3alpha-hydroxysteroid dehydrogenase messenger RNA transcription in the immature rat ovary in response to an ovulatory dose of gonadotropin.
The ovulatory process in mammals involves a substantial increase in the metabolism of steroids and eicosanoids in response to a surge in LH or to an injection of hCG into experimental animals. This study provides evidence that the ovulatory stimulus causes induction of the gene for 3alpha-hydroxysteroid dehydrogenase (3alpha-HSD), an enzyme that belongs to several oxidoreductase superfamilies that affect steroid and eicosanoid metabolism. Immature Wistar rats were primed with 10 IU eCG s.c., and 48 h later the 12-h ovulatory process was initiated by 10 IU hCG s.c. Ovarian RNA was extracted at 0, 2, 4, 8, 12, and 24 h after injecting the animals with hCG. The RNA extracts were used for reverse transcription-polymerase chain reaction (PCR) differential display to detect gene expression in the stimulated ovarian tissue. One of the PCR primer sets differentially amplified a cDNA fragment that is 52.3% homologous with a 3alpha-HSD gene in rat liver. Northern analyses revealed that maximum transcription was at 8 h after the animals had been treated with hCG. The Northerns also indicated that the 3alpha-HSD cDNA probe cross-hybridized with as many as six different bands of mRNA on the blots. In situ hybridization localized 3alpha-HSD mRNA in the granulosa and thecal layers of mature follicles and in newly formed corpora lutea at 24 h after the ovulatory stimulus. In conclusion, gene(s) for 3alpha-HSD are transcribed in ovarian follicles in response to an ovulatory dose of gonadotropin. A possible function of the oxidoreductase enzyme that is translated from the 3alpha-HSD mRNA may be to reduce the toxic aldehyde and ketone components of the steroids and eicosanoids that accumulate in the mammalian ovary at the time of ovulation.
Espey
L L
LL
Department of Biology, Trinity University, San Antonio, Texas 78212,USA. lespey@trinity.edu
Yoshioka
S
S
Ujioka
T
T
Fujii
S
S
Richards
J S
JS
D015096:3-Hydroxysteroid Dehydrogenases / Q000096:biosynthesis*; D045002:3-alpha-Hydroxysteroid Dehydrogenase (B-Specific); D000447:Aldehydes / Q000378:metabolism; D000527:Alprostadil / Q000096:biosynthesis; D000818:Animals; D015152:Blotting, Northern; D018076:DNA, Complementary / Q000096:biosynthesis; D015777:Eicosanoids / Q000378:metabolism; D005187:Fallopian Tubes / Q000378:metabolism; D005260:Female; D006062:Gonadotropins / Q000494:pharmacology*; D017403:In Situ Hybridization; D007659:Ketones / Q000378:metabolism; D010053:Ovary / Q000187:drug effects / Q000201:enzymology* / Q000254:growth & development; D010060:Ovulation / Q000187:drug effects*; D011448:Prostaglandin Antagonists / Q000494:pharmacology; D011453:Prostaglandins / Q000378:metabolism; D012333:RNA, Messenger / Q000096:biosynthesis*; D051381:Rats; D017208:Rats, Wistar
D000447:Aldehydes; D018076:DNA, Complementary; D015777:Eicosanoids; D006062:Gonadotropins; D007659:Ketones; D011448:Prostaglandin Antagonists; D011453:Prostaglandins; D012333:RNA, Messenger; D015096:3-Hydroxysteroid Dehydrogenases; D045002:3-alpha-Hydroxysteroid Dehydrogenase (B-Specific); D000527:Alprostadil