Stimulation of lactate production in human granulosa cells by metformin and potential involvement of adenosine 5' monophosphate-activated protein kinase.

CONTEXT: Production of 3-carbon units (as lactate) by granulosa cells (GCs) is important in follicular and oocyte development and may be modulated by metformin. OBJECTIVE: The aim of the study was to examine the action of metformin on GC lactate production and potential mediation via AMP-activated protein kinase (AMPK). DESIGN: GCs were prepared from follicular aspirates. After exposure to metformin and other potential modulators of AMPK in culture, aspects of cellular function were examined. SETTING: The study was conducted in a private fertility clinic/university academic center. PATIENTS: Women undergoing routine in vitro fertilization participated in the study. INTERVENTIONS: All agents were added in culture. MAIN OUTCOME MEASURES: Lactate output of GCs was measured. Cell extracts were prepared after culture, and phosphorylated forms of AMPK and acetyl CoA carboxylase (ACC) were assayed using Western analysis. RESULTS: Metformin led to a rapid increase in lactate production by GCs [minimum effective dose, 250 microm; maximum dose studied, 1 mm (1.22-fold; P < 0.01)]. This dose range of metformin was similar to that required for stimulation of phospho-AMPK in GCs [minimum effective dose, 250 microm; maximum effect, 500 microm (2.01-fold; P < 0.001)]. Increasing phospho-ACC, as a representative downstream target regulated by AMPK, was apparent over a lower range (minimum effective dose, 31 microm; maximum effect, 250 microm; P < 0.001). A level of metformin (125 microm) insufficient for the stimulation of lactate output when used alone potentiated the effects of suboptimal doses of insulin on lactate production. Adiponectin (2.5 microg/ml) had a small but significant effect on lactate output. CONCLUSIONS: Metformin activates AMPK in GCs, stimulating lactate production and increasing phospho-ACC. Metformin also enhances the action of suboptimal insulin concentrations to stimulate lactate production.

Effects of the selective progesterone receptor modulator asoprisnil on uterine artery blood flow, ovarian activity, and clinical symptoms in patients with uterine leiomyomata scheduled for hysterectomy.

INTRODUCTION: Asoprisnil, a novel orally active selective progesterone receptor modulator, is being studied for the management of symptomatic uterine leiomyomata. The exact mechanism of action is not yet discerned. The primary objectives of this double-blind, randomized, placebo-controlled study included evaluation of the effect of asoprisnil on uterine artery blood flow. Furthermore, we assessed effects of asoprisnil on leiomyoma symptoms. PATIENTS AND METHODS: Thirty-three premenopausal patients scheduled for hysterectomy due to symptomatic uterine leiomyomata were recruited in four centers and treated with 10 or 25 mg asoprisnil or placebo for 12 wk before surgery. At baseline and before hysterectomy, all patients underwent sonographic assessment to measure impedance to uterine artery blood flow, determined by resistance index and pulsatility index, as well as volumes of largest leiomyoma and uterus. In addition, patients recorded intensity and frequency of menstrual bleeding on a menstrual pictogram. Each asoprisnil treatment was compared with placebo. RESULTS: The increased pulsatility index in both asoprisnil groups and the statistically significantly increased resistance index within the 25-mg asoprisnil group suggest a moderately decreased uterine artery blood flow. Analysis of menstrual pictogram scores showed a statistically significant larger decrease in frequency and intensity of bleeding for both asoprisnil groups compared with placebo. Bleeding was suppressed by asoprisnil 25mg in 91% of patients. Asoprisnil treatment was well tolerated when administered daily for a 12-wk period, and no serious adverse events occurred. CONCLUSION: Asoprisnil moderately reduced uterine artery blood flow. This effect may contribute in part to the clinical effects of asoprisnil.