Regulation of thyrotropin-releasing hormone receptors is cell type specific: comparison of endogenous pituitary receptors and receptors transfected into non-pituitary cells.
TRH, which does not elevate cyclic AMP, and elevation of cellular cyclic AMP decrease the density (down-regulate) of TRH receptors (TRH-Rs) on pituitary (GH3) cells. In this study we measured the effects of TRH and elevation of cyclic AMP on TRH-Rs expressed in non-pituitary cells transfected with a recently cloned mouse pituitary TRH-R complementary DNA. In stably transfected rat glioma (C6-2) cells and transiently transfected COS-1 cells TRH caused TRH-R down-regulation while elevation of cyclic AMP caused increases in TRH-R density. Hence, the effects of cyclic AMP on TRH-Rs in transfected C6-2 and COS-1 cells are different from those in GH3 cells while the effects of TRH on TRH-R are similar in all three cell types. These data show that regulation of TRH-Rs is cell type specific.
Gershengorn
M C
MC
Department of Medicine, Cornell University Medical College, New York, New York.
Thaw
C N
CN
D000818:Animals; D002460:Cell Line; D005576:Colforsin / Q000494:pharmacology; D000242:Cyclic AMP / Q000378:metabolism; D004247:DNA; D004305:Dose-Response Relationship, Drug; D005910:Glioma / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D007668:Kidney / Q000166:cytology / Q000378:metabolism* / Q000502:physiology; D051379:Mice; D010902:Pituitary Gland / Q000166:cytology / Q000378:metabolism*; D017981:Receptors, Neurotransmitter / Q000235:genetics / Q000378:metabolism*; D018025:Receptors, Thyrotropin-Releasing Hormone; D013973:Thyrotropin-Releasing Hormone / Q000494:pharmacology; D014162:Transfection; D014407:Tumor Cells, Cultured
D017981:Receptors, Neurotransmitter; D018025:Receptors, Thyrotropin-Releasing Hormone; D005576:Colforsin; D013973:Thyrotropin-Releasing Hormone; D004247:DNA; D000242:Cyclic AMP