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Takayanagi K, Shimizu T, Tayama Y, Ikari A, Anzai N, Iwashita T, Asakura J, Hayashi K, Mitarai T, Hasegawa H. Downregulation of transient receptor potential M6 channels as a cause of hypermagnesiuric hypomagnesemia in obese type 2 diabetic rats. Am J Physiol Renal Physiol 2015; 308:F1386-97. [DOI: 10.1152/ajprenal.00593.2013] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2013] [Accepted: 12/11/2014] [Indexed: 12/15/2022] Open
Abstract
We assessed the expression profile of Mg2+-transporting molecules in obese diabetic rats as a cause of hypermagnesiuric hypomagnesemia, which is involved in the development of insulin resistance, hypertension, and coronary diseases. Kidneys were obtained from male Otsuka Long-Evans Tokushima fatty (OLETF) and Long-Evans Tokushima Otsuka (LETO) obese diabetic rats at the ages of 16, 24, and 34 wk. Expression profiles were studied by real-time PCR and immunohistochemistry together with measurements of urine Mg2+excretion. Urine Mg2+excretion was increased in 24-wk-old OLETF rats and hypomagnesemia was apparent in 34-wk-old OLETF rats but not in LETO rats (urine Mg2+excretion: 0.16 ± 0.01 μg·min−1·g body wt−1in 24-wk-old LETO rats and 0.28 ± 0.01 μg·min−1·g body wt−1in 24-wk-old OLETF rats). Gene expression of transient receptor potential (TRP)M6 was downregulated (85.5 ± 5.6% in 34-wk-old LETO rats and 63.0 ± 3.5% in 34-wk-old OLETF rats) concomitant with Na+-Cl−cotransporter downregulation, whereas the expression of claudin-16 in tight junctions of the thick ascending limb of Henle was not different. The results of the semiquantitative analysis of immunohistochemistry were consistent with these findings (TRPM6: 0.49 ± 0.04% in 16-wk-old LETO rats, 0.10 ± 0.01% in 16-wk-old OLETF rats, 0.52 ± 0.03% in 24-wk-old LETO rats, 0.10 ± 0.01% in 24-wk-old OLETF rats, 0.48 ± 0.02% in 34-wk-old LETO rats, and 0.12 ± 0.02% in 34-wk-old OLETF rats). Gene expression of fibrosis-related proinflammatory cytokines as well as histological changes showed that the hypermagnesiuria-related molecular changes and tubulointerstitial nephropathy developed independently. TRPM6, located principally in distal convoluted tubules, appears to be a susceptible molecule that causes hypermagnesiuric hypomagnesemia as a tubulointerstitial nephropathy-independent altered tubular function in diabetic nephropathy.
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Affiliation(s)
- Kaori Takayanagi
- Ishikawa Kinenkai Kawagoe Ekimae Clinic, Kawagoe, Saitama, Japan
- Department of Nephrology and Hypertension, Saitama Medical Center, Saitama Medical University, Kawagoe, Saitama, Japan
| | - Taisuke Shimizu
- Department of Nephrology and Hypertension, Saitama Medical Center, Saitama Medical University, Kawagoe, Saitama, Japan
| | - Yosuke Tayama
- Department of Nephrology and Hypertension, Saitama Medical Center, Saitama Medical University, Kawagoe, Saitama, Japan
| | - Akira Ikari
- Laboratory of Biochemistry, Department of Biopharmaceutical Sciences, Gifu Pharmaceutical University, Gifu, Japan; and
| | - Naohiko Anzai
- Department of Pharmacology and Toxicology, Dokkyo Medical University School of Medicine, Tochigi, Japan
| | - Takatsugu Iwashita
- Department of Nephrology and Hypertension, Saitama Medical Center, Saitama Medical University, Kawagoe, Saitama, Japan
| | - Juko Asakura
- Department of Nephrology and Hypertension, Saitama Medical Center, Saitama Medical University, Kawagoe, Saitama, Japan
| | - Keitaro Hayashi
- Department of Pharmacology and Toxicology, Dokkyo Medical University School of Medicine, Tochigi, Japan
| | - Tetsuya Mitarai
- Department of Nephrology and Hypertension, Saitama Medical Center, Saitama Medical University, Kawagoe, Saitama, Japan
| | - Hajime Hasegawa
- Department of Nephrology and Hypertension, Saitama Medical Center, Saitama Medical University, Kawagoe, Saitama, Japan
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The effect of desmopressin on platelet function: a selective enhancement of procoagulant COAT platelets in patients with primary platelet function defects. Blood 2014; 123:1905-16. [DOI: 10.1182/blood-2013-04-497123] [Citation(s) in RCA: 74] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Key PointsDDAVP is the drug of choice for mild hemophilia A and von Willebrand disease and (by unclear mechanisms) for platelet function disorders. In vivo DDAVP selectively and markedly enhances the ability to form procoagulant platelets by enhancing intracellular Na+ and Ca2+ fluxes.
