1,25-dihydroxycholecalciferol regulates rat intestinal calbindin D9k posttranscriptionally

• Published in: The Journal of nutrition Vol. 126; no. 4; pp. 834 - 841
• Main Authors: Duflos, C. (Ecole Pratique des Hautes Etudes, Lyon, France.), Bellaton, C, Baghdassarian, N, Gadoux, M, Pansu, D, Bronner, F
• Format: Journal Article
• Language: English
• Published: Bethesda, MD American Society for Nutritional Sciences 01.04.1996; American Institute of Nutrition
• Subjects: ANIMAL MODELS; Animals; ARN MENSAJERO; ARN MESSAGER; Base Sequence; Biochemistry; Biological and medical sciences; Calbindins; Calcitriol - pharmacology; Calcium; Calcium - administration & dosage; Cecum - metabolism; Colon; Colon - metabolism; DIET; DIETA; DNA Probes; Duodenum - drug effects; Duodenum - metabolism; EXPERIMENTACION; EXPERIMENTATION; Fundamental and applied biological sciences. Psychology; Intestine. Mesentery; Intestines - drug effects; Intestines - metabolism; Kinetics; Male; MESSENGER RNA; MODELE ANIMAL; MODELOS ANIMALES; Molecular Sequence Data; Nucleic Acid Hybridization; Proteins; Rats; Rats, Sprague-Dawley; REGIME ALIMENTAIRE; Ribonucleic acid; RNA; RNA, Messenger - analysis; RNA, Messenger - metabolism; Rodents; S100 Calcium Binding Protein G - genetics; S100 Calcium Binding Protein G - metabolism; Small intestine; TRANSCRIPCION; TRANSCRIPTION; Transcription, Genetic; Vertebrates: digestive system; VITAMIN D; VITAMINA D; VITAMINE D; Binding protein; Vertebrata; Calbindin; Regulation(control); Mammalia; Calcium; Vitamin D; Rat; Cholecalciferol(1,25-dihydroxy); Rodentia; Gene expression; Posttranscriptional modification
• ISSN: 0022-3166; 1541-6100
• DOI: 10.1093/jn/126.4.834

To determine whether calbindin D9k (CaBP) is subject to postranscriptional control, 6-wk-old Sprague Dawley-derived rats were fed one of three purified diets, 1.5% Ca and 3.0% Ca, mostly as carbonate, and 2.9% Ca, mostly as gluconate. Two weeks later, 5-cm segments of duodenum, jejunum, ileum, cecum and colon were obtained and analyzed for CaBP and CaBP-mRNA. Analysis of the steady-state distribution of CaBP-mRNA and of CaBP revealed a statistically-significant (r = 0.95; P 0.01) linear relationship between CaBP-mRNA and CaBP. When, however, animals that had been fed the 1.5% Ca diet received by intrajugular injection 1.2 nmol 1,25-dihydroxycholecalciferol [1,25-(OH)2-D3] and their CaBP-mRNA and CaBP were analyzed as a function of time after 1,25-(OH)2-D3 administration, the kinetic response of the two molecules differed. The CaBP-mRNA increased linearly by approximately 68% for 4 h after administration and then declined over the next 6 h to a concentration below the preinjection value. Thus, appearance and disappearance of CaBP-mRNA approximated 17% h-1. The CaBP, however, increased steeply to 80% above preinjection concentration until 2 h postinjection, i.e., at a rate of 40% h-1. Thereafter, CaBP decreased to 35% above the preinjection value between 5 and 10 h postinjection (2.5% h-1). These findings are consistent with a 1,25-(OH)2-D3-mediated postranscriptional regulation of CaBP concentrations, because the 1,25-(OH)2-D3-mediated increase in CaBP-mRNA is not reflected in an immediately changed CaBP level