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Dihydrotestosterone and progesterone relax female guinea pig gallbladder strips
Author(s) -
Kline Loren,
Karpinski Edward
Publication year - 2008
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.22.1_supplement.1186.1
Subject(s) - dihydrotestosterone , endocrinology , medicine , guinea pig , chemistry , chelerythrine , relaxation (psychology) , androgen , hormone , biology , protein kinase c , enzyme , biochemistry
We demonstrated that dihydrotestosterone (DHT) and progesterone (P) relaxed cholecystokinin octapeptide (CCK) induced tension in male guinea pig strips; however, the effects of DHT and P on female guinea pig strips has not been fully studied. An in vitro technique was used. Statistical analyses used either paired t‐test or analysis of variance. DHT, P, 17‐hydroxyprogesterone (17‐P) or 20α–hydroxyprogesterone (20‐P; 10 μM 50 μM, and 100 μM) were used to generate concentration response curves. All 4 agents induced a concentration dependent relaxation of CCK‐induced tension. There was no significant difference between the P‐ and 17‐P‐induced relaxations. 20‐P induced significantly (P<0.05) less relaxation than P. DHT produced a relaxation similar to that induced by P and 17‐P. The relaxation caused by 50 μM and 100 μM DHT were not significantly different (63.7±5.1 vs. 63.5±6.5%). The response to 100 μM DHT was significantly less (p<0.01) than 100 μM P (91.0±6.2%). To determine if the PKA/cAMP second messenger system mediated the P‐ or DHT‐induced relaxation, PKA inhibitor 14‐22 amide myristolated (PKA‐IM; 180 nM) was used. PKA‐IM caused a significant (p<0.05) decrease in P‐induced relaxation (73.5±7.9 vs. 64.2±7.0%), but had no significant effect on DHT‐induced relaxation. When the PKC inhibitors bisindolymaleimide IV (0.5 μM) and chelerythrine Cl (5 μM) were used together, a significant (P<0.05) reduction in both P‐ and DHT‐induced relaxation (P, 56.8±4.0 vs. 36.8±6.2%; DHT, 53.0±6.3 vs. 42.5±5.1%) was observed. The results suggest that both the PKA/cAMP and PKC second messenger systems mediated the P‐induced relaxation of CCK‐induced tension in female guinea pig gallbladder strips. Only the PKC system mediates the DHT‐induced relaxation.