Binding of mepartricin to sex hormones, a key factor of its activity on benign prostatic hyperplasia.

Androgens and estrogens, mainly testosterone (TES) and dihydrotestosterone (DHT) and 17 beta-estradiol (EST), are widely recognized to regulate the prostate growth and their imbalance with aging, leading to reduction of androgens and relative increase of estrogens, may be responsible for the development of benign prostatic hyperplasia (BPH). Mepartricin (CAS 11121-32-7), a polyene drug for medical treatment of BPH, was assayed in vitro for its ability to bind with 14C-labelled sex hormones, by incubation in buffered saline, serum and bile, followed by centrifugation and dosing of the radioactivity in the supernatant. It proved effective in complexing up to 90% of TES and DHT in buffered saline and up to 80% of EST in bile. Due to minimal absorption of oral mepartricin and to much higher enterohepatic circulation for estrogens than for androgens, the binding effect of mepartricin on EST in the gut should be of particular pharmacological relevance to explain its mechanism of action on BPH.

Static and ELF magnetic fields induce tumor growth inhibition and apoptosis.

The ability of static and extremely low frequency (ELF) Magnetic Fields (MF) to interfere with neoplastic cell function has been evaluated. In vitro experiments were carried out to study the role of MF characteristics (intensity, frequency, and modulation) on two transformed cell lines (WiDr human colon adenocarcinoma and MCF-7 human breast adenocarcinoma) and one nontransformed cell line (MRC-5 embryonal lung fibroblast). Increase in cell death morphologically consistent with apoptosis was reported exclusively in the two transformed cell lines. Cell-death induction was observed with MF of more than 1 mT. It was independent of the MF frequency and increased when modulated MF (static with a superimposition of ELF at 50 Hz) were used. Based on the in vitro results, four different MF exposure characteristics were selected and used to treat nude mice xenografted with WiDr cells. The treatment of nude mice bearing WiDr tumors subcutaneously. with daily exposure for 70 min to MF for 4 weeks caused significant tumor growth inhibition (up to 50%) by the end of the treatment when modulated MF were used for at least 60% of the whole treatment period and the time-averaged total MF intensity was higher than 3.59 mT. No toxic morphological changes induced by exposure were observed in renewing, slowly proliferating, or static normal cells. A discussion on the possible biophysical mechanism at the base of the observed biological results is also offered.