17beta-Estradiol modulates gene transcription through the estrogen receptor and the estrogen response element in DNA. The human transforming growth factor-beta3 gene was shown to be activated by the estrogen receptor in the presence of estrogen metabolites or estrogen antagonists. Activation was mediated by a polypurine sequence, termed the raloxifene response element, and did not require the DNA binding domain of the estrogen receptor. Interaction of the estrogen receptor with the raloxifene response element appears to require a cellular adapter protein. The observation that individual estrogens modulate multiple DNA response elements may explain the tissue-selective estrogen agonist or antagonist activity of compounds such as raloxifene.

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The 2-arylbenzothiophene raloxifene, 1, is a selective estrogen receptor modulator (SERM) which is currently under clinical evaluation for the prevention and treatment of postmenopausal osteoporosis. In vivo structure-activity relationships and molecular modeling studies have indicated that the orientation of the basic amine-containing side chain of 1, relative to the stilbene plane, is an important discriminating factor for the maintenance of tissue selectivity. We have constructed a series of analogues of 1 in which this side chain is held in an orientation which is orthogonal to the stilbene plane, similar to the low-energy conformation predicted for raloxifene. Herein, we report on the synthesis of these compounds and on their activity in a series of in vitro and in vivo biological assays reflective of the SERM profile. In particular, we describe their ability to (1) bind the estrogen receptor, (2) antagonize estrogen-stimulated proliferation of MCF-7 cells in vitro, (3) stimulate TGF-beta3 gene expression in cell culture, (4) inhibit the uterine effects of ethynyl estradiol in immature rats, and (5) potently reduce serum cholesterol and protect against osteopenia in ovariectomized (OVX) rats without estrogen-like stimulation of uterine tissue. These data demonstrate that one of these compounds, LY357489,4, is among the most potent SERMs described to date with in vivo efficacy on bone and cholesterol metabolism in OVX rats at doses as low as 0.01 mg/kg/d.

Aim : Tadalafil is an inhibitor of phosphodiesterase type 5 used for the treatment of erectile dysfunction (ED). The efficacy and safety of tadalafil have been evaluated extensively in Western populations. Our aim was to assess the efficacy and safety of ondemand tadalafil for the treatment of ED in South-East Asian men. Methods : This was a randomized, double-blind, placebo-controlled study of men with mild to severe ED of various etiologies randomized to receive placebo ( n = 122), tadalafil 10 mg ( n = 120), or tadalafil 20 mg ( n = 125), taken as needed (maximum once daily) for 12 weeks. Efficacy assessments included the International Index of Erectile Function (IIEF), the Sexual Encounter Profile (SEP) diary, and a Global Assessment Question (GAQ). Results : Men from China, Singapore, and the Philippines participated in this trial ( n = 367). Compared with placebo, tadalafil significantly improved erectile dysfunction on all efficacy outcomes ( P < 0.001). Patients receiving tadalafil 10 mg and 20 mg experienced a significant mean improvement of 8.1 and 8.7, respectively, in the IIEF Erectile Function (IIEF-EF) domain score from baseline (vs placebo 2.4, P < 0.001). In patients receiving tadalafil 10 mg and 20 mg, the mean per-patient success rate for intercourse attempts (SEP3) was 62% and 70%, respectively, compared with 32% for the placebo group ( P < 0.001). Of patients who received tadalafil 10 mg and 20 mg, 81% and 86% reported improved erections at endpoint (GAQ) compared with 44% in the placebo group ( P < 0.001). The most common adverse events reported by patients were headache, back pain, dyspepsia, and dizziness. Conclusions : Tadalafil was an effective and well-tolerated treatment for South-East Asian men with ED.