Understanding chemistry of spermatozoa using NMR

Tata Institute of Fundamental Research, Mumbai-400 005, India Fax : 091-22-215-2110/2181 In recent years, NMR has found wide applications, on one end to study the structure of molecules and on the other, to study intact body organs such as brain or heart. In between these two extremes is another fascinating branch of science, namely, the study of chemistry of intact cellular systems. While dedicated instruments for this type of work are not available, it is possible to use high field high resolution NMR spectrometers meant for molecular studies (e.g. a 300-500 MHz instrument) to obtain chemical and biological information on living cells. We have studied the chemistry of one of the important cellu­lar systems, spermatozoa, using NMR. Spermatozoa play a key role in reproductive biology. Using techniques such as HSQC, it has been possible to obtain information on the 1H and 13C NMR features of such cells. We have been able to detect a number of molecules in these sperm cells, which had evaded detection by conventional chemical tools. It has been possible to follow chemical pathways and kinetics of metabolism using conventional 13C NMR. 31P NMR provides valuable informa­tion on the energetics and pH profiles. Some of these studies have helped us to know how such cells can be activated or deactivated. For example, arginine deficiency is known to cause diseases such as oligospermia and asthenospermia. NMR experiments have established that the glycolysis and fructolysis of spermatozoa is activated by arginine. Arginine also in­creases synthesis of ATP, which is essential for sperm motility. The chemical information thus obtained has major biological implication for storage, activation and control of spermatozoa