In the ovary, 11βHSD enzymes inter-convert cortisol (F) with its inert metabolite, cortisone (E). Porcine follicular fluid from antral follicles and spontaneous ovarian cysts contains hydrophobic compounds that inhibit NADP(H)-dependent cortisol metabolism by 11βHSD1. The aim of this study was to measure intra-follicular F:E ratios in porcine antral follicles and ovarian cysts, and determine whether F:E ratios correlate with the inhibition of 11βHSD1 by porcine follicular fluid and cyst fluid. Samples of porcine follicular fluid were aspirated from small (2 mm diameter), medium (4 mm and 6 mm diameter) and large antral follicles (≥8 mm diameter), and ovarian cysts (25–40 mm diameter) (n=4 in each case). F and E concentrations were each measured by radioimmunoassay, Table 1.
Table 1 Intra-follicular corticosteroid concentrations and F:E ratios in antral follicles and ovarian cysts
|Follicle category||F (nM)||E (nM)||F:E|
|Medium (4 mm)||140±27a||23±4a||6.1a,b|
|Medium (6 mm)||166±25a,b||27±5a||6.6a,b|
[data with different superscripts differ significantly: P<0.05]
The intra-follicular F:E ratio increased with follicle diameter but was significantly decreased in ovarian cysts relative to large antral follicles (P<0.05). Previously, we have reported that porcine follicular fluid from small antral follicles and ovarian cysts exerts the greatest inhibition of 11βHSD1. We conclude that high levels of ovarian inhibitors of 11βHSD1 are associated with low F:E ratios in growing porcine antral follicles and ovarian cysts, whereas an elevated F:E ratio is associated with a decreased level of 11βHSD1 inhibitors in dominant follicles.
This work was supported by CASE studentship BBS/S/L/2003/10221 BBSRC and Sygen International Plc.
07 - 09 Nov 2005
Society for Endocrinology