Androgen Receptor Blocker Improves the Cardiometabolic Profile in a Rat Model of Polycystic Ovary Syndrome, but at What Cost?

Abstract

Introduction: Polycystic ovary syndrome (PCOS) is the most common endocrine disorder in women of reproductive age. PCOS is characterized by androgen excess and ovulatory dysfunction high prevalence of cardiovascular risk factors such as increased blood pressure (BP), insulin resistance (IR), and obesity. We have demonstrated previously that exposing prepubertal female rats to dihydrotestosterone (DHT) leads to increase in food intake (FI), body weight (BW), BP, and IR. We tested the hypothesis that administration of the AR blocker bicalutamide (BICA) would decrease BP, IR, and obesity in PCOS model. As there are previous reports of severe hepatotoxicity with the AR blocker flutamide, we also examined BICA effects in the liver. Methods: Four-week old female Sprague Dawley rats implanted with DHT pellets (7.5mg/90 days) or placebo (PBO) were randomized to standard chow diet with or without the AR blocker bicalutamide (BICA) at a dose of 250 mg/kg/day throughout the study (n=10/group). BW and FI were measured weekly. BP and heart rate (HR) were measured by radiotelemetry. Fasting plasma was collected for IR (Homeostatic model assessment for IR, HOMA-IR). At euthanasia, the liver was collected, as well as plasma for gamma glutamyl transferase (GGT), alanine transaminase (ALT), and aspartate transaminase (AST) quantification. Results: PCOS rats had increased BW, FI, IR, and BP compared to PBO. BICA treatment had no impact on BW (285.3 ± 7.0 vs 270 ± 8.2 g, P=0.2) as well as FI and HR in PCOS. However, in PCOS, BICA decreased HOMA-IR (5.10 ± 0.40 vs 3.33 ± 0.31, P<0.05) and BP (115.4 ± 0.7 vs 105.3 ± 0.2 mmHg, P<0.01). Compared to PBO, PCOS+BICA rats had similar IR (3.83 ± 0.28 vs 3.33 ± 0.31, P=0.7) and BP (107.4 ± 0.8 vs 105.3 ± 0.2 mmHg, P=0.9). In addition, the liver weight to tibia length ratio was drastically increased by BICA in PCOS (222.9 ± 9.5 vs 360.4 ± 16.9 mg/mm, P<0.0001) as well as GGT (0.88 ± 0.88 vs 11.67 ± 0.58 U/L, P<0.0001), though it decreased AST (60.2 ± 6.9 vs 42.4 ± 1.9 U/L, P<0.05) and had no impact on ALT. Conclusion: In summary, in a model of PCOS, BICA treatment abolished IR and BP, independent of FI, BW and HR. Prompt treatment with an AR blocker can normalize increased IR and BP triggered by androgen excess in females. Further studies need to be done to fully understand the effect of BICA in the liver in PCOS. The beneficial effect of AR blockers as a therapeutic option to improve the cardiometabolic profile in PCOS may be hampered by its liver toxicity.