Biochemical Correlates of Asthenozoospermia: A Lesion at the Level of the Sperm Adenylyl Cyclase

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Abstract
Studies of the adenylyl cyclase in spermatozoa from 10 asthenozoospermic and 10 normal men revealed major differences with regard to the activation of the enzyme by various drugs and metal ions. While the response to acetate ions was normal, activation of the enzyme by forskolin and the GTP analogue [Gpp(NH)p] was uniformly impaired. In addition, in 4 of the patients the ratios of the Mn2+ - and Mg -dependent activities of the enzyme were significantly higher than normal, suggesting a delay in the transformation of the enzymes catalytic unit from the soluble to the membrane-bound form. No differences could be recorded in a variety of seminal plasma components including prostatic acid phosphatase, citric acid, zinc, putrescine, spermidine, spermine, fructose, prostaglandin E, and testosterone. Furthermore, the DNA fluorescence patterns of the spermatozoa measured by flow cytometry were within the range of control variations, suggesting that chromatin condensation, and thus nuclear maturation, proceeded normally. The study suggests that a lesion in the adenylyl cyclase system of the germ cells may explain at least some of the motility disturbances seen in infertile males.