Doxazosin blockade of α1-adrenergic receptors increases rat serum progesterone levels: a putative role of ovarian angiotensin III in steroidogenesis

ObjectiveTo analyze the role of the local renin-angiotensin system (RAS) in the female reproductive system to modulate ovarian steroidogenesis and its relationship with α1adrenergic receptors.DesignObservational study.SettingUniversity laboratory.Animal(s)Adult female Wistar rats treated with doxazosin (10 mg/kg) or vehicle for 15 days.Intervention(s)Samples from the whole right ovary were dissected after perfusion with saline. The soluble and membrane-bound fractions were obtained from these samples. Also, blood samples were used to obtain the serum.Main Outcome Measure(s)Fluorometric measurement of soluble and membrane-bound RAS-regulating proteolytic regulatory enzyme activities by using arylamide derivatives as substrates. Time-resolved fluoroimmunoassay of serum E2 and P.Result(s)α1Adrenergic receptor blockade increases ovarian soluble and membrane-bound aminopeptidase A and decreases membrane-bound aminopeptidase N and aminopeptidase B. Furthermore, serum P levels increased, whereas serum E2 did not change.Conclusion(s)Ovarian P production, at least in the rat, is regulated by noradrenaline through a mechanism of action in which the RAS is involved, with a main role for angiotensin III.