How Dietary Deficiency Studies Have Illuminated the Many Roles of Vitamin A During Development and Postnatal Life

Vitamin A deficiency studies have been carried out since the early 1900s. Initially, these studies led to the identification of fat soluble A as a unique and essential component of the diet of rodents, birds, and humans. Continuing work established that vitamin A deficiency produces biochemical and physiological dysfunction in almost every vertebrate organ system from conception to death. This chapter begins with a review of representative historical and current studies that used the nutritional vitamin A deficiency research model to gain an understanding of the many roles vitamin A plays in prenatal and postnatal development and well-being. This is followed by a discussion of recent studies that show specific effects of vitamin A deficiency on prenatal development and postnatal maintenance of the olfactory epithelium, brain, and heart. Vitamin A deficiency studies have helped define the necessity of vitamin A for the health of all vertebrates, including farm animals, but the breadth of deficient states and their individual effects on health have not been fully determined. Future work is needed to develop tools to assess the complete vitamin A status of an organism and to define the levels of vitamin A that optimally support molecular and systems level processes during all ages and stages of life

The life history traits and population dynamics of the brooding bivalve, Transennella tantilla (Gould) in the South Slough of Coos Bay, Oregon

ix, 73 leaves : ill. ; 28 cm Typescript Thesis (M.S.)--University of Oregon Includes vita and abstract Bibliography: leaves 71-73 Another copy on microfilm is located in Archives University of Oregon theses, Dept. of Biology, M.S., 198

Retinoic Acid Is Present in the Postnatal Rat Olfactory Organ and Persists in Vitamin A–Depleted Neural Tissue1–3

Vitamin A (VA), all-trans-retinol (at-ROL), and its derivative, all-trans-retinoic acid (at-RA), are required for neuron development. The effects of these retinoids are dependent upon the nutritional status of the rat and tissue-specific dynamics of retinoid access and utilization. The purpose of this study was to determine the status of at-ROL and at-RA in the peripheral olfactory organ of postnatal rats fed a normal diet and rats fed a VA-deficient (VAD) diet. Extracted retinoids were analyzed by HPLC. Resolved sample peaks were identified by comparing their elution times and spectra with those of authentic standards. Mean at-RA and at-ROL concentrations of 23 pmol/g olfactory tissue and 0.13 nmol/g, respectively, were recovered from olfactory tissue. The ratio of at-RA:at-ROL in olfactory was ∼2 times that in testis and 200 times that in liver. at-ROL was depleted from the liver and olfactory organ of rats fed a VAD diet from birth to 70 d of age. Surprisingly, at-RA was still present in olfactory tissue from these rats. At 90 d of age, the VAD rats were frankly deficient and at-RA was no longer detectable in olfactory tissue. The comparatively high ratio of at-RA:at-ROL in the peripheral olfactory organ and the persistence of at-RA in at-ROL-depleted tissues strongly suggests that maintenance of local stores of at-RA is functionally relevant in this tissue

Detection of variable levels of RARalpha and RARgamma proteins in pluripotent and differentiating mouse embryonal carcinoma and mouse embryonic stem cells

Pluripotent mouse embryonal carcinoma (mEC) and mouse embryonic stem (mES) cells differentiate into several cell lineages upon retinoic acid (RA) addition. Differentiation is facilitated, in part, by RA activation of nuclear RA receptors (RARs) that bind to DNA response elements located in the promoters of target genes. The purpose of the studies reported here was to immunolocalize RARalpha and RARgamma protein in mEC and mES cells and in their RA-induced differentiated progeny. Fixed cells were reacted with three different RARalpha antibodies and one RARgamma antibody. Pluripotent and differentiated mEC and mES cells showed positive nuclear immunoreactivity with all antibodies tested. Two RARalpha antibodies also showed positive reactivity in the cytoplasm. Surprisingly, our results revealed variability in immunofluorescence intensity and in RARalpha and RARgamma distribution from one cell to the other, suggesting that RARalpha and RARgamma protein levels were not synchronous throughout the cell population. The results indicate that RARalpha and RARgamma are present in pluripotent and differentiating mEC and mES cells and suggest that the expression of these proteins is dynamic

Loss of vitamin A stores impairs cardiac workload and function under stress conditions

Study Objectives: Assess cardiac function under baseline and cardiac stress conditions in mice with and without hepatic vitamin A stores