- Home
- A-Z Publications
- Annual Review of Nutrition
- Previous Issues
- Volume 15, 1995
Annual Review of Nutrition - Volume 15, 1995
Volume 15, 1995
- Preface
-
- Review Articles
-
-
-
The Evolution of National Nutrition Policy
Vol. 15 (1995), pp. xiii–xxviMore LessDomestic regulatory efforts in the area of nutrition historically have focused on achieving and sustaining the highest possible level of food safety and availability. More recently, the linkages between certain dietary practices and the risk of chronic, degenerative diseases have also become a significant focus of public policy.
In order to promote good nutrition practices, the Food and Drug Administration (FDA) now requires a detailed and informative Nutrition Facts food label on virtually all food packages. Other public policies promoted by the FDA and others include increasing public knowledge of the relationship between diet and health; promoting unified food and nutrition policies among all government agencies; educating the American consumer about sound dietary practices; and encouraging the development of technologies that may result in more healthful, more abundant, and more affordable foods.
-
-
-
-
Role of Vitamin K in Bone Metabolism
Vol. 15 (1995), pp. 1–21More LessVitamin K is a cofactor required for the formation of γ-carboxyglutamate (Gla) residues in proteins. Osteoblasts produce at least three different Gla-containing proteins: osteocalcin, matrix Gla-protein, and protein S. After cellular secretion of these proteins, the main part of each remains bound to the hydroxyapatite matrix in bone, but their function remains unclear. Part of the newly synthesized osteocalcin is also set free into the bloodstream, where it may be used as a diagnostic marker for bone formation. Several studies have demonstrated that a poor vitamin K status is associated with an increased risk of osteoporotic bone fractures. Whether vitamin K supplementation will reduce the rate of bone loss in postmenopausal women remains a matter of debate.
-
-
-
Regulation of Tight-Junction Permeability During Nutrient Absorption Across the Intestinal Epithelium
Vol. 15 (1995), pp. 35–55More LessTight junctions are located at the luminal aspect of adjacent epithelial cells and form a barrier that limits the paracellular diffusion of hydrophilic solutes. In recent years, evidence has accumulated to indicate that tight-junction permeability is regulated by the absorption of various nutrients. In this review, we present the physiological basis and importance of tight-junction regulation in intestinal epithelium. The molecular structure of tight junctions and their interactions with the cell cytoskeleton as well as the physical and chemical forces that influence tight junction permeability are described. Much of this review addresses the controversial Pappenheimer hypothesis, which states that a major portion of intestinal glucose absorption occurs through tight junctions and not by saturable transcellular active transport. The absorption of a significant portion of glucose through tight junctions requires increased junctional permeability, a very high intralumenal glucose concentration, and a sufficient osmotic gradient to promote volume flow.
-
-
-
Whole-Body Protein Turnover in Humans—Past, Present, and Future
Vol. 15 (1995), pp. 57–92More LessProtein turnover is a fundamental biological process in all living organisms. The study of protein turnover in human subjects, and in the body as a whole, is of relatively recent origin. In this review, I summarize briefly how this field of work has expanded over the past 25 years, with emphasis on conceptual problems and controversies, particularly those related to methods of measurement. We cannot be certain that our estimates are accurate because no method of verification exists, but progress will be made through successive approximations. Some of the applications are described in different physiological and pathological states such as growth and trauma, and possible directions for fruitful future research are indicated.
-
-
-
Lactoferrin: Molecular Structure and Biological Function
B. Lönnerdal, and S. IyerVol. 15 (1995), pp. 93–110More LessLactoferrin is an 80-kDa, iron-binding glycoprotein present in milk and, to a lesser extent, in exocrine fluids such as bile and tears. It consists of a single-chain polypeptide with two gobular lobes and is relatively resistant to proteolysis. The complete cDNAs for lactoferrin from human milk, neutrophils, and bovine milk have been reported, and recombinant proteins have been produced. Owing to its iron-binding properties, lactoferrin has been proposed to play a role in iron uptake by the intestinal mucosa and to act as a bacteriostatic agent by withholding iron from iron-requiring bacteria. Its presence in neutrophils and its release during inflammation suggest that lactoferrin is also involved in phagocytic killing and immune responses. Additionally, lactoferrin may function in ways not related to iron-binding, e.g. as a growth factor and as a bactericidal agent. This review attempts to evaluate these proposed functions and their biological significance in more detail.
