Arginine Activates Glycolysis of Goat Epididymal Spermatozoa: An NMR Study

Abstract

The present study explores the mechanism underlying the action of L-arginine on the metabolic activity of spermatozoa. Goat epididymal spermatozoa were incubated with different concentrations of L-arginine to determine its effect on the utilization of glucose, fructose, and pyruvate. NMR techniques have been applied to elucidate the effect of L-arginine, L-lysine, and L-ornithine on the glycolysis of epididymal goat spermatozoa. Whereas 31P NMR has been used to estimate the change of pH in the presence of different concentrations of L-arginine, 13C NMR has been used to estimate the substrate consumption and lactate production. At optimal concentration of L-arginine, the forward metabolic rates have been found to increase by two to three times over control experiments. Arginine is not consumed in these reactions, but acts as an activator. Longitudinal relaxation time (T1) measurements indicate that the guanidino group of L-arginine plays an active role in binding to cells. The amino acid L-lysine is less effective, and L-ornithine is ineffective.

Identification of endogenous metabolites in human sperm cells using proton nuclear magnetic resonance (1H-NMR) spectroscopy and gas chromatography-mass spectrometry (GC-MS)

“…3). In goat a high content of free amino acids was found in the ejaculate and the epididymal fluid, where these molecules could serve as chelating agents, in particular for toxic metals, and/or as oxidizable substrates for spermatozoa (Patel et al, 1998(Patel et al, , 1999. Amino acids could also serve as endogenous substrates in human sperm cells, but further studies are needed to validate this assumption.…”

“…Metabolomic studies have been performed in sperm cells from different species, such as goat (Patel et al, 1998(Patel et al, , 1999, boar (Jones & Bubb, 2000;Marin et al, 2003), turbot (Dreanno et al, 2000) and rhesus macaque Lin et al, 2009). Rat testicular tissue (Griffin et al, 2000) and human seminal plasma have also been subjected to metabolomic analyses (Hamamah et al, 1993;Gupta et al, 2011aGupta et al, ,b, 2013.…”

Identification of Low-Molecular-Weight Compounds in Goat Epididymis Using Multinuclear Nuclear Magnetic Resonance

“…These molecules act as chelating agents (especially of toxic metals), serve as oxidizable substrates for spermatozoa, provide buffers with protective influence on sperm cells, and undergo further metabolic changes in semen under the influence of transaminases and deaminases. Our results indicating the presence of arginine in goat cauda EF are highly implicated in its effect, in particular, stimulation of mammalian sperm motility in vitro (27)(28)(29), and in its beneficial effect on the sperm count for oligospermic semen after massive oral doses (30,31).…”

Effect of L-arginine treatment on motility, hyperactivity, acrosome reaction of ejaculated ram spermatozoa

“…Administration of L-arginine to oligospermic and asthenospermic patients results in an improvement in both the sperm count and motility without any side effects (Scibona et al, 1994;Aydin et al;. L-arginine plays an important role in stimulating sperm motility in humans, rabbits, and goats under in vitro conditions (Aydin et al, 1995;Patel et al, 1998;Srivastava et al, 2006). It has been confirmed that L-arginine enhances the rate of glycolysis, resulting in higher rates of adenosine triphosphate and lactate generation in spermatozoa.…”

“…It has been confirmed that L-arginine enhances the rate of glycolysis, resulting in higher rates of adenosine triphosphate and lactate generation in spermatozoa. The influence of arginine in reversing impairment caused by glycolytic inhibitors (potential contraceptives) has also been studied (Patel et al, 1998(Patel et al, , 1999. NO promotes mouse sperm capacitation and acrosome reaction (Griveau et al, 1995).…”