The present study, to our knowledge, is the first to demonstrate presence o
f progesterone receptor (PR) transcript in human spermatozoa. The study sho
ws the presence of low copy number PR mRNA in mature human spermatozoa. The
PR transcript in spermatozoa was detected by reverse transcriptase-polymer
ase chain reaction using primers specific for the hormone binding domain an
d the DNA binding domain of the conventional uterine PR. Further, the cDNA
sequence of the partial PR transcript from spermatozoa was found to be iden
tical to the region spanning nucleotides 2694 to 3230 of the conventional P
R full-length cDNA sequence. This study also indirectly suggests that the P
R protein indeed is an intrinsic sperm protein and is not acquired through
proteinaceous secretions of accessory reproductive organs.