The temporal and spatial expression of cytochrome P450 side-chain cleavage (CYP11A1) and cytochrome P450 17α-hydroxylase (CYP17) mRNA and protein during thecal cell differentiation in developing hamster ovaries were evaluated by reverse transcription-polymerase chain reaction (RT-PCR) and immunofluorescence histochemistry, respectively. Ovaries were collected from 15-day fetal through 20-day-old postnatal hamsters and used either for immunofluorescence detection of enzyme protein or RT-PCR evaluation of enzyme mRNA. Immunoreactivity of CYP11A1 first appeared in the interstitial cells on Day 10 postnatal (PN), and the intensity increased significantly with further ovarian development beyond 11 days of age. In contrast, CYP17 immunostaining was first detected in a few interstitial cells closer to large preantral follicles by Day 12 PN, and their number increased appreciably by Day 14 PN. By age 18–20 days, CYP17-positive cells were localized primarily in the thecal layer of large preantral follicles. A low level of CYP17 and CYP11A1 mRNA was present in fetal ovaries. The CYP17 mRNA levels increased sharply by Day 1 PN but decreased to a low baseline level by Day 2 PN and remained low up to Day 9 PN. Both CYP11A1 and CYP17 mRNA levels increased significantly by Day 10 PN compared to Day 9 PN; however, the increase for CYP11A1 was greater than CYP17. The CYP11A1 mRNA levels decreased noticeably on Day 11 PN and remained relatively stable until Day 14 PN; however, mRNA levels started increasing by Day 15 PN and increased sharply by Day 17 PN onward, corresponding to the increase in CYP11A1 protein in the ovarian interstitium and thecal compartments. On the other hand, CYP17 mRNA expression increased progressively through Day 12 PN. A sharp increase in CYP17 mRNA was noted on Day 13 PN in conjunction with the morphological development of thecal cells; mRNA levels remained steady afterward. The correlation of the increase in enzyme mRNA and protein, especially of CYP17, with the morphological development of thecal layers suggests that the differentiation of interstitial cells into theca may be modulated by multilayered preantral follicles, and the expression of enzyme protein occurs prior to an increase in serum LH.
You have requested a machine translation of selected content from our databases. This functionality is provided solely for your convenience and is in no way intended to replace human translation. Neither BioOne nor the owners and publishers of the content make, and they explicitly disclaim, any express or implied representations or warranties of any kind, including, without limitation, representations and warranties as to the functionality of the translation feature or the accuracy or completeness of the translations.
Translations are not retained in our system. Your use of this feature and the translations is subject to all use restrictions contained in the Terms and Conditions of Use of the BioOne website.