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Original Articles
- Regulation of Prolactin Gene Expression by Hypothalamic Pituitary Adenylate Cyclase-Activating Polypeptide (PACAP) in the Female Rat Pituitary Gland.
- Young Il Kim, Tae Young Ha, Eun Sook Kim, Il Seong Nam-Goong, M S O'Dorisio, Min Kyu Hur, Sang Kyu Park
- J Korean Endocr Soc. 2004;19(2):152-164. Published online April 1, 2004
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Abstract
PDF - BACKGROUND
Pituitary adenylate cyclase-activating polypeptide (PACAP) plays the role of a hypophysiotropic factor, which regulates the synthesis and secretion of pituitary hormones through the hypothalamo-hypophysial portal system. No clear evidence has yet been reported regarding the regulation of prolactin (PRL) by PACAP. In the present study, we tested a hypothesis that PACAP regulates the synthetic machinery of PRL during the estrus cycle and pubertal process using intracerebroventricular (i.c.v.) injection of an antisense oligodeoxynucleotide (ODN) against type I PACAP receptor (PAC1). METHODS: An RNase protection assay (RPA) was used to determine the pattern of hypothalamic PACAP and PAC1 mRNA expressions during the estrus cycle. Antisense PAC1 ODN was administered via i.c.v. injection to the female rats in normal estrus cycle of pubertal process. Northern blot analysis was used to determine the mRNA ievel of PRL in the pituitary gland. RESULTS: 1) PACAP mRNA in the medial basal hypothalamus was significantly increased at the diestrus I, while PAC1 mRNA showed no significant change. 2) PRL mRNA level of pituitary was increased by an injection of antisense PAC1 ODN at the proestrus and estrus stages. 3) PRL mRNA level of pituitary was significantly decreased by antisense PAC1 ODN injection at stage of prepuberty and initiate puberty, while its level was increased at stage of puberty. CONCLUSION: These data suggest that PACAP suppresses PRL mRNA synthesis through the PAC1 signaling pathway in the certain estrus cycle environments. It may be also involved in the regulation of pituitary PRL gene expression during the pubertal process
- Interaction of Pituitary Adenylate Cyclase-Activating Polypeptide and Angiotensin II on Aldosterone Production in Human Adrenocortical H295R Cells.
- Seong Yeon Kim, Sang Wan Kim, Young Min Cho, Do Joon Park, Chan Soo Shin, Kyung Soo Park, Bo Youn Cho, Hong Kye Lee
- J Korean Endocr Soc. 2003;18(3):272-282. Published online June 1, 2003
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Abstract
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- BACKGROUND
Evidence is accumulating that aldosterone secretion can be regulated in a paracrine and/or an autocrine manner by several neuropeptides locally released within the adrenal gland. Among neuropeptides, pituitary adenylate cyclase-activating polypeptide (PACAP) is present in high concentration in the human adrenal gland. The purpose of this study was to investigate the action of PACAP and the interaction between PACAP and angiotensin II (AII), the main physiologic aldosterone secretagogue, in aldosterone production in human H295R adrenocortical cells. METHODS: H295R cells were incubated with increasing concentrations of PACAP (10(-11)M~10(-7)M) in the absence or presence of 10(-7)M AII. Aldosterone concentration in the supernatant was determined by RIA. Intracellular cAMP content was measured by RIA and total inositol phosphate (IP) production by anion exchange chromatography. Gene expression of CYP11B2 was studied by RT-PCR. RESULTS: In H295R cells, PACAP stimulated aldosterone production in a dose-dependent manner. Incubation of H295R cells with PACAP in the presence of AII significantly increased aldosterone production, compared with that of PACAP alone. PACAP dose-dependently increased cAMP production, but 10(-7)M AII had no effect on either basal or PACAP-stimulated cAMP production. Total IP production was not affected by PACAP, but was increased by 10(-7)M AII; an increase that was not further increased by addition of PACAP. RT-PCR analysis of H295R cells which were exposed to 10-7M PACAP or 10(-7)M AII showed an increase in CYP11B2 transcript signal. Induction of CYP11B2 mRNA expression in response to treatment with both PACAP and AII was significantly more than that resulting from using PACAP alone. CONCLUSION: The present study demonstrates that PACAP exerts a direct stimulatory effect on aldosterone production through induction of CYP11B2 mRNA expression by adenylate cyclase activation as the main intracellular signal pathway in H295R cells. Furthermore, there may be some additive effects between PACAP and AII on aldosterone production.
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