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Updated: Sep 20, 2026
Mouse Model of Surgically-induced Endometriosis by Auto-transplantation of Uterine Tissue
Published on: January 6, 2012
Effects of the novel orally active antiestrogen TZE-5323 on experimental endometriosis
Tomoyuki Saito1, Masayuki Yoshizawa, Yukinao Yamauchi
1Pharmacology Department, Teikoku Hormone Mfg. Co., Ltd., Kawasaki, Kanagawa, Japan. saito-t1@kw.teikoku-hormone.co.jp
Abstract:
Danazol and gonadotropin-releasing hormone agonists which are used as therapeutic drugs for endometriosis, develop adverse reactions in association with their long-term use. The efficacy of anti-estrogens for endometriosis, an estrogen-dependent disorder, has not been demonstrated. A novel, orally active anti-estrogen, TZE-5323 ((2-cyclohexy-6-hydroxybenzo[b]thien-3-yl)[4-[2-(1- piperidinyl)ethoxy]phenyl] methanone hydrochloride, CAS 150797-71-0; free salt formula) was developed. TZE-5323 showed strong affinity for human estrogen receptor alpha (hER alpha) and beta (hER beta), and dose-dependently inhibited estradiol-stimulated transcriptional activation via hER alpha and hER beta. Furthermore, TZE-5323 dose-dependently reduced estrogen-increased uterine weight in ovariectomized rats. Tamoxifen showed agonistic activity on hER alpha, while TZE-5323 did not show such activity. In the experimental endometriosis model in rats in which endometrial tissue is autotransplanted into the renal subcapsular space, TZE-5323 dose-dependently reduced the volume of the endometrial implant as did danazol and leuprorelin acetate. Furthermore, the long-term administration of TZE-5323 neither showed a decrease in bone mineral density nor did it affect serum estradiol concentrations in intact rats. Therefore, TZE-5323 suggested its potential as a novel therapeutic drug for endometriosis which is effective also in long-term use.
Insights
A new anti-estrogen drug, TZE-5323, effectively treats endometriosis in rats without adverse effects like bone loss. This novel compound shows promise for long-term endometriosis therapy.
Area of Science:
- Endocrinology
- Pharmacology
- Reproductive Medicine
Background:
- Endometriosis is an estrogen-dependent disorder with limited long-term therapeutic options.
- Current treatments like danazol and GnRH agonists cause adverse reactions with prolonged use.
- The efficacy of anti-estrogens for endometriosis has not been established.
Purpose of the Study:
- To evaluate the efficacy and safety of a novel orally active anti-estrogen, TZE-5323, for endometriosis treatment.
- To assess TZE-5323's interaction with estrogen receptors and its effects on estrogen-sensitive tissues.
- To compare TZE-5323's performance against existing endometriosis therapies in an animal model.
Main Methods:
- TZE-5323 was tested for binding affinity and functional activity at human estrogen receptors alpha and beta (hER alpha and hER beta).
- In vivo studies included assessing TZE-5323's effect on uterine weight in ovariectomized rats and its efficacy in a rat endometriosis model.
- Long-term safety was evaluated by monitoring bone mineral density and serum estradiol levels in intact rats.
Main Results:
- TZE-5323 demonstrated strong affinity for hER alpha and hER beta, inhibiting estradiol-stimulated activity.
- The compound dose-dependently reduced uterine weight and endometrial implant volume in experimental models.
- Unlike tamoxifen, TZE-5323 did not exhibit agonistic activity on hER alpha.
- Long-term administration of TZE-5323 did not compromise bone mineral density or alter estradiol levels.
Conclusions:
- TZE-5323 exhibits potent anti-estrogenic activity and efficacy in preclinical models of endometriosis.
- The drug's safety profile, particularly regarding bone health and hormonal balance, suggests suitability for long-term use.
- TZE-5323 represents a promising novel therapeutic candidate for managing endometriosis.
