7 results on '"Yun Yen"'
Search Results
2. Nestorone®: clinical applications for contraception and HRT
- Author
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Yun-Yen Tsong, Narender Kumar, Margaret Small, Regine Sitruk-Ware, Kalyan Sundaram, and Theodore M. Jackanicz
- Subjects
Ovulation ,medicine.medical_specialty ,Time Factors ,Hormone Replacement Therapy ,medicine.drug_class ,media_common.quotation_subject ,medicine.medical_treatment ,Clinical Biochemistry ,Pharmacology ,Ethinyl Estradiol ,Biochemistry ,chemistry.chemical_compound ,Endocrinology ,Internal medicine ,Progesterone receptor ,Contraceptive Agents, Female ,Animals ,Humans ,Endocrine system ,Medicine ,Molecular Biology ,Progesterone ,media_common ,business.industry ,Organic Chemistry ,Hormone replacement therapy (menopause) ,19-Norprogesterone ,Vaginal ring ,Rats ,Contraception ,Models, Chemical ,chemistry ,Hormone receptor ,Estrogen ,Female ,business ,Norprogesterones ,Protein Binding - Abstract
The 19-nor derivatives of progesterone are referred to as “pure” progestational molecules as they bind almost exclusively to the progesterone receptor (PR) without interfering with receptors of other steroids. In this category is Nestorone ® , which has strong progestational activity and antiovulatory potency with no androgenic or estrogenic activity in vivo. These properties make it highly suitable for use in contraception and hormonal therapy (HT). Due to its high potency, very low doses of Nestorone may be delivered via long-term sustained-release delivery systems. Nestorone, 75 or 100 μg per day, released by vaginal ring has suppressed ovulation in women, with inhibition of follicular maturation. A vaginal ring releasing both 150 μg of Nestorone and 15 μg of ethinyl estradiol per day has effectively suppressed ovulation for 13 consecutive cycles. Nestorone has also been used effectively in a single implant for contraception in breastfeeding women and shows promise for use in transdermal systems as a contraceptive or for HT when combined with estrogen.
- Published
- 2003
3. Synthesis and progestational activity of 16-methylene-17α-hydroxy-19-norpregn-4-ene-3,20-dione and its derivatives
- Author
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C. Wayne Bardin, Yun-Yen Tsong, Fang Li, Narender Kumar, and Carl Monder
- Subjects
Stereochemistry ,Clinical Biochemistry ,Butyrate ,Biology ,Biochemistry ,Rats, Sprague-Dawley ,Acylation ,Endocrinology ,In vivo ,Contraceptive Agents, Female ,Animals ,Humans ,Receptor ,Molecular Biology ,Pharmacology ,Progesterone Congeners ,Organic Chemistry ,Biological activity ,In vitro ,Rats ,Alkaline phosphatase ,Female ,Receptors, Progesterone ,Norprogesterones - Abstract
16-Methylene-17 alpha-hydroxy-19-norpregn-4-ene-3,20-dione 1 and its 17 alpha-acylated derivatives were synthesized. The length of the 17 alpha-side-chain ranges from C2-C6. As anticipated, compound 1 did not show any progestational activity or receptor binding activity; whereas, the acylated compounds, especially the butyrate, showed remarkable ability to bind to progesterone receptors. These compounds also showed progestational activity in an in vitro T47D cell culture assay in which progestins increase alkaline phosphatase activity and in an in vivo ovulation inhibition assay. All of the compounds synthesized were without estrogenic activities. The results showed that acylation of 16-methylene-17 alpha-hydroxy-19-norprogesterone can increase progestational activity. The progestational activities of these compounds varied with the 17 alpha-side chain.
