Characterization of a hepatic protein in nonhuman primates that binds mibolerone but not dihydrotestosterone or methyltrienolone.

During our studies of the hepatic androgen receptor in cynomolgus monkeys, tritiated mibolerone +/- a 200-fold excess of unlabeled mibolerone has been used to determine specific binding in cytosol. During time-course studies, high-capacity, unsaturable binding of [3H]mibolerone was noted after short-term incubations (4 h, 4 degrees C). When hepatic cytosol from male monkeys was incubated for 18 h at 4 degrees C, the high-capacity binding disappeared; saturable, high-affinity binding with characteristics consistent with the androgen receptor then could be identified.

Noradrenergic vasorelaxation of porcine coronary arteries is enhanced by direct, acute exposure to 17 beta-estradiol.

1. We tested whether responses of isolated coronary arteries to adrenergic agents are altered by overnight (18-22 hr) or acute exposure to physiological levels of 17 beta-estradiol. 2.

17 beta-estradiol treatment increases the levels of estrogen receptor and its mRNA in male rat liver.

This study examined estrogen receptor dynamics in the livers of male obese rats (SHHF/Mcc-cp) treated for two weeks with a continuous, low dose of 17 beta-estradiol compared with untreated controls. An increased binding capacity for tritiated 17 beta-estradiol in the cytosol, consistent with binding to the estrogen receptor, was demonstrated in treated males relative to control males (P < 0.01).

Estrogen pretreatment directly potentiates endothelium-dependent vasorelaxation of porcine coronary arteries.

We tested whether vasorelaxation of coronary arteries is altered after overnight (18-22 h) exposure to physiological levels of 17 beta-estradiol. Ring segments of left circumflex coronary artery from six female and six castrated male pigs were incubated in vials of sterile Dulbecco's modified Eagle's medium with 1 nM 17 beta-estradiol, 1 nM 17 beta-estradiol + 10 nM tamoxifen, 1 nM 17 alpha-estradiol, or estrogen vehicle (ethanol) under normoxic conditions in an O2-CO2 incubator at 37 degrees C for 18-22 h. Coronary rings, with and without endothelium, were then suspended in vessel baths for measurement of isometric force.