Effects of Metformin on Spontaneous and Clomiphene-Induced Ovulation in the Polycystic Ovary Syndrome

ABSTRACT Background Obese women with the polycystic ovary syndrome are relatively unresponsive to the induction of ovulation by clomiphene. We hypothesized that reducing insulin secretion by administering metformin would increase the ovulatory response to clomiphene. Methods We performed oral glucose-tolerance tests before and after the administration of 500 mg of metformin or placebo three times daily for 35 days in 61 obese women with the polycystic ovary syndrome. Women who did not ovulate spontaneously were then given 50 mg of clomiphene daily for five days while continuing to take metformin or placebo. Serum progesterone was measured on days 14, 28, 35, 44, and 53, and ovulation was presumed to have occurred if the concentration exceeded 8 ng per milliliter (26 nmol per liter) on any of these days. Results Twenty-one women in the metformin group and 25 women in the placebo group were given clomiphene because they did not ovulate spontaneously during the first phase of the study. Among the 21 women given metformin plus clomiphene, the mean (±SE) area under the serum insulin curve after oral glucose administration decreased from 6745±2021 to 3479±455 µU per milliliter per minute (40.5±12.1 to 20.9±2.7 nmol per liter per minute, P=0.03), but it did not change significantly in the 25 women given placebo plus clomiphene. Nineteen of the 21 women (90 percent) who received metformin plus clomiphene ovulated (mean peak serum progesterone concentration, 23.8±3.4 ng per milliliter [7.6±10.9 nmol per liter]). Two of the 25 women (8 percent) who received placebo plus clomiphene ovulated (P\u3c0.001). Overall, 31 of the 35 women (89 percent) treated with metformin ovulated spontaneously or in response to clomiphene, as compared with 3 of the 26 women (12 percent) treated with placebo. Conclusions The ovulatory response to clomiphene can be increased in obese women with the polycystic ovary syndrome by decreasing insulin secretion with metformin. (N Engl J Med 1998;338:1876-80.

Distinct sites of opiate reward and aversion within the midbrain identified using a herpes simplex virus vector expressing GluR1

Repeated administration of morphine increases expression of GluR1 (an AMPA glutamate receptor subunit) in the ventral tegmental area (VTA) of the midbrain, an important neural substrate for the rewarding actions of morphine. Microinjections of a herpes simplex virus (HSV) vector that causes local overexpression of GluR1 (HSV-GluR1) into the VTA can enhance the ability of morphine to establish conditioned place preferences, suggesting that altered GluR1 expression in this region is directly associated with changes in the rewarding efficacy of morphine. We now report that in rats given HSV-GluR1 directly into the VTA, morphine is most rewarding when maximal transgene expression is in the rostral VTA, whereas morphine is aversive when maximal transgene expression is in the caudal VTA. Dual-labeling immunohistochemistry shows that this difference cannot be explained by a different fraction of dopaminergic neurons infected in the rostral versus caudal VTA. No such anatomical specificity is seen in rats given VTA microinjections of HSV-LacZ, a vector expressing a control protein (beta-galactosidase). These results suggest that distinct substrates within the VTA itself differentially contribute to the rewarding and aversive properties of opiates

Ovulatory and metabolic effects of D-chiro-inositol in the polycystic ovary syndrome

