PREVALENCE AND TURNOVER OF PEPTIDYLGLYCINE ALPHA-AMIDATING MONOOXYGENASE MESSENGER-RNA IN ATRIAL CARDIOMYOCYTES

Peptidylglycine alpha-amidating monooxygenase (FAM), the enzyme respon sible for the alpha-amidation of neuroendocrine peptides, is more prev alent in the atrium of the heart in pituitary or brain. RNase protecti on assays indicate that PAM transcripts account for approximately 0.5% of the mRNA in the neonatal atrium and 0.06% of the mRNA in the neona tal ventricle. In primary atrial cardiomyocyte cultures PAM mRNA turns over slowly, with a half-life of approximately 20 h. Levels of PAM mR NA in primary atrial cardiomyocytes are increased to 165% of control u pon treatment with dexamethasone and decreased to 63% of control upon treatment with thyroid hormone. (C) 1996 Academic Press Limited