Regulated secretion of atrial natriuretic factor from cultured ventricular myocytes

C. E. Irons, C. A. Sei, C. C. Glembotski

Research output: Contribution to journalArticlepeer-review

18 Scopus citations

Abstract

We have investigated endothelin (ET)-regulated secretion of atrial natriuretic factor (ANF) from primary neonatal rat ventricular myocytes, where hormone release is thought to be constitutive. In a dose-dependent, nifedipine-sensitive manner, ET acutely enhanced ANF release by two- to fivefold over control cultures within 15 min of agonist exposure, demonstrating that ventricular myocytes display a primary characteristic of a regulated secretory cell type. Unlike atrial cultures, ET enhanced ANF release during the first 30 min of exposure; thereafter, secretion rates returned to control levels. KCl, however, effectively enhanced ANF release only during the first 15 min of exposure. Subcellular fractionation of ventricular culture homogenates did not reveal atrial-type dense secretory granules, and pulse-chase labeling experiments showed that the transit time of newly synthesized ANF was short in ventricular myocytes [time required for half of labeled ANF to be released from cells (t( 1/2 )) = 0.5-1.5 h) compared with atrial myocytes (t( 1/2 ) = 4 h). These results suggest that, whereas ventricular myocytes possess some of the characteristics of a constitutively secreting cell type (e.g., few, if any, dense secretory granules and rapid transit time for newly synthesized hormone); however, they also display the capacity for regulated secretion of ANF in response to the physiological agonist ET.

Original languageEnglish (US)
Pages (from-to)H282-H285
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Volume264
Issue number1 33-1
DOIs
StatePublished - 1993
Externally publishedYes

Keywords

  • cardiac myocyte
  • constitutive, regulated secretion
  • secretory granules

ASJC Scopus subject areas

  • Physiology
  • Cardiology and Cardiovascular Medicine
  • Physiology (medical)

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