-
-
-
Retinoids as Teratogens
Vol. 15 (1995), pp. 111–132More LessVitamin A is a necessary nutrient in the diet. However, excessive doses of retinoids by pregnant women result in teratogenesis. In this chapter, we initially discuss the occurrence and characteristics of fetal malformations associated with maternal ingestion of natural and synthetic retinoids in both experimental animals and humans. We then tum to an examination of the pharmacology of teratogenic retinoids, focusing on structure-function relationships and pharmacokinetics. Finally, we review the current literature on the molecular mechanism of action of teratogenic doses of retinoids and the role of the retinoic acid receptors and other target genes in this process.
-
-
-
Regulation of Glutaminase Activity and Glutamine Metabolism
Vol. 15 (1995), pp. 133–159More LessGlutamine is synthesized primarily in skeletal muscle, lungs, and adipose tissue. Plasma glutamine plays an important role as a carrier of nitrogen, carbon, and energy between organs and is used for hepatic urea synthesis, for renal ammoniagenesis, for gluconeogenesis in both liver and kidney, and as a major respiratory fuel for many cells. The catabolism of glutamine is initiated by either of two isoforms of the mitochondrial glutaminase. Liver-type glutaminase is expressed only in periportal hepatocytes of the postnatal liver, where it effectively couples ammonia production with urea synthesis. Kidneytype glutaminase is abundant in kidney, brain, intestine, fetal liver, lymphocytes, and transformed cells, where the resulting ammonia is released without further metabolism. The two isoenzymes have different structural and kinetic properties that contribute to their function and short-term regulation. Although there is a high degree of identity in amino acid sequences, the two glutaminases are the products of different but related genes. The two isoenzymes are also subject to long-term regulation. Hepatic glutaminase is increased during starvation, diabetes, and feeding a high-protein diet, whereas kidney-type glutaminase is increased only in kidney in response to metabolic acidosis. The adaptations in hepatic glutaminase are mediated by changes in the rate of transcription, whereas kidney-type glutaminase is regulated at a posttranscriptional level.
-
-
-
Roles of Ubiquitinylation in Proteolysis and Cellular Regulation
Vol. 15 (1995), pp. 161–189More LessMost eukaryotic organisms respond to starvation, nutrient deprivation, and/or stress by increasing the rates of intracellular proteolysis. The amino acids released may be reutilized for synthesis of important proteins, or directly for the production of energy. This enhanced proteolysis is also required for repair of cellular damage due to environmental insults such as heat shock, free radicals, viral infection, or mutation. Finally, intracellular proteolysis is important in determining the steady-state levels of a wide variety of regulatory proteins, particularly those regulating the cell cycle. The ubiquitin-dependent proteolytic system participates in all of these functions. In spite of its cytoplasmic localization, this system is selective and acts only on a limited set of substrates. This review discusses the mechanisms of this selectivity and the potential roles of ubiquitin-dependent proteolysis.
-
-
-
Energy Partitioning and Modeling in Animal Nutrition
R. L. Baldwin, and R. D. SainzVol. 15 (1995), pp. 191–211More LessWe first present a brief discussion of early and current models (feeding systems) used to estimate animal energy and protein requirements and to predict performance based on feed composition and intake. We then touch on some limitations inherent in these systems. Next, we propose that dynamic (i.e. time-variant) models and mechanistic models (i.e. equations based on knowledge of physiological functions) are superior to earlier systems for both practical and research applications. Finally, we describe a number of applied and research models of animal growth and lactation to illustrate how biological concepts may be represented in equation form. Equations that represent current knowledge of underlying functions can be used to improve predictions of animal requirements and performance and to evaluate hypotheses about nutritional and physiological mechanisms that influence animal performance.
