Searchable abstracts of presentations at key conferences on reproductive biology and medicine
Reproduction Abstracts (2014) 1 P304 | DOI: 10.1530/repabs.1.P304

WCRB2014 POSTER PRESENTATIONS (1) (335 abstracts)

The relaxing effect of dihydrotestosterone on myometrial smooth muscle contraction is mediated via blockage of intracellular calcium increase and inhibition of myosin light chain phosphorylation

Sofia Makieva , Philippa T K Saunders & Jane E Norman

University of Edinburgh, Edinburgh, UK.

Background: The impact of androgens on myometrial contraction has received less scrutiny, compared to progesterone and estrogens. We sought to i) examine the effect of dihydrotestosterone (DHT; a non-aromatizable androgen) on stretch-induced contraction of human myometrium and ii) gain mechanistic insights by studying changes in intracellular calcium [Ca2+] and phosphorylation of myosin light chain (MLC).

Methods: Myometrial strips were recovered from biopsies obtained from women undergoing elective caesarean delivery at term prior initiation of labour. Strips were placed under tension in a tissue-bath system and allowed to develop spontaneous contractions. Contractions were quantified before and after addition of DHT (10–100 μM, 30 min). A myometrial smooth muscle cell line (PHM1-41s) was used to measure [Ca2+] concentrations (Fluo-4 calcium assays) and phosphorylation of MLC (in-cell western); oxytocin (OXT) was used as a positive control.

Results: Addition of DHT relaxed spontaneous myometrial contractions in a dose dependent fashion: amplitude of contractions was 5%±3% of controls following addition of 100 μM (n=7 women, P<0.001). Treatment of PHM1-41s with OXT (10 nM) increased [Ca2+] (P<0.001, n=7) and significantly increased phosphorylation of MLC (OXT 100 nM, P<0.0001, n=6). Pre-treatment with DHT for 15 min blunted the OXT effect on [Ca2+] (DHT: 800 nM; P<0.05, n=6) and phosphorylation of MLC (DHT: 50 μM; P<0.05, n=6).

Conclusions: DHT inhibits myometrial smooth muscle contraction. The mechanism of this effect may involve the blockage of increases in intracellular Ca2+ and phosphorylation of MLC.

Volume 1

World Congress of Reproductive Biology 2014

Edinburgh, UK
02 Sep 2014 - 04 Sep 2014

World Congress of Reproductive Biology 

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