| Autor: |
Juengel, Jennifer L., Haydon, Lisa J., Sabatou, Claire, Young, Julia M., Edwards, Sara J. |
| Zdroj: |
Biology of Reproduction; May 2008, Vol. 78 Issue: 1, Number 1 Supplement 1 p287-287, 1p |
| Abstrakt: |
Adrenomedullin has been shown to increase cAMP concentrations in rat granulosa cells and is negatively regulated by gonadotrophins. It is also present in follicular fluid recovered from women undergoing in vitro fertilization and is expressed by human granulosa-lutein cells in culture. Furthermore, adrenomedullin stimulated progesterone secretion by these cells. However, little is known about the expression or function of adrenomedullin during follicular development in many species. The aims of this study in sheep were to determine the pattern of expression of adrenomedullin during ovarian follicular development including preovulatory maturation and to determine the relationship between adrenomedullin and aromatase mRNA. Using in situ hybridization, expression of adrenomedullin was observed in both the granulosa and thecal cells of healthy and atretic antral follicles with expression being more evident in atretic follicles. Little if any expression was observed in type 1-3 follicles but low levels were detected in type 4 follicles. Large antral follicles (> 4.5 mm diameter) were collected 24 hours after induction of the follicular phase with prostaglandin F2alpha (N=18 follicles from 15 ewes with only 1-2 follicles per ewe). Relative levels of adrenomedullin and aromatase mRNAs were determined using a quantitive PCR method. A negative correlation was observed between aromatase and adrenomedullin mRNA expression (y = 0.0386x-0.9309; R2= 0.8224). Following ranking of follicles on aromatase expression, the follicles were evenly divided into two groups based on high or low aromatase expression (high group average 1.36 ± 0.22, range 0.50-2.32 units; low average 0.16 ± 0.05, range 0.01-0.44 units). Expression of adrenomedullin in the low aromatase expression group was >12 fold higher (P<0.01; t-test) than the high aromatase expression group. In summary, both the granulosa and thecal cells of large preantral and antral follicles expressed mRNA encoding adrenomedullin. Expression of adrenomedullin mRNA appeared stronger in atretic antral follicles than in healthy antral follicles. In large antral follicles collected 24 hours after induction of the follicular phase, adrenomedullin expression was negatively correlated with aromatase mRNA expression. |
| Databáze: |
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