Pharmacokinetic factors contribute to the inverse relationship between luteinizing hormone and body mass index in polycystic ovarian syndrome.

Context: Serum LH levels decrease with increasing body mass index (BMI) in women with polycystic ovarian syndrome (PCOS).

Objective: The objective of this study was to determine whether pharmacokinetic factors contribute to the effect of obesity on LH in PCOS. PARTICIPANTS/INTERVENTIONS/SETTING: Twenty-one women with PCOS underwent frequent blood sampling, iv administration of GnRH (75 ng/kg), and sc administration of the NAL-GLU GnRH antagonist (150 microg/kg) followed by iv recombinant human LH (rhLH; 300 IU) in the General Clinical Research Center at an academic medical center.

Inverse relationship between luteinizing hormone and body mass index in polycystic ovarian syndrome: investigation of hypothalamic and pituitary contributions.

Context: Patients with polycystic ovarian syndrome (PCOS) have increased LH relative to FSH, but LH is modified by body mass index (BMI).

Objective: The objective of the study was to determine whether the impact of BMI on neuroendocrine dysregulation in PCOS is mediated at the hypothalamic or pituitary level. PARTICIPANTS/INTERVENTIONS/SETTING: Twenty-four women with PCOS across a spectrum of BMIs underwent frequent blood sampling, iv administration of GnRH (75 ng/kg), and sc administration of the NAL-GLU GnRH antagonist (5 microg/kg) in the General Clinical Research Center at an academic hospital.

Maternal activating mutation of the calcium-sensing receptor: implications for calcium metabolism in the neonate.

Two infants were studied born of a mother with autosomal dominant hypocalcemia who is heterozygous for an activating mutation in the calcium-sensing receptor gene. Both infants had serum calcium levels in the low-normal range and parathyroid hormone levels in the high-normal range and were healthy. The mother's hypocalcemia had been treated with calcium carbonate and calcitriol and she has nephrocalcinosis and mild renal insufficiency.

Control of follicle-stimulating hormone by estradiol and the inhibins: critical role of estradiol at the hypothalamus during the luteal-follicular transition.

To test the hypothesis that estradiol, inhibin A, and inhibin B contribute differentially to FSH negative feedback in specific phases of the menstrual cycle, daily blood samples were obtained across a control cycle and after selective estrogen blockade with tamoxifen. To examine the site of estradiol-negative feedback in control and tamoxifen treatment cycles, early follicular phase GnRH (free alpha-subunit) pulse frequency was assessed in normal women, and FSH levels were examined in GnRH-deficient women in whom hypothalamic output was fixed with GnRH administration. FSH was higher in the early follicular phase in the presence of estrogen receptor blockade (15.