BIOCONVERSION OF 17-ALPHA-HYDROXYPROGESTERONE INTO 17-ALPHA,20-ALPHA-DIHYDROXY-4-PREGNEN-3-ONE AND 17-ALPHA,20-BETA-DIHYDROXY-4-PREGNEN-3-ONE BY FLOUNDER (PLATICHTHYS-FLESUS) SPERMATOZOA

Flounder (Platichthys flesus) spermatozoa were incubated with 17 alpha -hydroxyprogesterone at 20 degrees C for 18 hr. After extraction of th e steroids from the incubation medium, steroid metabolites were analyz ed by gas chromatography-mass spectrometry (GC-MS). Selected ion monit oring with 25 possible steroid metabolites as standards represented th at main metabolites were 17 alpha,20 alpha-dihydroxy-4-pregnen-3-one ( 17 alpha,20 alpha-P) and 17 alpha,20 beta-dihydroxy-4-pregnen-3-one (1 7 alpha,20 beta-P). In addition small amounts of androstenedione and 1 7 alpha-hydroxy-5 beta-pregnane-3,20-dione were detected. Major two me tabolites were further identified using full mass spectrograms to be 1 7 alpha,20 alpha-P and 17 alpha,20 beta-P, respectively. These results indicate that flounder sperm cells show both 20 alpha- and 20 beta-hy droxysteroid dehydrogenase activities.