Combined Oral Arginine and Monosodium Glutamate Exposure Induces Adverse Response on the Prostate Function and Testis Histology of Rats

Aims: This study investigated the effect of exposure to arginine (ARG) and glutamate (GLU), or its variant, monosodium glutamate (MSG) on the prostate function and testis histology of rats.
Study Design: Exposure to either ARG, GLU, monosodium glutamate (MSG), ARG plus GLU or ARG plus MSG was per oral for 4 consecutive weeks. On the last day of the experiment, rats were food-deprived for 15 h before collecting their blood and testis samples.
Place and Duration of Study: Department of Biochemistry and Department of Veterinary Pathology, University of Nigeria Nsukka, Nigeria, between June 2005 and June 2006.
Methodology: Total and prostatic acid phosphatase activities in serum were determined by the method of Walter and Schutt. Testis sections were stained and mounted using haematoxylin and eosin (H&E), for histology.
Results: On comparison with control, the results showed that ARG, GLU, or arginine together with monosodium glutamate (ARG+MSG) induced a significant (p<0.05 and p<0.01) elevation whereas, ARG+GLU caused a reduction (p<0.05 and p<0.01), in serum total acid phosphatase (TAP) and prostatic acid phosphatase (PAP) activities. MSG-induced reduction in TAP activity (20.76 ± 0.18 I.U/L), however, was not statistically significant (p>0.05 and p>0.01). Histological examination of the testis sections revealed varying degree of degeneration characterized by necrosis in ARG+GLU and ARG+MSG groups relative to control and ARG, GLU or MSG groups.
Conclusion: Results may indicate variable treatment related adverse effect on the prostate function and the testis histology of the rats. The possible effect, however, appeared higher following concomitant exposure to ARG and MSG. Thus, caution should be exercised in the simultaneous ingestion of arginine and monosodium glutamate in animals. Further work however, is required to address some shortcomings (including small sample size) of this study to validate reliability.