Pro-opiomelanocortin (POMC) is the precursor of many neuropeptides which includ adrenocorticotropin (ACTH). ACTH has a biological activity in regulating adrenocortical function. In the present study, we will investigate the effect of POMC gene transfer on adrenal cortex cells in cell cultures and animal models. The study included adrenal cortical H295R cells for adenovirus-mediated gene delivery. The effects of POMC gene on H295R cell steroidogenesis and cell proliferation were investigated. In addition, there were 32 SD rats dividing into three groups. 1) Control, injected with normal saline via tail vein (n = 8); 2) Ad-GFP, injected with adenovirus containing GFP (n=12); 3) Ad-POMC, injected with adenovirus containing recombinant POMC gene (n=12). Body weight (BW) was measured. Adrenals were collected, fixed and a series of sections were cut for stains for PCNA and MC2-R. The plasma cortisol and VEGF levels of rats were measured. The results showed that Ad-POMC delivery significantly increased the ACTH and cortisol levels by 50-100 fold and 20-100% in H295R cells, respectively. In addition, Ad-POMC delivery significantly inhibited the cell proliferation and increased the apoptotic cells. The expression of MC2-R protein of H295R cells was also suppressed after Ad-POMC delivery. In the study of SD rats, the Ad-POMC-treated rats exhibited reduced weight gain compared with other groups in the first 2 weeks; however, there was no significant change in BW between Ad-POMC and Ad-GFP groups during the experimental period. The weight of adrenal in Ad-POMC-treated rats was significantly higher than Ad-GFP group in the 8th week. Comparing the sequential adrenal weights in Ad-POMC group, those in 6th week were significantly higher than in 2nd and 4th weeks. The plasma VEFG levels of Ad-POMC-treated rats were higher than Ad-GFP group in the 8th week. The adrenal sections showed that Ad-POMC treated rats had moreanti-PCNA stained cells than Ad-GFP treated rats in 8th week. However, less anti-MC2R stained cells were found in Ad-POMC treated rats in 8th week. Ad-POMC treated rats had higher plasma cortisol levels than those in Ad-GFP treated rats, however, there were no statistical significances. In conclusion, POMC gene transfer modulates the morphology and function of the adrenal cortex. POMC gene inhibits the H295R cells proliferation by inducing MC2-R down-regulation and cells apoptosis. In SD rat adrenal, however, it stimulates adrenal cortex in biphasic pattern. The rapid growing pattern noted in the later phase may be due to the effect of VEGF. Besides, the physical regulation of cortisol synthesis is much stricter than that of ACTH.
| Identifer | oai:union.ndltd.org:NSYSU/oai:NSYSU:etd-0203106-174326 |
| Date | 03 February 2006 |
| Creators | Chu, Chih-Hsun |
| Contributors | Ching-Mei Hsu, Ming-Hong Tai, Hing-Chung Lam |
| Publisher | NSYSU |
| Source Sets | NSYSU Electronic Thesis and Dissertation Archive |
| Language | Cholon |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0203106-174326 |
| Rights | withheld, Copyright information available at source archive |
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