Biomaterial Database

Intestinal calcium absorption: a vitamin D-hormone-mediated adaptive response. 1990

A W Norman

Division of Biomedical Sciences, University of California, Riverside 92521.

The process of intestinal calcium absorption represents the mechanism for dietary calcium to enter into the physiological processes that contribute both to the skeletal growth of the organism and to the maintenance of calcium homeostasis (both intracellular and extracellular). Because there is a large variation worldwide in the availability of dietary calcium (300-1500 g/d for man) and because there is a changing physiological need throughout life (growth, puberty, pregnancy, lactation, and menopause) for absorption of 50-500 mg/d of dietary calcium, it is essential that the process of intestinal calcium absorption be adaptable and responsive to both the dietary and physiological circumstances. This article reviews the evidence that this adaptation process is largely orchestrated by the vitamin D endocrine system. In this model the steroid hormone 1,25-dihydroxycholecalciferol has been shown to stimulate intestinal calcium absorption by both genomic (receptor mediated) and nongenomic (transcaltachia mediated) mechanisms.

UI	MeSH Term	Description	Entries
D007408	Intestinal Absorption	Uptake of substances through the lining of the INTESTINES.	Absorption, Intestinal
D002118	Calcium	A basic element found in nearly all tissues. It is a member of the alkaline earth family of metals with the atomic symbol Ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes.	Coagulation Factor IV,Factor IV,Blood Coagulation Factor IV,Calcium-40,Calcium 40,Factor IV, Coagulation
D006728	Hormones	Chemical substances having a specific regulatory effect on the activity of a certain organ or organs. The term was originally applied to substances secreted by various ENDOCRINE GLANDS and transported in the bloodstream to the target organs. It is sometimes extended to include those substances that are not produced by the endocrine glands but that have similar effects.	Hormone,Hormone Receptor Agonists,Agonists, Hormone Receptor,Receptor Agonists, Hormone
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000222	Adaptation, Physiological	The non-genetic biological changes of an organism in response to challenges in its ENVIRONMENT.	Adaptation, Physiologic,Adaptations, Physiologic,Adaptations, Physiological,Adaptive Plasticity,Phenotypic Plasticity,Physiological Adaptation,Physiologic Adaptation,Physiologic Adaptations,Physiological Adaptations,Plasticity, Adaptive,Plasticity, Phenotypic
D000328	Adult	A person having attained full growth or maturity. Adults are of 19 through 44 years of age. For a person between 19 and 24 years of age, YOUNG ADULT is available.	Adults
D001692	Biological Transport	The movement of materials (including biochemical substances and drugs) through a biological system at the cellular level. The transport can be across cell membranes and epithelial layers. It also can occur within intracellular compartments and extracellular compartments.	Transport, Biological,Biologic Transport,Transport, Biologic
D014807	Vitamin D	A vitamin that includes both CHOLECALCIFEROLS and ERGOCALCIFEROLS, which have the common effect of preventing or curing RICKETS in animals. It can also be viewed as a hormone since it can be formed in SKIN by action of ULTRAVIOLET RAYS upon the precursors, 7-dehydrocholesterol and ERGOSTEROL, and acts on VITAMIN D RECEPTORS to regulate CALCIUM in opposition to PARATHYROID HORMONE.