Effect of aging on the expression of nitric oxide synthase I and the activity of nitric oxide synthase in the rat penis / 中华男科学杂志

ABSTRACT

<p><b>OBJECTIVES</b>To investigate the effect of aging on the expression of nitric oxide synthase I (NOS I) and the activity of nitric oxide synthase in the rat penis.</p><p><b>METHODS</b>Thirty male rats from three age groups(adult, old and senescent) were investigated 1. The expressions of NOS I protein and mRNA in the penis were detected by Western blot and RT-PCR, respectively. 2. NOS activity in the penis was detected with ultraviolet spectrophotometry.</p><p><b>RESULTS</b>In rats of the old and the senescent groups, the expression of NOS I protein decreased significantly as compared to that of the adult group. NOS I mRNA expression was well related to its protein expression. NOS activity had no statistical difference between the adult group and the old group, but it reduced significantly in the senescent group as compared to that of the adult group(P < 0.01).</p><p><b>CONCLUSIONS</b>It is maybe one of the main mechanisms of erectile dysfunction in the aging male that the aging causes the decreases of NOS I protein and mRNA expression and NOS activity.</p>