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- Bjorck, L., et al.
(författare)
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A deletion in a rat major histocompatibility complex class I gene is linked to the absence of β2-microglobulin-containing serum molecules
- 1986
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424. ; 83:15, s. 5630-5633
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Tidskriftsartikel (refereegranskat)abstract
- Class I major histocompatibility antigens are composed of a heavy chain that is noncovalently associated with β2-microglobulin (β2m). Most class I molecules are membrane bound, but mouse and rat cDNA clones and genes without a functional code for the transmembrane amino acids have been identified. The membrane-associated class I molecules are important in the control of cell-mediated cytotoxicity, while the function of the soluble molecules remains unclear. Previous studies have shown that β2m circulates in rat serum in three different molecular weight classes. The first is free β2m (M(r), 12,000), the second is about M(r) 70,000, and the third is roughly M(r) 200,000. In an inbred subline of immunodeficient, diabetesprone BioBreeding rats (BioBreeding/Hagedorn), previous work detected two restriction fragment polymorphisms in class I major histocompatibility complex genes, one of them a gene deletion on a 7-kilobase BamHI fragment and the other on a 2-kilobase BamHI fragment. In these rats we have found that the third serum β2m-binding size class is absent. Analysis of F1 and F2 individuals following cross-breeding between Bio-Breeding/Hagedorn rats and genetically related (nondiabetic) control BioBreeding w-subline rats demonstrated that the large-size serum peak of β2m was associated with the presence of the class I restriction fragments.
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| 2. |
- Lind, L, et al.
(författare)
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Long-term treatment with active vitamin D (alphacalcidol) in middle-aged men with impaired glucose tolerance. Effects on insulin secretion and sensitivity, glucose tolerance and blood pressure
- 1989
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Ingår i: Diabetes Research (Edinburgh, Scotland). - 0265-5985. ; 11:3, s. 141-147
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Tidskriftsartikel (refereegranskat)abstract
- There are specific receptors for the active metabolite of vitamin D on the pancreatic beta cells and severe vitamin D deficiency can inhibit insulin secretion. In the present study 14 middle aged men with impaired glucose tolerance and low glucose-stimulated insulin values received 2 micrograms alphacalcidol daily for 18 months. On treatment there was a transient increase of both the peak and the late insulin response to intravenous glucose while neither intravenous nor oral glucose tolerance were consistently altered. Nor was the peripheral insulin sensitivity, measured by the euglycemic clamp technique, significantly affected. In the untreated state there was a positive relationship (r = 0.77) between the tissue insulin sensitivity and the serum concentrations of 25-hydroxyvitamin D. There was also an inverse relationship (r = 0.61) between systolic blood pressure and the serum levels of 1,25-dihydroxy vitamin D. Although the subjects were normotensive and not overweight, treatment with alphacalcidol tended to lower both systolic (6 +/- 12 mmHg) and diastolic blood pressures (5.8 +/- 9.1 mmHg) and there was a small reduction (0.9 kg) in body weight. In conclusion, subjects with impaired glucose tolerance without vitamin D deficiency do not benefit from vitamin D supplementation, which however has some hypotensive action also in normotensive individuals.
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