BACKGROUND Women with the polycystic ovary syndrome have insulin resistance and hyperinsulinemia, possibly because of a deficiency of a d-chiro-inositol–containing phosphoglycan that mediates the action of insulin. We hypothesized that the administration of d-chiro-inositol would replenish stores of the mediator and improve insulin sensitivity. METHODS We measured steroids in serum and performed oral glucose-tolerance tests before and after the oral administration of 1200 mg of d-chiro-inositol or placebo once daily for six to eight weeks in 44 obese women with the polycystic ovary syndrome. The serum progesterone concentration was measured weekly to monitor for ovulation. RESULTS In the 22 women given d-chiro-inositol, the mean (±SD) area under the plasma insulin curve after the oral administration of glucose decreased from 13,417±11,572 to 5158±6714 μU per milliliter per minute (81±69 to 31±40 nmol per liter per minute) (P=0.007; P=0.07 for the comparison of this change with the change in the placebo group); glucose tolerance did not change significantly. The serum free testosterone concentration in these 22 women decreased from 1.1±0.8 to 0.5±0.5 ng per deciliter (38±28 to 17±17 pmol per liter) (P=0.006 for the comparison with the change in the placebo group). The women\u27s diastolic and systolic blood pressure decreased by 4 mm Hg (Pchiro-inositol ovulated, as compared with 6 of the 22 women in the placebo group (P\u3c0.001). CONCLUSIONS d-Chiro-inositol increases the action of insulin in patients with the polycystic ovary syndrome, thereby improving ovulatory function and decreasing serum androgen concentrations, blood pressure, and plasma triglyceride concentrations

Ultrasound detection by clupeiform fishes

It has previously been shown that at least one species of fish ~the American shad! in the order clupeiforms ~herrings, shads, and relatives! is able to detect sounds up to 180 kHz. However, it has not been clear whether other members of this order are also able to detect ultrasound. It is now demonstrated, using auditory brainstem response ~ABR!, that at least one additional species, the gulf menhaden ~Brevoortia patronus!, is able to detect ultrasound, while several other species including the bay anchovy ~Anchoa mitchilli!, scaled sardine ~Harengula jaguana!, and Spanish sardine ~Sardinella aurita! only detect sounds to about 4 kHz. ABR is used to confirm ultrasonic hearing in the American shad. The results suggest that ultrasound detection may be limited to one subfamily of clupeiforms, the Alosinae. It is suggested that ultrasound detection involves the utricle of the inner ear and speculate as to why, despite having similar ear structures, only one group may detect ultrasound

Phase-field approach to heterogeneous nucleation

We consider the problem of heterogeneous nucleation and growth. The system is described by a phase field model in which the temperature is included through thermal noise. We show that this phase field approach is suitable to describe homogeneous as well as heterogeneous nucleation starting from several general hypotheses. Thus we can investigate the influence of grain boundaries, localized impurities, or any general kind of imperfections in a systematic way. We also put forward the applicability of our model to study other physical situations such as island formation, amorphous crystallization, or recrystallization.Comment: 8 pages including 7 figures. Accepted for publication in Physical Review

Dnmt3a regulates emotional behavior and spine plasticity in the nucleus accumbens.

Despite abundant expression of DNA methyltransferases (Dnmts) in brain, the regulation and behavioral role of DNA methylation remain poorly understood. We found that Dnmt3a expression was regulated in mouse nucleus accumbens (NAc) by chronic cocaine use and chronic social defeat stress. Moreover, NAc-specific manipulations that block DNA methylation potentiated cocaine reward and exerted antidepressant-like effects, whereas NAc-specific Dnmt3a overexpression attenuated cocaine reward and was pro-depressant. On a cellular level, we found that chronic cocaine use selectively increased thin dendritic spines on NAc neurons and that DNA methylation was both necessary and sufficient to mediate these effects. These data establish the importance of Dnmt3a in the NAc in regulating cellular and behavioral plasticity to emotional stimuli

The Short-Term Effect of Video Editing Pace on Children’s Inhibition and N2 and P3 ERP Components during Visual Go/No-Go Task

We investigated the immediate consequences of differently paced videos on behaviour and neural activity during response inhibition. Forty 7-year-olds watched a fast- or slow-paced video and completed a go/no-go task. Compared to the slow-paced-video group, children in the fast-paced-video group made more no-go errors. There was also an interaction between pace and no-go response type (correct, wrong) for the N2 and P3 peak latencies. In the slow-paced group, both components peaked earlier for correct response withholds. This usual pattern of activation was absent in the fast-paced group. Video pace appears to affect behaviour and the neural responses involved in inhibition