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- Benthin, G, et al.
(författare)
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Transformation of subcutaneous nitric oxide into nitrate in the rat
- 1997
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Ingår i: The Biochemical journal. - : Portland Press Ltd.. - 0264-6021 .- 1470-8728. ; 323323 ( Pt 3), s. 853-858
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Tidskriftsartikel (refereegranskat)abstract
- Following its addition to arterialized blood in vitro, nitric oxide (NO) is transformed into nitrate in the erythrocytes. Inhaled NO is similarly transformed into nitrate in the blood in vivo. These observations suggest that nitrate is a universal end-metabolite of NO, i.e. of endogenously formed NO as well. However, endogenous NO may also be inactivated in tissues, i.e. outside the vascular lumen. To study the fate of NO metabolized with delayed access to the blood, rats were given subcutaneous injections of 15NO or K15NO3, and the plasma concentrations of 15NO3- were followed for 450 min after injection. The values for the distribution volume and plasma decay (t½) of 15NO3- did not differ between rats given 15N-labelled NO and NO3-. The area under the plasma decay curve for rats given 15NO amounted to 89% of the corresponding area for animals given K15NO3. This demonstrates that 15NO, when given extravascularly in millimolar concentrations, is mainly transformed into 15N-labelled nitrate. Other rats were kept in an atmosphere containing a mixture of 16O2 and 18O2. Nitrate residues containing either one or two 18O atoms were isolated from the blood, indicating that inhaled oxygen was incorporated during both the formation of NO and the subsequent transformation of NO into nitrate. The fraction of nitrate residues containing two 18O atoms was larger than that containing one 18O atom. We propose that nitrate is a major stable metabolite of endogenous NO that does not primarily diffuse into the vascular lumen following formation. Hence nitrate seems to be the quantitatively most important end-product of the metabolism of endogenous NO. The transformation of endogenous NO into nitrate involves the incorporation of inhaled oxygen.
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- Sigurjónsdóttir, Helga A, 1964, et al.
(författare)
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Unilateral adrenal hyperplasia is a usual cause of primary hyperaldosteronism. Results from a Swedish screening study.
- 2012
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Ingår i: BMC endocrine disorders. - : Springer Science and Business Media LLC. - 1472-6823. ; 12:1
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Tidskriftsartikel (refereegranskat)abstract
- ABSTRACT: BACKGROUND: The existence of unilateral adrenal hyperplasia (AH) has been considered a rare cause of primary hyperaldosteronism (PA). METHODS: In a prospective study we screened for PA in a non-selected (NSP) and selected hypertensive population (SP), to define the cause of PA. We included 353 consecutive patients with hypertension; age 20 to 88 years, 165 women and 188 men, from a university-based Hypertension and Nephrology Outpatient clinics (123 SP) and two primary care centres, (230 NSP) from the same catch-up area. Serum aldosterone and plasma renin activity (PRA) were measured and the ARR calculated. Verifying diagnostic procedure was performed in patients with both elevated aldosterone and ARR. Patients diagnosed with PA were invited for adrenal venous sampling (AVS) and offered laparoscopic adrenalectomy when AVS found the disease to be unilateral. RESULTS: After screening, 46 patients, 13% of the whole population (22.8% SP and 7.8% NSP) had aldosterone and ARR above the locally defined cut-off limits (0.43 nmol/l and 1.28 respectively). After diagnostic verification, 20 patients (6%) had PA, (14.5% SP and 1.4% NSP). Imaging diagnostic procedures with CT-scans and scintigraphy were inconclusive. AVS, performed in 15 patients verified bilateral disease in 4 and unilateral in 10 patients. One AVS failed. After laparoscopic adrenalectomy, 4 patients were found to have adenoma and 5 unilateral AH. One patient denied operation. CONCLUSION: The prevalence of PA was in agreement with previous studies. The study finds unilateral PA common and unilateral AH as half of those cases. As may be suspected PA is found in much higher frequency in specialised hypertensive units compared to primary care centers. AVS was mandatory in diagnosis of unilateral PA.
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