Androgen responsiveness of the pituitary gonadotrope cell line LbetaT2.
Androgens have a profound effect on the hypothalamic-pituitary axis by reducing the synthesis and release of the pituitary gonadotropin LH. The effect on LH is partly a consequence of a direct, steroid-dependent action on pituitary function. Although androgen action has been well studied in vivo, in vitro cell models of androgen action on pituitary gonadotropes have been scarce. Recently, an LH-expressing cell line, LbetaT2, was generated by tumorigenesis targeted to the LH-producing cells of the mouse pituitary. The purpose of these studies was to determine the presence of androgen receptor (AR) and establish its function in this cell line. RT-PCR analysis indicated that the LbetaT2 cell line expresses AR mRNA. Transient transfection assays, using the mouse mammary tumor virus (MMTV) promoter, showed that a functional AR is also present. Testosterone (TEST), dihydrotestosterone (DHT), 7alpha-methyl-19-nortestosterone (MENT), and fluoxymesterone (FLUOXY) increased reporter gene activity in the rank order of potencies MENT>DHT> TEST>FLUOXY. Additionally, activation of MMTV promoter activity by DHT in LbetaT2 cells was diminished by the AR antagonists casodex and 2-hydroxy-flutamide, indicating that the effects of DHT are mediated through AR. In summary, these studies showed that the LbetaT2 cell line is a useful model for the evaluation and molecular characterization of androgen action in pituitary gonadotropes.
Lawson
M A
MA
Department of Pharmacology, Ligand Pharmaceuticals Inc., 10275 Science Center Drive, San Diego, California 92121, USA.
Li
D
D
Glidewell-Kenney
C A
CA
López
F J
FJ
D059002:Androgen Receptor Antagonists; D000728:Androgens / Q000494:pharmacology*; D000818:Animals; D013196:Dihydrotestosterone / Q000494:pharmacology; D015870:Gene Expression; D017930:Genes, Reporter; D007986:Luteinizing Hormone / Q000096:biosynthesis; D051379:Mice; D010903:Pituitary Gland, Anterior / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics; D011944:Receptors, Androgen / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014407:Tumor Cells, Cultured
D059002:Androgen Receptor Antagonists; D000728:Androgens; D012333:RNA, Messenger; D011944:Receptors, Androgen; D013196:Dihydrotestosterone; D007986:Luteinizing Hormone