Involvement of Cellular Retinoic Acid (CRABP) or Retinol (CRBP) Binding Proteins and 1,25-dihydroxyvitamin D₃ (1,25(OH)₂D₃) receptors in the response of cultured cells to retinoic acid and 1,25(OH)₂D₃ was examined. A new method for saturation analysis of CRABP and CRBP was applied to human tumors, human neuroblastoma cells, which retinoic acid causes to differentiate, and a bioselected subline resistant to retinoic acid. These data suggest that CRABP may not mediate cell differentiation by retinoic acid. In other studies, 1,25(OH)₂D₃ receptors and bioresponses were characterized in cultured primate cells. Rhesus monkey kidney cells (LLC-MK₂) were resistant to 1,25(OH)₂D₃-dependent induction of 25(OH)D-24-hydroxylase enzyme. The ED₅₀ in LLC-MK₂ cells was 10-100 fold higher than in other cultured cells. This resistance resulted from a low affinity receptor. Since the LLC-MK₂ variant receptor did not differ in size from the wild type rhesus 1,25(OH)₂D₃ receptor, (Mᵣ = 52 kDa) a subtle alteration in the receptor likely caused the decreased ligand affinity. Also of interest was the possible cellular resistance to 1,25(OH)₂D₃, in the owl monkey (Aotus trivurgatus), which generally occurs in new world primates. Owl monkey kidney (OMK) cells had the same content of receptors for 1,25(OH)₂D₃ and sensitivity to this hormone as cells from the rhesus monkey (old world primate). The ED₅₀ for induction of 24hydroxylase was 2-3 nM in both the OMK cells and the rhesus monkey fibroblasts. Both cells contained 2300 high affinity receptor molecules per cell, which bound DNA and were characterized by immunoblot as 52 kDa proteins. 1,25(OH)₂D₃ treatment increased the content of 1,25(OH)₂D₃ receptors in OMK cells, by increasing the synthesis of receptor mRNA. These data indicate the owl monkey is not resistant to 1,25(OH)₂D₃, unlike other new world primates. This finding was confirmed independently by demonstration that the owl monkey maintained mean serum 1,25(OH)₂D₃ levels (29 pg/ml) in the range of old world primates (33 pg/ml) and humans, in contrast to the elevated 1,25(OH)₂D₃ in other new world primates (97-129 pg/ml). This result suggests the alteration of 1,25(OH)₂D₃-endocrine dynamics in new world primates occurred subsequent to the evolutionary divergence of the owl monkey.

The relative enrichment of skin sebaceous gland lipids with deuterium-labeled α-tocopherol was compared with plasma enrichment to evaluate the delivery of vitamin E to skin. For the first week of this study, each subject consumed a daily dose of deuterated vitamin E (150 mg of an equimolar mixture of RRR-α-[5-(C²H₃)]-(d₃) and all rac-α-[5,7-(C²H₃)₂]-(d₆) tocopheryl acetates) with breakfast. Blood was drawn and skin lipids were collected daily for two weeks, then every other day for the following two weeks. Labeled and unlabeled vitamin E analysis was carried out using liquid chromatography and mass spectrometry (LC/MS). Skin cholesterol, plasma cholesterol and triglycerides were measured to evaluate changes in vitamin E levels relative to lipid content. While d₃ and d₆-α-tocopherols were found in plasma 24 h after the first dose, d₃-α-tocopherol was only detected in the skin sebaceous gland secretions after 1 week of supplementation. This data suggests a skin-mediated delivery system for vitamin E into skin lipid secretions. This finding is also supported by the observation that the ratio of α-to γ-tocopherol was greater in the skin than in the plasma. / Graduation date: 2002

The roles of vitamin C and the effects of supplementation have been under investigation for many years. The purpose of this study was to use high performance liquid chromatography to assess the presence of vitamin C in human sweat, to evaluate sweat as a possible excretory route for vitamin C and to note any effects of vitamin C supplementation. Vitamin C in sweat was determined in samples from 10 active men and women prior to supplementation and weekly for 4 consecutive weeks as the vitamin C supplements were with a reverse-phase liquid chromatograph (Model ALC-202) equipped with a solvent delivery system (Model 6000, Waters Association).The presence of vitamin C in sweat samples was indicated by comparing peaks to those seen with vitamin C observed in sweat samples. Vitamin C was observed in sweat at the end of the first week of supplementation. The pres C.However, 4 and 5 when standards. During the first week of the study, when subjects' diets were not supplemented, vitamin C was not observed in sweat samples. Vitamin C was observed in sweat at the end of the first week o supplementation. The presence of vitamin C in sweat diminished during weeks 4 and 5 when intakes were supplemented with 750 mg and 1000 mg, respectively. It appeared that supplementation affected the presence of vitamin C in human sweat until plasma or tissues were saturated, at which point absorption may have decreased and other means of excretion may have been enhanced.

No description available.

published_or_final_version / Medical Sciences / Master / Master of Medical Sciences

No description available.

No description available.

Graduation date: 1944

Thesis (Ph. D.)--University of Wisconsin--Madison, 1980. / Typescript. Vita. Includes bibliographical references.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1954. / Typescript. Includes reprints from The Journal of Biological Chemistry and from The Journal of Nutrition. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 59-60).