Growth hormone-releasing factor induces c-fos expression in cultured primary pituitary cells

TY - JOUR

T1 - Growth hormone-releasing factor induces c-fos expression in cultured primary pituitary cells

AU - Billestrup, Nils

AU - Mitchell, R L

AU - Vale, W

AU - Verma, I M

PY - 1987/4

Y1 - 1987/4

N2 - GH-releasing factor (GRF) and somatostatin regulates the secretion and biosynthesis of GH as well as the proliferation of GH-producing cells. In order to further characterize the mitogenic effect of GRF, we studied the expression of the proto-oncogene c-fos in primary pituitary cells. Maximal induction of c-fos mRNA was observed 20-60 min after stimulation with 5 nM GRF, returning to basal levels after 2 h. Somatostatin-14 (5 nM) partially inhibited the GRF induced c-fos expression. Forskolin and phorbol 12, 13 dibutyrate induced c-fos gene in cultured primary pituitary cells with similar kinetics. Transcription of the fos gene was accompanied by biosynthesis of the fos protein. Indirect immunofluorescence using a fos specific antibody, showed exclusive nuclear localization of the fos protein. These data demonstrate that GRF and somatostatin, in addition to regulating GH secretion and somatotroph proliferation, can also regulate the expression of c-fos proto-oncogene in primary somatotrophs.

AB - GH-releasing factor (GRF) and somatostatin regulates the secretion and biosynthesis of GH as well as the proliferation of GH-producing cells. In order to further characterize the mitogenic effect of GRF, we studied the expression of the proto-oncogene c-fos in primary pituitary cells. Maximal induction of c-fos mRNA was observed 20-60 min after stimulation with 5 nM GRF, returning to basal levels after 2 h. Somatostatin-14 (5 nM) partially inhibited the GRF induced c-fos expression. Forskolin and phorbol 12, 13 dibutyrate induced c-fos gene in cultured primary pituitary cells with similar kinetics. Transcription of the fos gene was accompanied by biosynthesis of the fos protein. Indirect immunofluorescence using a fos specific antibody, showed exclusive nuclear localization of the fos protein. These data demonstrate that GRF and somatostatin, in addition to regulating GH secretion and somatotroph proliferation, can also regulate the expression of c-fos proto-oncogene in primary somatotrophs.

KW - Animals

KW - Cells, Cultured

KW - Growth Hormone-Releasing Hormone

KW - Kinetics

KW - Male

KW - Pituitary Gland, Anterior

KW - Proto-Oncogenes

KW - RNA, Messenger

KW - Rats

KW - Rats, Inbred Strains

KW - Transcription, Genetic

U2 - 10.1210/mend-1-4-300

DO - 10.1210/mend-1-4-300

M3 - Journal article

C2 - 3135482

SN - 0888-8809

VL - 1

SP - 300

EP - 305

JO - Molecular endocrinology (Baltimore, Md.)

JF - Molecular endocrinology (Baltimore, Md.)

IS - 4

ER -