Lysosomal proliferation in rachitic avian intestinal absorptive cells following 1,25-dihydroxycholecalciferol.
Lysosomes in chick intestinal absorptive cells from rachitic (vitamin D-deficient) and vitamin D-replete animals were studied utilizing transmission electron microscopic histochemistry and ultrastructural morphometry. Absorptive cells from rachitic animals, serum calcium = 7.3 +/- 0.3 mg%, contained an average of 4.0 +/- 0.3 supranuclear lysosomes. In rachitic chicks sacrificed 9 hr post-injection of 1,25-dihydroxycholecalciferol, the active metabolite of vitamin D, the values for both serum calcium, 9.8 +/- 0.2 mg%, and the number of apical absorptive cell lysosomes, 12.9 +/- 0.6, were increased over non-injected or vehicle-only injected animals. Lysosomes in vitamin D-replete absorptive cells were characterized by their intense staining with pyroantimonate, indicative of their high calcium content. The same organelles also produced a positive reaction for acid phosphatase. Rachitic lysosomes, also acid phosphatase positive, were only lightly stained with pyroantimonate. The lysosomal proliferation apparently induced by 1,25-dihydroxycholecalciferol may be a further indication that these organelles play a role in intestinal calcium transport and/or intracellular calcium homeostasis within the absorptive cell.
D000135:Acid Phosphatase / Q000378:metabolism; D000818:Animals; D002117:Calcitriol / Q000494:pharmacology*; D002118:Calcium / Q000097:blood; D002645:Chickens; D007413:Intestinal Mucosa / Q000648:ultrastructure*; D008247:Lysosomes / Q000201:enzymology / Q000648:ultrastructure*; D008297:Male; D008854:Microscopy, Electron; D012279:Rickets / Q000473:pathology*
D000135:Acid Phosphatase; D002117:Calcitriol; D002118:Calcium