Evidence against a role for ovarian hormones in the regulation of blood flow

Objective: To determine the effect of ovarian hormone deficiency on peripheral vascular function. Design: Randomized, single-blind, placebo-controlled. Setting: General clinical research center. Patient(s): Twelve healthy, lean, premenopausal women with regular menstrual cycles. Intervention(s): Measurements were made during the early to midfollicular and midluteal phases of the menstrual cycle. Patients were then randomized to an 8-week course of gonadotropin-releasing hormone agonist (GnRHa) (n = 6) or placebo (n = 6) and retested. On each occasion, blood flow was assessed in the basal postabsorptive state and under euglycemic-hyperinsulinemic-hyperaminoacidemic conditions. Main Outcome Measure(s): Calf blood flow by venous occlusion plethsmography. Result(s): No differences in calf blood flow under postabsorptive (1.65 +/- 0.09 vs. 1.73 +/- 0.16 mL/100g tissue per minute) or insulin-stimulated conditions (2.24 +/- 0.20 vs. 2.30 +/- 0.18 mL/100 g tissue per minute) between the follicular and luteal phases of the menstrual cycle, respectively; therefore, pretreatment data were averaged. Ovarian hormone suppression did not alter postabsorptive calf blood flow (GnRHa: 1.68 +/- 0.13 to 1.69 +/- 0.15; placebo: 1.69 +/- 0.21 to 1.64 +/- 0.14 mL/100 g tissue per minute) or the blood flow response to insulin infusion (GnRHa: 2.40 +/- 0.21 to 2.37 +/- 0.29; placebo 2.10 +/- 0.28 to 2.19 +/- 0.35 mL/100 g tissue per minute). Conclusion(s): Variation in ovarian hormones associated with the menstrual cycle or short-term ovarian hormone deficiency induced by GnRHa do not affect calf blood flow under postabsorptive conditions or the response to hyperinsulemia.