EXPRESSION OF EXTRACELLULAR-SUPEROXIDE DISMUTASE IN THE HUMAN MALE REPRODUCTIVE-TRACT, DETECTED USING ANTISERA RAISED AGAINST A RECOMBINANTPROTEIN

Mammalian spermatozoa are particularly susceptible to the deleterious effects of reactive oxygen species and lipid peroxidation, which ultim ately lead to impaired fertility. A number of enzymes are present in t he male reproductive tract which may play a role in preventing oxidati ve damage; in particular, the epididymis is the site of synthesis and secretion of large amounts of extracellular superoxide dismutase (eSOD ). In order to study the distribution of eSOD in the male reproductive tract, and distinguish it from other related superoxide dismutase iso enzymes (e.g. cytosolic SOD), polyclonal antisera have been raised aga inst a recombinant human eSOD fusion protein, expressed in bacterial c ells. This protein was expressed from a synthetic gene fragment, using preferred Escherichia coli codons, designed to overcome the problems associated with the high guanine+cytosine content of the natural human eSOD transcript. Using this antiserum, eSOD can be readily detected i n a range of human reproductive tissues as well as in human seminal pl asma. However, the presence of similar levels of eSOD in the seminal p lasma of vasectomized men (probably of prostatic origin) precludes its use as a simple diagnostic indicator of eSOD activity levels in the e pididymis.