Monensin influences basal and human growth hormone-releasing hormone 44-induced release of stored and new rat growth hormone and prolactin

P. K. Farmer, J. M. Tyler, M. E. Stachura

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7 Scopus citations


When previous data suggested a growth hormone-releasing factor (GRF)-sensitive branch in intracellular hormone processing, the monensin-sensitive Golgi apparatus seemed a likely candidate. We examined monensin's effect on basal and GRF-stimulated release of newly synthesized and stored rat growth hormone (rGH) and rat prolactin (rPRL). 14C-Pre-labeled, perifused rat pituitary fragments were exposed to [3H]leucine in 0-10 fiM monensin; a pulse of 3 nM GRF assessed subsequent secretory responsivity. Monensin dose-dependently reduced basal release of stored [14C]rGH and [14C]rPRL. GRF timulated release of stored [14C]hormone was doubled after 0.03 μM and 0.1 μM monensin; higher concentrations diminished stored hormone release. Low concentrations of monensin accelerated basal (0.03 μM and 0.1 μM) and GRF-stimulated (0.03 μM) [3H]rGH and [3H]rPRL release without altering recovery; higher monensin concentrations (≥1 μM) reduced basal, and abolished GRF-stimulated, new hormone release and reduced total [3H]rGH and [3H]rPRL recovery. These data are consistent with a GRF-sensitive and monensin-influenced branch in intracellular hormone processing that regulates the fraction of new hormone exiting the cell without prior immersion in storage compartments.

Original languageEnglish (US)
Pages (from-to)253-262
Number of pages10
JournalMolecular and Cellular Endocrinology
Issue number2
Publication statusPublished - Apr 1989



  • Growth hormone
  • Growth hormone releasing hormone
  • Hormone, newly synthesized
  • Hormone, stored
  • Monensin
  • Prolactin

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Endocrinology

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