Biomaterial Database

Regulation and its refractoriness of 25-hydroxyvitamin D3 metabolism in vitamin D deficiency. 1981

N Takahashi, and C Miyaura, and N Horiuchi, and T Suda

The time course of change in plasma calcium levels and renal metabolism of 25-hydroxyvitamin D3 [25(OH)D3] was investigated in chicks maintained on a vitamin D-deficient diet for 4 weeks. Plasma calcium concentrations dropped sharply between the 7th and 14th day of the feeding period. Renal 25(OH)D3-1 alpha-hydroxylase activity was reciprocally enhanced concurrently with the decrease in plasma calcium levels. The elevated activity of 1 alpha-hydroxylase had declined significantly by the 21st and 28th days in spite of the more severe hypocalcemia. When graded amounts of vitamin D3 were administered to the chicks maintained on this diet for 14 or 28 days, there were considerable differences in the change of plasma calcium levels and 25(OH)D3 metabolism induced by vitamin D3 administration between the 14-day and 28-day birds. The minimal dose levels of vitamin D3 to completely suppress renal 1 alpha-hydroxylase activity were 25 micrograms in the 14-day, and 2.5 mg in the 28-day birds. These differences were not observed between the 14-day and 28-day birds when 1 alpha-hydroxyvitamin D3 [1 alpha(OH)D3] was administered. Renal adenylate cyclase activity induced by parathyroid hormone (PTH) was much lower in the 28-day chicks than that in 1-day-old and the 14-day birds. These results are explained by the hypersecretion of PTH and the subsequent refractoriness of the target organs in severe vitamin D deficiency. Plasma calcium levels per se did not appear to be a major factor in the regulation of 25(OH)D3 metabolism.

UI	MeSH Term	Description	Entries
D006961	Hyperparathyroidism	A condition of abnormally elevated output of PARATHYROID HORMONE (or PTH) triggering responses that increase blood CALCIUM. It is characterized by HYPERCALCEMIA and BONE RESORPTION, eventually leading to bone diseases. PRIMARY HYPERPARATHYROIDISM is caused by parathyroid HYPERPLASIA or PARATHYROID NEOPLASMS. SECONDARY HYPERPARATHYROIDISM is increased PTH secretion in response to HYPOCALCEMIA, usually caused by chronic KIDNEY DISEASES.
D007668	Kidney	Body organ that filters blood for the secretion of URINE and that regulates ion concentrations.	Kidneys
D008297	Male		Males
D010281	Parathyroid Hormone	A polypeptide hormone (84 amino acid residues) secreted by the PARATHYROID GLANDS which performs the essential role of maintaining intracellular CALCIUM levels in the body. Parathyroid hormone increases intracellular calcium by promoting the release of CALCIUM from BONE, increases the intestinal absorption of calcium, increases the renal tubular reabsorption of calcium, and increases the renal excretion of phosphates.	Natpara,PTH (1-84),PTH(1-34),Parathormone,Parathyrin,Parathyroid Hormone (1-34),Parathyroid Hormone (1-84),Parathyroid Hormone Peptide (1-34),Hormone, Parathyroid
D002112	Calcifediol	The major circulating metabolite of VITAMIN D3. It is produced in the LIVER and is the best indicator of the body's vitamin D stores. It is effective in the treatment of RICKETS and OSTEOMALACIA, both in azotemic and non-azotemic patients. Calcifediol also has mineralizing properties.	25-Hydroxycholecalciferol,25-Hydroxyvitamin D 3,25-Hydroxycholecalciferol Monohydrate,25-Hydroxyvitamin D3,Calcidiol,Calcifediol Anhydrous,Calcifediol, (3 alpha,5Z,7E)-Isomer,Calcifediol, (3 beta,5E,7E)-Isomer,Calderol,Dedrogyl,Hidroferol,25 Hydroxycholecalciferol,25 Hydroxycholecalciferol Monohydrate,25 Hydroxyvitamin D 3,25 Hydroxyvitamin D3,Anhydrous, Calcifediol,Monohydrate, 25-Hydroxycholecalciferol
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
D002645	Chickens	Common name for the species Gallus gallus, the domestic fowl, in the family Phasianidae, order GALLIFORMES. It is descended from the red jungle fowl of SOUTHEAST ASIA.	Gallus gallus,Gallus domesticus,Gallus gallus domesticus,Chicken
D006887	Hydroxycholecalciferols	Hydroxy analogs of vitamin D 3; (CHOLECALCIFEROL); including CALCIFEDIOL; CALCITRIOL; and 24,25-DIHYDROXYVITAMIN D 3.	Hydroxyvitamins D,Hydroxycholecalciferol
D000262	Adenylyl Cyclases	Enzymes of the lyase class that catalyze the formation of CYCLIC AMP and pyrophosphate from ATP.	Adenyl Cyclase,Adenylate Cyclase,3',5'-cyclic AMP Synthetase,Adenylyl Cyclase,3',5' cyclic AMP Synthetase,AMP Synthetase, 3',5'-cyclic,Cyclase, Adenyl,Cyclase, Adenylate,Cyclase, Adenylyl,Cyclases, Adenylyl,Synthetase, 3',5'-cyclic AMP
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia