Evidence that TRH controls prolactin release from rat lactotrophs by stimulating a calcium influx

Cell Biol Toxicol. 1994 Dec;10(5-6):311-6. doi: 10.1007/BF00755776.

Abstract

Prolactin (PRL) release and intracellular free calcium concentration [Ca2+]i were measured in two populations of normal rat lactotrophs (light and heavy fractions) in culture. Spontaneous PRL release of heavy fraction cells was more sensitive to dihydropyridines (DHPs; Bay K 8644 and nifedipine) when compared to the light fraction lactotrophs. The stimulatory effect of thyrotropin-releasing hormone (TRH) on PRL release from heavy fraction cells was inhibited by Cd2+ and mimicked by Bay K 8644. Indo-1 experiments revealed that TRH-increased [Ca2+]i was reversibly inhibited by Cd2+. In a Ca(2+)-free EGTA-containing medium, TRH did not modify [Ca2+]i.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • 3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester / pharmacology
  • Animals
  • Cadmium / pharmacology
  • Calcium / metabolism*
  • Calcium Channels / drug effects
  • Calcium Channels / physiology
  • Cells, Cultured
  • Culture Media
  • Cytoplasm / metabolism
  • Dihydropyridines / pharmacology*
  • Female
  • Nifedipine / pharmacology
  • Pituitary Gland, Anterior / drug effects
  • Pituitary Gland, Anterior / metabolism*
  • Prolactin / metabolism*
  • Rats
  • Rats, Wistar
  • Thyrotropin-Releasing Hormone / pharmacology*

Substances

  • Calcium Channels
  • Culture Media
  • Dihydropyridines
  • Cadmium
  • Thyrotropin-Releasing Hormone
  • 3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester
  • Prolactin
  • Nifedipine
  • Calcium