated by signals from citrate, spermine and myo-inositol, whereas the spectra of seminal vesicle fluid (SVF) show extensively overlapped signals from complex peptide mixtures together with strong signals for glycerophosphocholine (GPC) and lactate. Whole seminal fluid is a combination of the PF and SVF constituents together with further substances that appear after mixing due to the operation of PF enzymes on SVF, e.g. peptidase activity causes rapid cleavage of peptides to amino acids and GPC is hydrolysed to choline, glycerol and inorganic phosphate. It is also shown that vasal aplasia leads to highly characteristic abnormal metabolite profiles in seminal fluid that can be readily observed in single-pulse 500 and 600 MHz 1H-NMR spectra. Measurement of the molar citrate to choline, or spermine to choline ratios in seminal fluid both show differences of 2 orders of magnitude between vasal aplasia (greater for both ratios) and non-obstructed infertile patients. This work gives an indication of the potential of high field 1H-NMR spectroscopy in the investigation and assessment of the secretory functions of the male genital tract and the evaluation of the infertile male subject.