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Activity of ornithine decarboxylase and creatine kinase in soft and hard tissue of vitamin D‐deficient chicks following parenteral application of 1,25‐dihydroxyvitamin D 3 or 24R,25‐dihydroxyvitamin D 3
Author(s) -
Ittel Thomas H.,
Ross F. P.,
Norman Anthony W.
Publication year - 1986
Publication title -
journal of bone and mineral research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.882
H-Index - 241
eISSN - 1523-4681
pISSN - 0884-0431
DOI - 10.1002/jbmr.5650010106
Subject(s) - ornithine decarboxylase , endocrinology , medicine , vitamin , duodenum , stimulation , kidney , creatine kinase , calcitriol , vitamin d and neurology , chemistry , biology , enzyme , biochemistry
We investigated the stimulation of creatine kinase (CK) and ornithine decarboxylase (ODC) by 1,25‐dihydroxyvitamin D 3 [1,25(OH) 2 D 3 ] and 24R,25‐dihydroxyvitamin D 3 [24R,25(OH) 2 D 3 ] in doses ranging from 1.625 to 6500 pmol in 4‐week‐old vitamin D‐deficient chicks. Enzyme activities were monitored for 72 h. 1,25(OH) 2 D 3 but not 24R,25(OH) 2 D 3 enhanced the activity of ODC in duodenum and bone. The time course of ODC activity in bone was biphasic, with an increase after 1 h and a higher peak after 24 h. Diaphyses and epiphyses responded equally well after a dose of 6500 pmol. The kidney, liver, and lung showed 1.5–3.8‐fold increase in CK activity following 1,25(OH) 2 D 3 , reaching a maximum between 3–5 h. However, sustained stimulation of CK activity could still be demonstrated after 72 h, and the 48‐h levels in the lung even exceeded the 5‐h values. No change of activity of either enzyme was noted in heart and brain after application of 1,25(OH) 2 D 3 . There was no coincidence of stimulation of ODC and CK by 1,25(OH) 2 D 3 in the same tissue, and the dose‐responsiveness of both enzymes differed considerably. Near maximum activities of ODC were achieved with 19.5 pmol 1,25(OH) 2 D 3 in duodenum and pancreas, while maximum responses of CK occurred in the liver at 195 pmol and in lung and kidney at 6500 pmol. 24R,25(OH) 2 D 3 failed to produce any consistent effects of either enzyme in all tissues examined. These results, particularly the lack of response to 24R,25(OH) 2 D 3 , are different from those reported in rats.