Intestinal lead and calcium absorption: effect of 1,25-dihydroxycholecalciferol and lead status

• Published in: Proceedings of the Society for Experimental Biology and Medicine Vol. 194; no. 3; p. 258
• Main Author: Fullmer, C S
• Format: Journal Article
• Language: English
• Published: United States 01.07.1990
• Subjects: Alkaline Phosphatase - biosynthesis; Animals; Body Weight; Calbindins; Calcitriol - administration & dosage; Calcium - blood; Calcium - metabolism; Chickens; Cholecalciferol - deficiency; Diet; Dose-Response Relationship, Drug; Duodenum - metabolism; Intestinal Absorption; Lead - administration & dosage; Lead - metabolism; Male; Phosphorus - blood; S100 Calcium Binding Protein G - biosynthesis; Vitamin D Deficiency - metabolism
• ISSN: 0037-9727
• DOI: 10.3181/00379727-194-43088

This study was designed to investigate, in some detail, the relative effects of the hormonal form of vitamin D (1,25-dihydroxycholecalciferol) on duodenal Pb and Ca absorption as a function of dietary Pb level. When cholecalciferol-deficient chicks were chronically repleted with physiologic levels of 1,25-dihydroxycholecalciferol (1,25(OH)2D3), as the sole source of the vitamin, 203Pb and 47Ca absorption were enhanced over 4- and 8-fold, respectively. Ingestion of Pb during the repletion period had no significant effect on the intestinal Ca absorption response to 1,25-(OH)2D3 even at a very high dietary Pb level. The efficiency of intestinal 203Pb absorption was, however, significantly diminished by dietary Pb, in an apparent dose-dependent fashion. The results indicate that the extent to which systemic Ca homeostatic mechanisms influence intestinal Pb absorption is dependent, in large part, on Pb status.