A series of four experiments was undertaken to determine both the quantitative and qualitative effects of magnesium deprivation on the urinary glycoproteins of adult and grow.ing rats. The glycoproteins were to be isolated in 0.58 M Na.Cl, the isolation technique for Tamm-Horsfall glycoprotein. Quantitative excretion was measured as ɣ hexose/rat/day. Qualitative analyses were reported as percent of dry weight of material isolated. A glycoprotein-containing material precipitated spontaneously from the urine before addition of NaCl. The dry weight ratio of spontaneously precipitating material (Fraction I) to salt-precipitable material (Fraction II) was 16 to one in normal animals, 3.4 to one in depleted animals. The hexose to amino acid to uronic acids ratio was the same for both fractions in both groups. No hexosamines were found in either fraction. The ash content was lower in Fraction I for deficient animals, but higher in Fraction II for deficient animals, when compared to control animals. Increased phosphate binding by Fraction II from deficient animals was indicated. A slight rise in total glycoprotein excreted daily was shown in animals fed a magnesium deficient diet, but not until after the first week, when irreversible kidney damage is initiated. Control animals whose weight ga:m was restricted to 32% 0£ normal excreted less of Fraction I per day. Amino acid patterns of both fractions from all groups were similar, but differed from those reported for human and sheep Tamm-Horsfall glycoprotein. All depleted animals showed a significant (p> 0.01} increase in kidney calcium content, and one group showed a significant (p> 0.01) decrease in kidney magnesium content at five weeks. / M.S.

Feeding growing rats a diet deficient in magnesium results in a deficiency condition whose major characteristic, that of kidney calcification, exhibits a mechanism very similar to that of urolithiasis in humans. Work done with lysosomal stabilizers and rats fed this deficient diet shows a reduction in calcification with the administration of these drugs. Accordingly, a study was undertaken to examine the mechanism of this process more closely with regards to a possible involvement of kidney lysosomes or the vacuolar apparatus. Lysosomal enzyme levels in the kidneys of rats fed either a low magnesium or a control diet were examined and an attempt made to determine if there were any differences due to treatments. While biochemical evidence suggests no differences, histochemically we see what appears to be a shift in activity to the area where calcification occurs. At the same time, while there is no effect from treatment, there appears to be a time effect, enzyme activity decreasing or increasing significantly with day. This seems to appear histochemically in the form of increased PAS sustainability in sections from rats on either low magnesium or control diet compared to rats on a rat pellet diet. / Master of Science

Thesis (Ph. D.)--University of Missouri-Columbia, 2001. / Typescript. Vita. Includes bibliographical references. Also available on the Internet.

Thesis (Ph. D.)--University of Missouri-Columbia, 2001. / Typescript. Vita. Includes bibliographical references. Also available on the Internet.