Visualization of reverse transcribed (RT) mRNA from human breast tissue that was PCR amplified with primers specific for progesterone metabolizing enzyme genes. (a) The PCR products were initially identified by separation on a 1.5% agarose gel. The products and number of cycles are as follows: Lane 2, 18S rRNA (12 cycles), Lane 3, 5αR1 (26 cycles), Lane 4, 5αR2 (33 cycles), Lane 5, 20αHSO (27 cycles), Lane 6, 3αHSO2 (27 cycles), and Lane 7, 3αHSO3 (27 cycles). (b) Restriction of the HSOs with PvuII and BamHI resulted in different fragments for 20α-HSO (lane 2; 423 bp, 142 bp), for 3α-HSO2 (lane 3; 423 bp and 167 bp) and for 3α-HSO3 (lane 4; 567 bp) when separated on a 9% polyacrylamide gel. The 26 bp fragments for 20α-HSO and 3α-HSO3 are not shown on the gel image.