Expression of calcium-binding protein regucalcin mRNA in rat liver is stimulated by calcitonin: the hormonal effect is mediated through calcium.
The involvement of a hypocalcemic hormone calcitonin (CT) in the expression of hepatic Ca(2+)-binding protein regucalcin mRNA was investigated. The change of regucalcin mRNA levels was analyzed by Northern blotting using liver regucalcin complementary DNA (0.9 kb). A single oral administration of calcium chloride (100 mg Ca/100 g body weight) to rats induced a remarkable increase in the serum calcium concentration and a corresponding elevation of the liver calcium content during 120 min after the administration. Thyroparathyroidectomy (TPTX) did not cause a significant increase in the liver calcium content after calcium administration. Hepatic regucalcin mRNA level was markedly elevated by calcium administration; the level was about 180% of controls at 60 min after the administration. This increase was completely abolished by TPTX. A single subcutaneous administration of CT (synthetic eel CT; 25-100 MRC mU/100 g) to TPTX rats received oral administration of calcium (100 mg/100 g) produced a remarkable increase in hepatic regucalcin mRNA levels; the level was about 280% of controls with the dose of 25 MRC mU CT/100 g. The present finding suggests that the expression of hepatic mRNA is stimulated by CT, and that the hormonal effect is mediated through Ca2+ in rat liver.
Laboratory of Metabolism and Endocrinology, Graduate School of Nutritional Sciences, University of Shizuoka, Japan.
M
M
Yamaguchi
Y
Y
Kanayama
N
N
Shimokawa
D000818:Animals; D002116:Calcitonin / Q000494:pharmacology*; D002118:Calcium / Q000502:physiology*; D002135:Calcium-Binding Proteins / Q000096:biosynthesis* / Q000235:genetics; D002265:Carboxylic Ester Hydrolases; D005786:Gene Expression Regulation; D006934:Hypercalcemia / Q000139:chemically induced / Q000235:genetics / Q000378:metabolism*; D047908:Intracellular Signaling Peptides and Proteins; D008099:Liver / Q000187:drug effects* / Q000378:metabolism; D016105:Parathyroidectomy; D012333:RNA, Messenger / Q000096:biosynthesis*; D051381:Rats; D017208:Rats, Wistar; D015238:Sulfotransferases; D013965:Thyroidectomy; D014158:Transcription, Genetic / Q000187:drug effects*
D002135:Calcium-Binding Proteins; D047908:Intracellular Signaling Peptides and Proteins; D012333:RNA, Messenger; D002116:Calcitonin; D015238:Sulfotransferases; C028152:alcohol sulfotransferase; D002265:Carboxylic Ester Hydrolases; C513325:Rgn protein, rat; D002118:Calcium