Complementary DNA cloning, tissue distribution, and synthesis of canine brain natriuretic peptide

Objective-To determine complimentary DNA (cDNA) sequence and tissue distrib ution of canine brain natriuretic peptide (BNP), and to investigate whether synthesis of canine BNP increases in association with cardiovascular dysfu nction. Animals-5 healthy adult mixed-breed dogs and 3 healthy adult Beagles. Procedure-Total RNA was extracted from normal canine hearts and was used in a reverse transcription-polymerase chain reaction IRT-PCR) procedure to is olate canine BNP cDNA. Sequence of the isolated cDNA was analyzed. Gene exp ression of canine BNP in various tissues from 2 mixed-breed dogs was invest igated, using RT-PCR and northern blot analyses. Moreover, messenger RNA (m RNA) expression of canine BNP, using northern blot analysis, was compared b etween grossly normal hearts from 3 Beagles and hearts from 3 mixed-breed d ogs with acute myocardial infarction created by surgical ligation. Results-The cDNA sequence and deduced amino acid residues of canine BNP pre cursor were 420 base pairs and 140 residues, respectively. Messenger RNA ex pression of canine BNP was delectable in the atria but not in the ventricle s and the other tissues. Messenger RNA expression of canine BNP was, howeve r, detectable in the infarcted portion of the ventricles. The amount of can ine BNP mRNA in the infarcted ventricles was significantly increased, compa red with that of noninfarcted ventricles. Conclusion-The cDNA sequence of canine BNP was determined. Expression of ca nine BNP mRNA was detected not only in the atria but also in infarcted vent ricles. Synthesis of canine BNP increases in association with ischemic myoc ardial injury. Canine BNP may be used as an indicator of severity of ventri cular myocardial injury.