| 1. |
- Ortega, I., et al.
(författare)
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Letrozole increases ovarian growth and Cyp17a1 gene expression in the rat ovary
- 2013
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Ingår i: Fertility and Sterility. - : Elsevier BV. - 0015-0282. ; 99:3, s. 889-896
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Tidskriftsartikel (refereegranskat)abstract
- Objective: To evaluate the effects of letrozole on ovarian size and steroidogenesis in vivo, as well as Design: In vivo and in vitro studies. Setting: Research laboratory. Animal(s): Immature Sprague-Dawley female rats. Intervention(s): In vivo effects of letrozole were studied in intact rats receiving either letrozole (90-day Main Outcome Measure(s): Deoxyribonucleic acid synthesis was determined by thymidine Result(s): In vivo, letrozole induced an increase in ovarian size compared with the control group and Conclusion(s): These findings suggest that letrozole exerts potent, but indirect, effect on growth of rat
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| 2. |
- Benrick, Anna, 1979, et al.
(författare)
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Resveratrol Is Not as Effective as Physical Exercise for Improving Reproductive and Metabolic Functions in Rats with Dihydrotestosterone-Induced Polycystic Ovary Syndrome
- 2013
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Ingår i: Evidence-Based Complementary and Alternative Medicine. - : Hindawi Limited. - 1741-427X .- 1741-4288.
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Tidskriftsartikel (refereegranskat)abstract
- Polycystic ovary syndrome (PCOS) is a reproductive and metabolic disorder associated with obesity and insulin resistance that often precedes the development of type-2 diabetes. Rats continuously exposed to dihydrotestosterone from prepuberty display typical reproductive and metabolic PCOS characteristics including anovulation, polycystic ovaries, insulin resistance, and obesity. Our aim was to investigate if resveratrol improves reproductive and metabolic functions in PCOS rats. The effect was compared to exercise. Control and PCOS rats were treated with vehicle or resveratrol (400mg·kg−1·day−1) for 5-6 weeks. Another group of PCOS rats received vehicle treatment and exercised for 5-6 weeks. Insulin sensitivity was determined by euglycemic-hyperinsulinemic clamp. The glucose infusion rate was lower in the PCOS-vehicle group compared to control-vehicle rats (). Exercise increased insulin sensitivity compared with PCOS-vehicle rats (), but resveratrol did not. Resveratrol treatment and exercise resulted in smaller adipocytes, upregulated estrogen-related receptor α gene expression in subcutaneous fat, and improved estrus cyclicity in the previously acyclic PCOS rats. Although resveratrol had positive effects on adiposity and cyclicity in a similar manner to exercise, resveratrol does not seem to be a good candidate for treating insulin resistance associated with PCOS because no improvement in insulin sensitivity was observed in PCOS rats on normal chow.
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| 3. |
- Riedl, Stephan, et al.
(författare)
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Hypothesis: Persistently Elevated hCG Causes Gestational Ovarian Overstimulation Associated With Prolonged Postpartum Hyperandrogenism in Mothers of Aromatase-Deficient Babies.
- 2013
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Ingår i: Journal of Clinical Endocrinology and Metabolism. - : The Endocrine Society. - 0021-972X .- 1945-7197. ; 98:8
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Tidskriftsartikel (refereegranskat)abstract
- Context:Aromatase deficiency due to a CYP19A1 defect leads to fetoplacental inability to convert androgens into estrogens. Pregnant mothers experience virilization caused by excess nonaromatized fetal androgens entering the maternal circulation. Biochemical normalization is believed to take place shortly after delivery.Objective:We report prolonged postnatal hyperandrogenism and enlarged multicystic ovaries in the mother of an affected 46,XX infant and hypothesize a possible pathogenetic mechanism.Patients and Methods:We investigated the mother on days 12 and 20 after delivery. FSH, LH, T, estradiol (E2), androstenedione (A), dehydroepiandrosterone-sulfate (DHEA-S), and human chorionic gonadotropin (hCG) plasma levels were obtained, and ovarian ultrasonography and magnetic resonance imaging were performed.Results:T (1040 ng/dL), A (6940 ng/dL), and E2 (2787 pg/mL) levels were markedly elevated on day 12 after delivery, whereas LH and FSH were suppressed (<0.1 IU/L). On day 20, all hormones had decreased significantly; however, T, A, and E2 still remained 3.5-, 2.2-, and 1.4-fold elevated, respectively, as compared to upper reference values. hCG (18.9 U/L) was still increased. DHEA-S was normal on both occasions. Sonography and magnetic resonance imaging revealed enlarged ovaries, with several cysts up to 4 cm. There was no history of polycystic ovary syndrome.Conclusions:We hypothesize that persistent ovarian overstimulation by hCG had occurred in the mother during pregnancy, leading to prolonged autonomous excess production of androgens during the first weeks after delivery. As a causative mechanism, we propose that gestational hyperandrogenism and hypoestrogenism reduced inhibition of placental GnRH and hCG secretion by progesterone, resulting in persistently elevated hCG.
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| 4. |
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| 5. |
- Maliqueo, Manuel, et al.
(författare)
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Continuous Administration of a P450 Aromatase Inhibitor Induces Polycystic Ovary Syndrome with a Metabolic and Endocrine Phenotype in Female Rats at Adult Age
- 2013
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Ingår i: Endocrinology. - : The Endocrine Society. - 0013-7227 .- 1945-7170. ; 154:1, s. 434-445
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Tidskriftsartikel (refereegranskat)abstract
- Studying the mechanisms for the complex pathogenesis of polycystic ovary syndrome (PCOS) requires animal models with endocrine, reproductive, and metabolic features of the syndrome. Hyperandrogenism seems to be a central factor in PCOS, leading to anovulation and insulin resistance. In female rats, continuous administration of letrozole, a nonsteroidal inhibitor of P450 aromatase, at 400 mu g/d starting before puberty induces hyperandrogenemia and reproductive abnormalities similar to those in women with PCOS. However, despite high circulating testosterone levels, these rats do not develop metabolic abnormalities, perhaps because of their supraphysiological testosterone concentrations or because estrogen synthesis is completely blocked in insulin-sensitive tissues. To test the hypothesis that continuous administration of lower doses of letrozole starting before puberty would result in both metabolic and reproductive phenotypes of PCOS, we performed a 12-wk dose-response study. At 21 d of age, 46 female Wistar rats were divided into two letrozole groups (100 or 200 mu g/d) and a control group (placebo). Both letrozole doses resulted in increased body weight, inguinal fat accumulation, anovulation, larger ovaries with follicular atresia and multiples cysts, endogenous hyperandrogemia, and lower estrogen levels. Moreover, rats that received 200 mu g/d had insulin resistance and enlarged adipocytes in inguinal and mesenteric fat depots, increased circulating levels of LH, decreased levels of FSH, and increased ovarian expression of Cyp17a1 mRNA. Thus, continuous administration of letrozole, 200 mu g/d, to female rats for 90 d starting before puberty results in a PCOS model with reproductive and metabolic features of the syndrome. (Endocrinology 154: 434-445, 2013)
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