Combination of peptide YY3-36 with GLP-1(7-36) amide causes an increase in first-phase insulin secretion after IV glucose.

Context: The combination of peptide YY (PYY) and glucagon-like peptide-1 (GLP-1) has been proposed as a potential treatment for diabetes and obesity. However, the combined effects of these hormones, PYY(3-36) and GLP-1(7-36 amide), on glucose homeostasis are unknown.

Objective: This study sought to investigate the acute effects of PYY(3-36) and GLP-1(7-36) amide, individually and in combination, on insulin secretion and sensitivity.

Overlapping dose responses of spermatogenic and extragonadal testosterone actions jeopardize the principle of hormonal male contraception.

Testosterone (T), alone or in combination with progestin, provides a promising approach to hormonal male contraception. Its principle relies on enhanced negative feedback of exogenous T to suppress gonadotropins, thereby blocking the testicular T production needed for spermatogenesis, while simultaneously maintaining the extragonadal androgen actions, such as potency and libido, to avoid hypogonadism. A serious drawback of the treatment is that a significant proportion of men do not reach azoospermia or severe oligozoospermia, commensurate with contraceptive efficacy.

Associations of serum 25-hydroxyvitamin D with circulating PTH, phosphate and calcium in patients with primary hyperparathyroidism.

Background: Despite NIH clinical recommendations, many clinicians are reluctant to replace vitamin D in patients with hypercalcaemia with primary hyperparathyroidism (PHP) due to concerns over aggravating hypercalcaemia. Furthermore, the optimum level of vitamin D replacement in PHP remains unclear.

Methods: We performed a large retrospective study to determine whether a relationship exists between serum 25-hydroxyvitamin D levels, calcium and other important biochemical markers in patients with PHP.

Comparison of the overnight metyrapone and glucagon stimulation tests in the assessment of secondary hypoadrenalism.

Objective: The insulin tolerance test (ITT) is contraindicated in a proportion of patients with suspected ACTH deficiency. The aim of this study was to investigate the diagnostic accuracy of the glucagon stress test (GST) compared with the overnight metyrapone test (OMT) in patients with contraindications to ITT.

Design: This was a prospective comparison of the GST to the OMT in patients with suspected ACTH deficiency and contraindications to the ITT.

Adrenal venous sampling as a diagnostic procedure for primary hyperaldosteronism: experience from a tertiary referral centre.

Context: Adrenal vein sampling (AVS) is recommended in all patients with hyperaldosteronism to whom surgery would be offered if the results indicated unilateral hypersecretion.

Objective: To assess the performance of AVS against radiological findings and to evaluate the Endocrine Society's Practice Guidelines for diagnostic cut-offs.

Patients: Retrospective study of 41 patients with hyperaldosteronism who underwent both AVS and computed tomography (CT) imaging.

Oral cholecalciferol decreases albuminuria and urinary TGF-β1 in patients with type 2 diabetic nephropathy on established renin-angiotensin-aldosterone system inhibition.

The anti-inflammatory, antifibrotic, and antiproteinuric properties of vitamin D have been defined in studies using active vitamin D analogs. In this prospective observational study we determined whether nutritional vitamin D repletion can have additional beneficial effects in patients with type 2 diabetic nephropathy already established on renin-angiotensin-aldosterone system inhibition. During a 7-month period, 63 patients were enrolled and those with low levels of 25(OH)D were treated with oral cholecalciferol for 4 months.

Utility of the urine calcium-to-creatinine ratio to diagnose primary hyperparathyroidism in asymptomatic hypercalcaemic patients with vitamin D deficiency.

Background: Primary hyperparathyroidism (PHP) is the most common cause of hypercalcaemia, and often requires surgical treatment. Familial hypocalciuric hypercalcaemia (FHH) has similar biochemical features to PHP, but requires no treatment. The most common biochemical method used to distinguish between PHP and FHH is the urine calcium-to-creatinine ratio (UCCR).

Subcutaneous injection of kisspeptin-54 acutely stimulates gonadotropin secretion in women with hypothalamic amenorrhea, but chronic administration causes tachyphylaxis.

Background: Kisspeptin is a critical regulator of normal reproductive function. A single injection of kisspeptin in healthy human volunteers potently stimulates gonadotropin release. However, the effects of kisspeptin on gonadotropin release in women with hypothalamic amenorrhea (HA) and the effects of repeated administration of kisspeptin to humans are unknown.

Kisspeptin-54 stimulates gonadotropin release most potently during the preovulatory phase of the menstrual cycle in women.

Context: Kisspeptin, the endogenous ligand of the G protein-coupled receptor 54, is a key regulator of the hypothalamo-pituitary-gonadal (HPG) axis. GPR54-null mice exhibit reproductive dysfunction, and exogenous kisspeptin potently stimulates the HPG axis in rodents, primates, and human males. The effects of kisspeptin administration to human females are unknown.

The relationship between androgens and arterial stiffness in older men.

Objectives: To assess the relationship between endogenous androgen levels and arterial stiffness in older men.

Design: A retrospective, cross-sectional study.

Setting: A London hospital-based, clinical research unit for the elderly.

Testosterone suppression in men with prostate cancer leads to an increase in arterial stiffness and hyperinsulinaemia.

The role of androgens in cardiovascular disease is uncertain. We aimed to determine the vascular effects of androgen suppression in men with prostate cancer. Arterial stiffness (or 'compliance') was measured in 16 men (71+/-9 years, mean+/-S.