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Juul KV, Erichsen L, Robertson GL. Temporal delays and individual variation in antidiuretic response to desmopressin. Am J Physiol Renal Physiol 2013; 304:F268-78. [DOI: 10.1152/ajprenal.00502.2012] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
This study aimed to estimate the relationship between pharmacokinetics and the antidiuretic effect of desmopressin. In the investigator-blind, randomized, parallel group study, 5 dose groups and 1 placebo group, each consisting of 12 healthy, overhydrated, nonsmoking male subjects 18–55 yr of age were infused intravenously over 2 h with placebo or 30, 60, 125, 250, and 500 ng desmopressin in 50 ml of normal saline. Plasma desmopressin and urine osmolality rose by variable amounts during the infusions of 60, 125, 250, and 500 ng desmopressin. Plotting mean urine osmolality against the concurrent mean plasma desmopressin yielded a temporal delay between pharmacokinetic (PK) and -dynamic (PD) responses in all dose groups. Using simulation from the indirect-response model, assuming a constant (4 ng/ml) desmopressin concentration, this delay between PK and PD was estimated at 4 h (10th-90th percentile: 1.8–8.1). Within each group, however, there were large individual variations (2- to 10-fold) in the magnitude and duration of the antidiuretic effect. The antidiuretic effect of intravenous desmopressin in water-loaded healthy adults varies considerably due largely to factors other than individual differences in pharmacokinetics. The antidiuretic effect is time as well as dose dependent and may be self-amplifying. The most likely explanation for these findings is that the time required for a given level of plasma desmopressin to exert its maximum antidiuretic effect varies markedly from person to person due to individual differences in the kinetics of one or more of the intracellular mechanisms that promote the reabsorption of solute-free water by principal cells in renal collecting tubules.
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Affiliation(s)
| | - Lars Erichsen
- Ferring International Pharmascience Center, Copenhagen, Denmark; and
| | - Gary L. Robertson
- Clinical Research Center at Northwestern Memorial Hospital, Feinberg Medical School of Northwestern University, Chicago, Illinois
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McCabe MJ, Gaston-Massuet C, Tziaferi V, Gregory LC, Alatzoglou KS, Signore M, Puelles E, Gerrelli D, Farooqi IS, Raza J, Walker J, Kavanaugh SI, Tsai PS, Pitteloud N, Martinez-Barbera JP, Dattani MT. Novel FGF8 mutations associated with recessive holoprosencephaly, craniofacial defects, and hypothalamo-pituitary dysfunction. J Clin Endocrinol Metab 2011; 96:E1709-18. [PMID: 21832120 PMCID: PMC3417283 DOI: 10.1210/jc.2011-0454] [Citation(s) in RCA: 101] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/18/2011] [Accepted: 07/12/2011] [Indexed: 11/19/2022]
Abstract
CONTEXT Fibroblast growth factor (FGF) 8 is important for GnRH neuronal development with human mutations resulting in Kallmann syndrome. Murine data suggest a role for Fgf8 in hypothalamo-pituitary development; however, its role in the etiology of wider hypothalamo-pituitary dysfunction in humans is unknown. OBJECTIVE The objective of this study was to screen for FGF8 mutations in patients with septo-optic dysplasia (n = 374) or holoprosencephaly (HPE)/midline clefts (n = 47). METHODS FGF8 was analyzed by PCR and direct sequencing. Ethnically matched controls were then screened for mutated alleles (n = 480-686). Localization of Fgf8/FGF8 expression was analyzed by in situ hybridization in developing murine and human embryos. Finally, Fgf8 hypomorphic mice (Fgf8(loxPNeo/-)) were analyzed for the presence of forebrain and hypothalamo-pituitary defects. RESULTS A homozygous p.R189H mutation was identified in a female patient of consanguineous parentage with semilobar HPE, diabetes insipidus, and TSH and ACTH insufficiency. Second, a heterozygous p.Q216E mutation was identified in a female patient with an absent corpus callosum, hypoplastic optic nerves, and Moebius syndrome. FGF8 was expressed in the ventral diencephalon and anterior commissural plate but not in Rathke's pouch, strongly suggesting early onset hypothalamic and corpus callosal defects in these patients. This was consolidated by significantly reduced vasopressin and oxytocin staining neurons in the hypothalamus of Fgf8 hypomorphic mice compared with controls along with variable hypothalamo-pituitary defects and HPE. CONCLUSION We implicate FGF8 in the etiology of recessive HPE and potentially septo-optic dysplasia/Moebius syndrome for the first time to our knowledge. Furthermore, FGF8 is important for the development of the ventral diencephalon, hypothalamus, and pituitary.
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Affiliation(s)
- Mark J McCabe
- Clinical and Molecular Genetics Unit, University College London—Institute of Child Health, London WC1N 1EH, United Kingdom
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