PT  - JOURNAL ARTICLE
AU  - M. Issar
AU  - S. Sahasranaman
AU  - P. Buchwald
AU  - G. Hochhaus
TI  - Differences in the glucocorticoid to progesterone receptor selectivity of inhaled glucocorticoids
AID  - 10.1183/09031936.06.00060005
DP  - 2006 Mar 01
TA  - European Respiratory Journal
PG  - 511--516
VI  - 27
IP  - 3
4099  - http://erj.ersjournals.com/content/27/3/511.short
4100  - http://erj.ersjournals.com/content/27/3/511.full
SO  - Eur Respir J2006 Mar 01; 27
AB  - Due to the high affinity of new inhaled corticosteroids (ICS) towards the glucocorticoid receptor (GR), and because of the similarities between the binding domains of the GR and the progesterone receptor (PR), the present study focused on assessing the relative binding affinities (RBA) of glucocorticoids (systemic and ICS) to PR (RBAPR). By comparison with the affinities towards the GR (RBAGR) the binding selectivities were also assessed. In general, the selectivity of the investigated glucocorticoids showed a decreasing trend with increasing lipophilicity. When orally administered, less lipophilic glucocorticoids showed the highest selectivity, with RBAGR/RBAPR ratios of 1,375, 760 and 476 for betamethasone, beclomethasone and dexamethasone, respectively. For ICS, mometasone furoate, the most lipophilic steroid, was the least selective (1.1), followed by beclomethasone monopropionate (9), fluticasone propionate (12), triamcinolone acetonide (18), mometasone (25) and budesonide (44), which shows the highest selectivity among inhaled glucocorticoids. In conclusion, the present study revealed that there are differences in selectivity among commercially available glucocorticoids. Future clinical studies are needed to investigate whether the high affinity of some of the investigated glucocorticoids to the progesterone receptor is of clinical relevance.