- Published
- 1997
4. Nestorone: a progestin with a unique pharmacological profile
- Author
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Yun-Yen Tsong, Narender Kumar, Kalyan Sundaram, and Samuel S. Koide
- Subjects
Male ,Ovulation ,medicine.medical_specialty ,Receptors, Steroid ,medicine.drug_class ,Clinical Biochemistry ,Estrogen receptor ,Biology ,Biochemistry ,Binding, Competitive ,Pregnancy Maintenance ,Rats, Sprague-Dawley ,Endometrium ,Endocrinology ,Sex hormone-binding globulin ,Receptors, Glucocorticoid ,Pregnancy ,Internal medicine ,medicine ,Contraceptive Agents, Female ,Animals ,Levonorgestrel ,Testosterone ,Molecular Biology ,Pharmacology ,Dose-Response Relationship, Drug ,Progesterone Congeners ,Organic Chemistry ,Prostate ,Organ Size ,Rats ,Hormone receptor ,Receptors, Androgen ,biology.protein ,Ovariectomized rat ,Segesterone acetate ,Female ,Rabbits ,Receptors, Progesterone ,Progestin ,hormones, hormone substitutes, and hormone antagonists ,Norprogesterones ,medicine.drug ,Protein Binding - Abstract
Nestorone(R) (Nestorone 16-methylene-17alpha-acetoxy-19-norpregn-4-ene-3,20-dione), formerly referred to as ST 1435, is a potent progestin when given parenterally via sustained release formulations. The pharmacological profile of Nestorone was compared with that of levonorgestrel and 3-keto-desogestrel by steroid receptor binding studies and by in vivo bioassays in rats and rabbits. 3-Keto-desogestrel showed the highest binding affinity to progesterone receptors (PR) followed by Nestorone, levonorgestrel, and progesterone. The binding affinity of Nestorone to androgen receptors (AR) was 500- to 600-fold less than that of testosterone. However, both levonorgestrel and 3-keto-desogestrel showed significant binding (40 to 70% of testosterone) to AR. None of the progestins bound to estrogen receptors (ER). The progestational activity of Nestorone, levonorgestrel, and progesterone was compared using McPhail index in immature rabbits and pregnancy maintenance and ovulation inhibition tests in rats after subcutaneous (s.c.) administration. In all three tests, Nestorone was the most potent progestin. The progestational activity of Nestorone was also compared after oral and s.c. administration in rabbits. The potency of Nestorone was over 100-fold higher upon s.c. administration than via the oral route. The androgenic activity of progestins, based on the stimulation of ventral prostate (androgenic target) and levator ani (anabolic target) growth in castrated immature rats, showed good correlation with their binding affinity to AR. Nestorone showed no androgenic or anabolic activity. Nestorone did not bind to sex hormone binding globulin (SHBG), whereas both levonorgestrel and 3-keto-desogestrel showed significant binding to SHBG. The estrogenic/antiestrogenic activity of Nestorone was investigated in immature ovariectomized rats. In contrast to estradiol and levonorgestrel, Nestorone showed no uterotropic activity in ovariectomized rats. Despite significant binding to glucocorticoid receptors (GR), Nestorone showed no glucocorticoid activity in vivo. It is concluded that a strong progestational activity, combined with lack of androgenic, estrogenic, and glucocorticoid-like activities, confer special advantages to Nestorone for use in contraception and hormone replacement therapy.
- Published
- 2000
5. Synthesis and progestational activity of 16-methylene-17α-hydroxy-19-norpregn-4-ene-3,20-dione and its derivatives
- Author
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Li, Fang, primary, Kumar, Narender, additional, Tsong, Yun-Yen, additional, Monder, Carl, additional, and Bardin, C.Wayne, additional
- Published
- 1997
- Full Text
- View/download PDF
6. A study on the stability of an estrogem-protein conjugate in vivo and under in vitro conditions
- Author
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Yun-Yen Tsong and Shohei Koide
- Subjects
medicine.medical_treatment ,Clinical Biochemistry ,Uterus ,Receptors, Cell Surface ,Tritium ,Biochemistry ,Steroid ,Endocrinology ,Drug Stability ,In vivo ,medicine ,Animals ,Castration ,Bovine serum albumin ,Molecular Biology ,Pharmacology ,Chromatography ,Estradiol ,biology ,Chemistry ,Ovary ,Organic Chemistry ,Serum Albumin, Bovine ,Succinates ,In vitro ,Rats ,medicine.anatomical_structure ,biology.protein ,Ovariectomized rat ,Female ,Specific activity ,Protein Binding ,Subcellular Fractions ,Conjugate - Abstract
[3 H] Estradiol-17β-succinyl bovine serum albumin conjugate ([3H]-E2-BSA) was synthesized with a specific activity of 1.92 × 107 cts/min/mg. The conjugate was administered iv to ovariectomized rats and the quantity of free [3H] steroid in the uterus was determined. Radioactive material was detected in all of the subcellular fractions of the uterus and identified as estradlol-17β. Similar subcellular distribution of the radioactivity was observed when [3H]E2-BSA was added in vitro to uterine homogenate. Free estradlo1-17β was released when the conjugate was Incubated with rat uterine homogenate or with serum. The results of the present study suggest that E2-BSA is hydrolyzed in vivo and under in vitro conditions. It is recommended that the stability of a hormone-protein conjugate be established before use.
- Published
- 1974
7. Nestorone®: clinical applications for contraception and HRT
- Author
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Sitruk-Ware, Regine, Small, Margaret, Kumar, Narender, Tsong, Yun-Yen, Sundaram, Kalyan, and Jackanicz, Theodore
- Subjects
- *
PROGESTERONE , *STEROIDS , *PREGNANCY , *HORMONE therapy - Abstract
The 19-nor derivatives of progesterone are referred to as “pure” progestational molecules as they bind almost exclusively to the progesterone receptor (PR) without interfering with receptors of other steroids. In this category is Nestorone®, which has strong progestational activity and antiovulatory potency with no androgenic or estrogenic activity in vivo. These properties make it highly suitable for use in contraception and hormonal therapy (HT). Due to its high potency, very low doses of Nestorone may be delivered via long-term sustained-release delivery systems. Nestorone, 75 or 100 μg per day, released by vaginal ring has suppressed ovulation in women, with inhibition of follicular maturation. A vaginal ring releasing both 150 μg of Nestorone and 15 μg of ethinyl estradiol per day has effectively suppressed ovulation for 13 consecutive cycles. Nestorone has also been used effectively in a single implant for contraception in breastfeeding women and shows promise for use in transdermal systems as a contraceptive or for HT when combined with estrogen. [Copyright &y& Elsevier]
- Published
- 2003
- Full Text
- View/download PDF
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