| 1. |
- Kirilovas, Dmitrijus, et al.
(författare)
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Granulosa cell aromatase enzyme activity : Effects of follicular fluid from patients with polycystic ovary syndrome, using aromatase conversion and [11C]vorozole-binding assays
- 2006
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Ingår i: Gynecological Endocrinology. - : Informa UK Limited. - 0951-3590 .- 1473-0766. ; 22:12, s. 685-691
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Tidskriftsartikel (refereegranskat)abstract
- The local regulation of ovarian aromatase enzyme in polycystic ovary syndrome (PCOS) was studied with aromatase conversion and [C-11]vorozole-binding assays to analyze aromatase activity, substrate-enzyme affinity and number of aromatase binding sites in non-cultured human granulosa cells (GC) incubated with different sources and preparations of follicular fluid (FF). Incubation with FF from women stimulated in in vitro fertilization cycles with follicle-stimulating hormone yielded higher conversion activity than with FF from healthy women and PCOS patients, paralleled with higher substrate affinity (lower K-d) than with FF from healthy women. In PCOS women, charcoal-pretreated FF yielded higher conversion, whereas the ether-pretreated FF yielded lower conversion activity, than with untreated PCOS FF. Both preparations of FF yielded higher affinity to substrate (lower Kd values) and the ether-pretreated FF a lower number of binding sites (B-max). It seems that steroids with the presence of proteins in PCOS FF reduced aromatase conversion activity through decreased substrate affinity, whereas FF preparations devoid of proteins reduced the aromatase conversion activity mainly through blocking of aromatase active sites. Identification of specific agents responsible for this rapid regulation of aromatase function might help to understand normal regulation of the menstrual cycle and supposed imbalances of inhibitors/activators in PCOS.
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| 2. |
- Kushnir, Mark M, et al.
(författare)
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Steroid profiles in ovarian follicular fluid from regularly menstruating women and women after ovarian stimulation
- 2009
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Ingår i: Clinical Chemistry. - : Oxford University Press (OUP). - 0009-9147 .- 1530-8561. ; 55:3, s. 519-526
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Information on the concentrations of steroids in ovarian follicular fluid (FF) from regularly menstruating (RM) women has been limited because of the absence of methods for the simultaneous quantification of multiple steroids in small volumes of FF. We studied steroid profiles in FF during the early follicular phase of the menstrual cycle and after ovarian stimulation for in vitro fertilization (IVF), and compared concentrations with published values obtained by immunoassay (IA). METHODS: We used liquid chromatography-tandem mass spectrometry (LC-MS/MS) to measure 13 steroids in 40-microL aliquots of FF samples from 21 RM women and from 5 women after ovarian stimulation for IVF. Relationships between concentrations of steroids and their ratios (representations of the enzyme activities) were evaluated within and between subgroups. RESULTS: The concentrations of testosterone (Te), androstenedione (A4), and estradiol (E2) measured by LC-MS/MS were lower than those previously reported in studies with IAs. In RM women, androgens were the most abundant class of steroids, with A4 being the major constituent. The concentrations of 17-hydroxyprogesterone (17OHP), total androgens, and estrogens were 200- to 1000-fold greater in FF than in serum. Compared with RM women, FF samples from women undergoing ovarian stimulation had significantly higher concentrations of E2 (P = 0.021), pregnenolone (P = 0.0022), 17OHP (P = 0.0007), and cortisol (F) (P = 0.0016), and significantly higher ratios of F to cortisone (P = 0.0006), E2 to estrone (P = 0.0008), and E2 to Te (P = 0.0013). CONCLUSIONS: The data provide the first MS-based concentration values for 13 steroids in ovarian FF from RM women, from estrogen- and androgen-dominant follicles, and from women after ovarian stimulation for IVF.
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| 3. |
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| 4. |
- Naessén, Tord, et al.
(författare)
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Steroid profiles in ovarian follicular fluid in women with and without polycystic ovary syndrome, analyzed by liquid chromatography-tandem mass spectrometry.
- 2010
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Ingår i: Fertility and Sterility. - : Elsevier BV. - 0015-0282 .- 1556-5653. ; 94:6, s. 2228-2233
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE To compare steroid concentrations and steroid product-to-precursor ratios in ovarian follicular fluid (FF) from women with polycystic ovary syndrome (PCOS) and from regularly menstruating women in their early follicular phase, using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Polycystic ovary syndrome involves abnormal regulation of the steroidogenic enzymes, leading to arrest of follicle development. DESIGN Case-control study. SETTING University hospital clinic. PATIENT(S) Follicular fluid from size-matched ovarian follicles (5-8 mm) in 27 nonstimulated women with PCOS and in 21 women without PCOS was sampled. Thirteen steroids were quantitated from 40 muL of FF, using LC-MS/MS. INTERVENTION(S) None. MAIN OUTCOME MEASURE(S) Concentrations of steroids in the FF and product-to-precursor ratios (enzyme activity) were compared between the groups. RESULT(S) In women with PCOS, ovarian FF contained higher concentrations of individual and total androgens, lower individual and total estrogens (E), and a lower total E-to-androgen ratio, compared with regularly menstruating women. The product-to-precursor concentration ratios indicated higher CYP17-linked and lower CYP19-linked (aromatase) enzyme activity. Receiver operating characteristic plots indicated the early CYP17 step (17-OH5P/5P) being highly important for the prevalence of PCOS (c = 0.95). CONCLUSION(S) The women with PCOS had higher ovarian CYP17-linked and lower CYP19-linked (aromatase) enzyme activity, confirming previous data. Multiple steroid assessments from minute volumes including FF from nonstimulated ovaries, using LC-MS/MS, might be useful in research, clinical endocrinology, and in IVF.
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