| Title | Pulse Frequency-Dependent Gonadotropin Gene Expression by Adenylate Cyclase-Activating Polypeptide 1 in Perifused Mouse Pituitary Gonadotroph LbetaT2 cells. | | Author(s) | Kanasaki H, Mutiara S, Oride A, Purwana IN, Miyazaki K | | Source | Biol Reprod 2009 May 20. | | Abstract | We examined how pulsatile stimulation with adenylate cyclase-activating polypeptide 1 (ADCYAP1) affected gonadotrophs. In static culture, gonadotropin-releasing hormone (GnRH) stimulated transcription of all of the gonadotropin subunits. In contrast, ADCYAP1 increased common alpha-glycoprotein subunit gene (Cga) promoter activity, but failed to increase luteinizing hormone beta (Lhb) and follicle-stimulating hormone beta (Fshb) promoters. Messenger RNAs for Lhb and Fshb were slightly but significantly increased by ADCYAP1 stimulation. Co-treatment of the cells with GnRH and ADCYAP1 was not different to the effects of GnRH alone on Lhb and Fshb transcriptional activities as well as mRNA expressions. To determine the effect of pulsatile ADCYAP1 stimulation on gonadotropin subunit gene expression, perifused LbetaT2 cells were stimulated at either high frequency (5 min ADCYAP1 pulse every 30 min) or low frequency (5 min ADCYAP1 pulse every 120 min). High frequency ADCYAP1 pulses preferentially increased Lhb gene expression up to 2.29 +/- 0.15-fold, and low frequency pulses resulted in a 1.55 +/- 0.16-fold increase. Fshb gene expression was increased 1.87 +/- 0.3-fold by high frequency ADCYAP1 pulses and 4.3 +/- 0.29-fold by low frequency pulses. These results were similar to the frequency specific effects of pulsatile GnRH. Follistatin (Fst) gene expression was specifically increased by high frequency GnRH pulses. High frequency ADCYAP1 pulses further increased Fst up to 4.7 +/- 0.57-fold than low frequency pulse (2.72 +/- 1.09-fold). ADCYAP1 receptor gene (Adcyap1r) expression was increased significantly following pulsatile GnRH regardless of pulse frequency. Low frequency ADCYAP1 pulses, however, increased Adcyap1r expression (16.49 +/- 8.41) to a larger extent than did high frequency pulses. Additionally, high frequency ADCYAP1 pulses specifically increased Gnrhr (GnRH receptor) expression by 4.38 +/- 0.81-fold; however, low frequency pulses did not result in an increase. These studies suggest ADCYAP1, like GnRH, specifically regulates Lhb and Fshb subunit gene in a pulse-frequency specific manner. This regulation may involve alteration in numbers of GnRH and ADCYAP1 receptors as well as FST expression. | | Language | ENG | | Pub Type(s) | JOURNAL ARTICLE
| | PubMed ID | 19458315 |
|