-
-
-
Regulation of Pigeon Cropmilk Secretion and Parental Behaviors by Prolactin
Vol. 15 (1995), pp. 213–238More LessProlactin stimulates the growth and development of specialized epithelial cells lining the cropsac of pigeons and doves (family Columbidae), leading to formation of “cropmilk,” which is fed to the newly hatched squab. This system of milk feeding is unique among birds. To support the feeding of cropmilk, a complex array of behavioral adaptations are also supported by high levels of prolactin secretion in columbids during parenting. These specializations include elevated food intake (hyperphagia), nest attendance, and regurgitation feeding of the squab. Although prolactin is clearly important for these behavioral adaptations, the precise physiological and mechanistic bases for these behavioral effects remain controversial. The molecular mechanisms of prolactin action in the cropsac epithelium have been studied by cloning prolactin-induced genes, by cloning and expressing the pigeon prolactin receptor, and by analyzing the transcription factors that are activated after prolactin treatment. The avian (pigeon) prolactin receptor is a member of the cytokine receptor superfamily and uniquely contains a complete duplication of the extracellular ligand-binding domain. One of the early signaltransducing actions of prolactin in cropsac epithelium is the activation of signal transducer and activator of transcription (STAT) proteins via tyrosine phosphorylation. This fundamental signaling pathway is shared with mammalian prolactin target tissues. The convergent evolution of milk feeding and the behaviors that support parenting in columbids and mammals has depended on adaptation of both conserved mechanisms and divergent physiological processes.
-
-
-
Nutritional and Hormonal Regulation of Thyroid Hormone Deiodinases
P. R. Larsen, and M. J. BerryVol. 15 (1995), pp. 323–352More LessSelenocysteine has been identified in the active center of types 1 and 3 iodothyronine deiodinases, two important enzymes regulating the formation and degradation of the active thyroid hormone, 3,5,3′-triiodothyronine (T3). Selenium is thus required for such complex processes as normal growth, brain development, and metamorphosis, all of which are thyroid hormone dependent. Structural and functional analyses of the type 1 deiodinase mRNA allowed identification of the selenocysteine insertion sequence (SECIS) element, a stem-loop structure in the 3′ untranslated region of the mRNA. SECIS elements with conserved sequence and structural features are also present in the 3′ untranslated regions of the mRNAs encoding selenoprotein P and the glutathione peroxidase family of selenoproteins. These elements are necessary and sufficient for directing selenocysteine incorporation into the deiodinases and the other mammalian selenoproteins.
-
Previous Volumes
-
Volume 44 (2024)
-
Volume 43 (2023)
-
Volume 42 (2022)
-
Volume 41 (2021)
-
Volume 40 (2020)
-
Volume 39 (2019)
-
Volume 38 (2018)
-
Volume 37 (2017)
-
Volume 36 (2016)
-
Volume 35 (2015)
-
Volume 34 (2014)
-
Volume 33 (2013)
-
Volume 32 (2012)
-
Volume 31 (2011)
-
Volume 30 (2010)
-
Volume 29 (2009)
-
Volume 28 (2008)
-
Volume 27 (2007)
-
Volume 26 (2006)
-
Volume 25 (2005)
-
Volume 24 (2004)
-
Volume 23 (2003)
-
Volume 22 (2002)
-
Volume 21 (2001)
-
Volume 20 (2000)
-
Volume 19 (1999)
-
Volume 18 (1998)
-
Volume 17 (1997)
-
Volume 16 (1996)
-
Volume 15 (1995)
-
Volume 14 (1994)
-
Volume 13 (1993)
-
Volume 12 (1992)
-
Volume 11 (1991)
-
Volume 10 (1990)
-
Volume 9 (1989)
-
Volume 8 (1988)
-
Volume 7 (1987)
-
Volume 6 (1986)
-
Volume 5 (1985)
-
Volume 4 (1984)
-
Volume 3 (1983)
-
Volume 2 (1982)
-
Volume 1 (1981)
-
Volume 0 (1932)