Development of cytochrome P-450 side chain cleavage mRNA levels in neonatal ovaries of normal and hypogonadal (hpg) mice.
Cytochrome P-450 side chain cleavage (P-450scc) is vital for biosynthesis of gonadal steroids. In this study changes in P-450scc mRNA levels and cholesterol side-chain cleavage (CSCC) enzyme activity have been measured during development in the ovary of the normal mouse and the hypogonadal (hpg) mouse which lacks circulating gonadotrophins. Levels of P-450scc mRNA were measured using a semi-quantitative reverse transcription-polymerase chain reaction technique for which part of the 5' sequence of a mouse P-450scc cDNA was sequenced. On the day of birth P-450scc mRNA was present at low levels in the mouse ovary. Thereafter there was no change in P-450scc mRNA levels for 5 days after which time levels increased significantly to reach a peak around day 10. Activity of CSCC showed a similar pattern of development although activity was not detectable on days 1 and 3. In the hpg mouse P-450scc mRNA levels were normal on day 1 but did not increase thereafter up to 15 days. These results show that there is gonadotrophin-independent expression of P-450scc mRNA in the mouse ovary at birth when only primordial follicles and stromal tissue are present. As the ovary develops after 5 days changes in P-450scc mRNA levels become gonadotrophin-dependent and coincide with maturation of secondary follicles.
O'Shaughnessy
P J
PJ
Department of Veterinary Physiology, University of Glasgow Veterinary School, UK.
Mannan
M A
MA
D000818:Animals; D000831:Animals, Newborn / Q000378:metabolism*; D001483:Base Sequence; D002786:Cholesterol Side-Chain Cleavage Enzyme / Q000235:genetics*; D018076:DNA, Complementary / Q000737:chemistry; D005260:Female; D007006:Hypogonadism / Q000201:enzymology*; D051379:Mice; D008815:Mice, Inbred Strains; D008969:Molecular Sequence Data; D010053:Ovary / Q000201:enzymology* / Q000254:growth & development*; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000378:metabolism*; D012194:RNA-Directed DNA Polymerase
D018076:DNA, Complementary; D012333:RNA, Messenger; D002786:Cholesterol Side-Chain Cleavage Enzyme; D012194:RNA-Directed DNA Polymerase