Kashinath Dixit

CONTEXT: Posterior pituitary function in patients with suspected diabetes insipidus is usually assessed by a water deprivation test. Alternatively, a nonosmotic stimulus such as hypoglycemia may be used to stimulate vasopressin [arginine vasopressin (AVP)] secretion. Plasma AVP measurement may aid in the diagnosis and, especially, differential diagnosis of diabetes insipidus and polydipsia. However, AVP measurement is cumbersome. Copeptin, the stable C-terminal glycopeptide of the AVP prohormone, is stoichiometrically secreted from the posterior pituitary. OBJECTIVE: The aim was to study the value of copeptin levels in the diagnosis of diabetes insipidus during insulin-induced hypoglycemia. PATIENTS AND METHODS: A total of 38 patients were studied during insulin-induced hypoglycemia as part of a combined pituitary function test for possible anterior pituitary disease. There were 29 patients who had normal posterior pituitary function, and nine had central diabetes insipidus. Blood sampling was done before and 30, 45, and 90 min after iv insulin injection. Copeptin was measured with a new sandwich immunoassay. RESULTS: Patients with intact posterior pituitary function had basal copeptin levels of 3.7 +/- 1.5 pm, with a maximal increase to 11.1 +/- 4.6 pm 45 min after insulin injection. Copeptin levels in patients with diabetes insipidus were 2.4 +/- 0.5 pm before insulin injection, with a maximum increase to 3.7 +/- 0.7 pm. Both basal and stimulated copeptin levels were lower in patients with diabetes insipidus as compared with patients with intact posterior pituitary function. A stimulated copeptin level 45 min after insulin injection of less than 4.75 pm had an optimal diagnostic accuracy to detect diabetes insipidus. CONCLUSION: Copeptin measurement may be used to assess posterior together with anterior pituitary function during insulin-induced hypoglycemia.

CONTEXT: Thyronamines are thyronergic metabolites of thyroid hormones. Lack of reliable and sensitive detection methods for endogenous 3-iodothyronamine (3-T(1)AM) has so far hampered progress in understanding their physiological action and role in endocrine homeostasis or pathophysiology of diseases. OBJECTIVE: We characterized newly generated mouse monoclonal 3-T(1)AM antibodies and established a monoclonal antibody-based chemiluminescence immunoassay as a powerful tool for monitoring 3-T(1)AM levels in investigations addressing altered serum profiles and potential sites of origin and action of 3-T(1)AM in humans. DESIGN AND SETTING: Our exploratory study on 3-T(1)AM serum levels in humans measured 3-T(1)AM concentrations in comparison with thyroid hormones. PATIENTS OR OTHER PARTICIPANTS: Thirteen adult healthy subjects, 10 patients with pituitary insufficiency, and 105 thyroid cancer patients participated. INTERVENTIONS: INTERVENTIONS included l-T(4) withdrawal in patients with pituitary insufficiency as well as TSH-suppressive T(4) substitution in thyroid cancer patients. RESULTS: 3-T(1)AM was reliably quantified in human serum and stable after storage at room temperature and 4 C overnight as well as after four freeze-thaw cycles. The median serum concentration in healthy subjects was 66 ± 26 nm. 3-T(1)AM was also detected in T(4)-substituted thyroid cancer patients. Although free T(4) and T(3) significantly decreased during T(4) withdrawal, 3-T(1)AM levels remained constant for 6 d. CONCLUSION: Because higher 3-T(1)AM levels are detectable in T(4)-substituted thyroid cancer patients after thyroidectomy/radioiodine treatment compared with healthy controls, we concluded that 3-T(1)AM is mainly produced by extrathyroidal tissues. The serum profile during T(4) withdrawal suggests either a long half-life or persisting 3-T(1)AM release into serum from intracellular thyroid hormone precursors or stores.

Copeptin, the C-terminal peptide of provasopressin, is stoichiometrically released with arginine vasopressin (AVP). In contrast to AVP, it is stable ex vivo (1) and reflects the AVP system, as shown in diabetes insipidus or the syndrome of inappropriate antidiuretic hormone secretion(2). Copeptin is a reliable marker of severe stress, with increased concentrations found in cases of critical illness, sepsis, hemorrhagic shock, and stroke(2). The serum copeptin concentration is profoundly and immediately stimulated after myocardial infarction(3). The absence of such stimulation within the first hours after the onset of symptoms has recently been proposed as an important negative predictor for excluding the likelihood of infarction in patients with unspecific chest pain(3). Any further use of the peptide as a marker critically depends on clear cutoffs between health and disease. To better characterize the diagnostic accuracy of …

Aim To re‐evaluate the weight loss efficacy of LI85008F in healthy overweight adults via a 16‐week randomized, double‐blind, placebo‐controlled clinical study. Materials and Methods One hundred and forty overweight participants (body mass index [BMI] 27‐29.9 kg/m 2 , 29.3% male; ages 21‐50 years) were randomized into placebo ( n =70) and LI85008F ( n =70) groups. The participants received either 900 mg/d of LI85008F in two divided doses or two identical placebo capsules. In addition, participants were counselled to follow an ~1800 kcal/d diet and to engage in walking for 30 min, 5 d/wk throughout the study. Results At the end of the trial period, the LI85008F supplemented group showed significant reductions in body weight (5.36 ± 1.769 vs. 0.87 ± 1.381 kg; P < 0.0001) and BMI (2.05 ± 0.693 vs. 0.34 ± 0.559 kg/m 2 ; P < 0.0001), compared with placebo. Significant reductions in waist and hip circumferences, and a 2.08‐fold reduction of waist/hip ratio, were noted in the LI85008F supplemented group. LI85008F supplementation also resulted in significant improvements in lipid profiles, compared with the placebo; low‐density lipoprotein (LDL) cholesterol decreased, while high‐density lipoprotein (HDL) cholesterol increased, resulting in a significantly improved LDL/HDL ratio. No major adverse events were reported by the participants during the study. Conclusions The unique herbal extract blend LI85008F, combined with modest calorie restriction and physical activity, is well tolerated, safe, and effective for weight management in overweight men and women. Video Abstract A free Video Abstract to accompany this article is available at: https://player.vimeo.com/video/288617068 .