Electric and magnetic phenomena observed before the volcano-seismic activity in 2000 in the Izu Island Region, Japan.

Significant anomalous changes in the ultra low frequency range (approximately 0.01 Hz) were observed in both geoelectric and geomagnetic fields before the major volcano-seismic activity in the Izu Island region, Japan. The spectral intensity of the geoelectric potential difference between some electrodes on Niijima Island and the third principal component of geomagnetic field variations at an array network in Izu Peninsula started to increase from a few months before the onset of the volcano-seismic activity, culminating immediately before nearby magnitude 6 class earthquakes. Appearance of similar changes in two different measurements conducted at two far apart sites seems to provide information supporting the reality of preseismic electromagnetic signals.

5alpha-reduction of an anti-androgen TSAA-291, 16beta-ethyl-17beta-hydroxy-4-estren-3-one, by nuclear 5alpha-reductase in rat prostates.

Inhibition of 5alpha-reduction of testosterone by an anti-androgen TSAA-291 (16beta-ethyl-17beta-hydroxy-4-estren-3-one) was studied in rat ventral prostates and the metabolic conversion of 3H-TSAA-291 was examined both in vitro and in vivo. In the in vitro experiment using nuclear 5alpha-reductase of the prostate, 5alpha-dihydrostestosterone formation from 3H-testosterone was inhibited in a competitive manner by the anti-androgen. In the in vitro experiment using 3H-TSAA-291, 5alpha-reduction of the anti-androgen occurred. One, 2 and 4 hr after an intravenous administration of 140 muCi/rat of 3H-TSAA-291 to castrated rats, the unchanged TSAA-291 accumulated in higher amounts in the ventral prostate than in the plasma, skeletal muscle and levator ani muscle, thereby indicating the selective uptake of the anti-androgen by the androgen target organ. No appreciable amounts of the 5alpha-reduced metabolite of TSAA-291 were detected in the prostate, thus suggesting that TSAA-291 itself may be responsible for the anti-androgenic properties. The inhibitory potency of the 5alpha-reductase activity of several other 16beta-substituted androstane and estrane analogues was also examined.