Investigation of hypothalamo-pituitary-gonadal axis and glucose intolerance among the first-degree female relatives of women with polycystic ovary syndrome

Objective: To assess the glucose intolerance and the hypothalamo-pituitary-gonadal (HPG) axis in the first-degree relatives (FDRs) of patients with polycystic ovary syndrome (PCOS). Design: Clinical study of the female FDRs of patients with PCOS. Setting: Outpatients at endocrinology department of a university hospital. Patient(s): Seventy FDRs of PCOS patients and 20 healthy women were evaluated. Intervention(s): Basal hormonal investigations, buserelin test, and 75-g oral glucose tolerance test (OGTT) were performed. Main Outcome Measure(s): Basal hormone levels were measured. Additionally, insulinogenic index, glucose and insulin responses to OGTT, and FSH, LH, E2, and 17-OHP responses to buserelin test were obtained. Result(s): Four (5.7%) of the FDRs showed impaired glucose tolerance, and the FDRs had significantly higher fasting plasma glucose (P<.05) and basal insulin (P<.01) than control subjects. Peak and area-under-the-curve (AUC) insulin (P<.001) and AUC glucose (P<.05) responses to OGTT were also significantly higher in the FDRs than in control subjects. The FDRs showed higher insulinogenic index than the control subjects (P<.001). The FDRs had significantly (P<.05) higher LH and DHEAS levels and lower (P<.005) 17-OHP levels than the control subjects. Peak (P<.05) and AUC (P<.01) LH responses to buserelin testing were lower in the FDRs than in the control subjects while peak (P<.05) and AUC (P<.01) E2 responses to buserelin were higher in the FDRs than in the control subjects. Conclusion(s): These data support the hypothesis that FDRs of PCOS patients may have insulin resistance and the HPG axis is more susceptible than in control subjects. The FDRs also have an increased prevalence of hyperandrogenism and high DHEAS levels compared with the background population. © 2007 American Society for Reproductive Medicine

Effects of pinealectomy on the levels and the circadian rhythm of plasma homocysteine in rats

Hyperhomocysteinemia is an independent cardiovascular risk factor. There are several factors including aging that contribute to the development of hyperhomocysteinemia. Nevertheless, the exact mechanisms causing this condition are still debated. We hypothesize that the age-related decrease in melatonin levels may be consequential in hyperhomocysteinemia. Recently, we found that plasma homocysteine (Hcy) levels are increased in pinealectomized (PINX) rats and melatonin reverses this increase. The aim of the present study was to determine if there is a circadian rhythm of plasma Hcy in rats and to examine the effect of pinealectomy on this cycle. Plasma Hcy levels demonstrated a 24-hr rhythm with a peak at 02:00 hr and a nadir at 14:00 hr in both control and PINX rats. Pinealectomy did not change the phase of the rhythm or the nocturnal elevation of plasma Hcy, but it did significantly increase mean plasma Hcy levels compared with those in controls and in rats that were sham pinealectomized (sPINX) (P Hyperhomocysteinemia is an independent cardiovascular risk factor. There are several factors including aging that contribute to the development of hyperhomocysteinemia. Nevertheless, the exact mechanisms causing this condition are still debated. We hypothesize that the age-related decrease in melatonin levels may be consequential in hyperhomocysteinemia. Recently, we found that plasma homocysteine (Hcy) levels are increased in pinealectomized (PINX) rats and melatonin reverses this increase. The aim of the present study was to determine if there is a circadian rhythm of plasma Hcy in rats and to examine the effect of pinealectomy on this cycle. Plasma Hcy levels demonstrated a 24-hr rhythm with a peak at 02:00 hr and a nadir at 14:00 hr in both control and PINX rats. Pinealectomy did not change the phase of the rhythm or the nocturnal elevation of plasma Hcy, but it did significantly increase mean plasma Hcy levels compared with those in controls and in rats that were sham pinealectomized (sPINX) (P &lt; 0.05). Melatonin decreases plasma Hcy levels while causing an increase in total glutathione (tGSH). In conclusion, we speculate that decreasing levels of melatonin during aging lead to hyperhomocysteinemia and a decrease in tGSH and the latter may be one of the factors causing hyperhomocysteinemia in the elderly population.</p

Effects of pinealectomy on the circadian release pattern of leptin in male rat

OBJECTIVES: Exogenous and endogenous melatonin decrease leptin release. It is not known whether melatonin also has an effect on circadian release pattern of leptin. So, this study was planned to investigate the possible changes in the circadian release of leptin following pinealectomy