Kinetics of mRNA expression of alkaline phosphatase isoenzymes in hepatic tissues from glucocorticoid-treated dogs.
OBJECTIVE
To clone segments of the canine liver alkaline phosphatase (LALP) and corticosteroid-induced alkaline phosphatase (CIALP) genes and use those clones to determine the tissue source of CIALP, the kinetics of LALP and CIALP mRNA expression for glucocorticoid-treated dogs, and the correlation between LALP and CIALP transcript concentrations and isoenzyme activities.


METHODS
Tissues obtained from 7 dogs treated with prednisone (1 mg/kg, SC, q 24 h) for up to 32 days and 1 untreated (control) dog.


METHODS
Gene segments of LALP and CIALP were obtained by reverse transcription-polymerase chain reaction (RT-PCR) assay. The tissue source of CIALP and IALP mRNA was determined by northern blot analysis of tissues from 1 of the glucocorticoid-treated dogs. Hepatic tissues and serum samples were obtained from the 6 remaining glucocorticoid-treated dogs on days 0, 2, 5, 10, and 32 of prednisone treatment, and relative expression of LALP and CIALP mRNA was correlated with LALP and CIALP activity.


RESULTS
A 2,246-base pair (bp) segment of canine LALP and a 1,338-bp segment of CIALP were cloned. Northern blot analysis revealed CIALP mRNA expression in hepatic tissues only after glucocorticoid treatment. Kinetics of LALP and CIALP mRNA expression in the liver of glucocorticoid-treated dogs paralleled liver and serum activities of LALP and CIALP.


CONCLUSIONS
The liver is the most likely source for CIALP in dogs. Analysis of kinetics of serum and hepatic LALP and CIALP mRNA suggests that after glucocorticoid treatment, both are regulated by modification of mRNA transcript concentrations, possibly through differing mechanisms.
Wiedmeyer
Charles E
CE
Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Illinois, Urbana 61802, USA.
Solter
Philip E
PE
Hoffmann
Walter E
WE
D000469:Alkaline Phosphatase / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001706:Biopsy / Q000662:veterinary; D015152:Blotting, Northern / Q000662:veterinary; D003001:Cloning, Molecular; D004285:Dogs / Q000378:metabolism*; D004790:Enzyme Induction / Q000187:drug effects; D005938:Glucocorticoids / Q000494:pharmacology*; D007413:Intestinal Mucosa / Q000201:enzymology; D007527:Isoenzymes / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism; D007668:Kidney / Q000201:enzymology; D007700:Kinetics; D008099:Liver / Q000187:drug effects / Q000201:enzymology*; D008969:Molecular Sequence Data; D011241:Prednisone / Q000494:pharmacology*; D012333:RNA, Messenger / Q000096:biosynthesis* / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000662:veterinary; D017422:Sequence Analysis, DNA; D020539:Sequence Analysis, Protein
D005938:Glucocorticoids; D007527:Isoenzymes; D012333:RNA, Messenger; D000469:Alkaline Phosphatase; D011241:Prednisone