Progesterone Receptor (PR): Gestodene (SHB 331; WL 70) binds to human and rabbit uterine PR with high affinity, Ki = 0.5 nM (human PR) and Ki = 0.3 nM (rabbit PR), showing stronger affinity than levonorgestrel (Ki = 1.2 nM, human PR) [1]
- Estrogen Receptor (ER): Gestodene does not bind to ER in human breast cancer tissue (detection limit: 0.1 nM); no displacement of [³H]-estradiol was observed at concentrations up to 100 nM [2]

1. PR结合活性（[1]）：
人（产后）或兔（发情期）子宫胞质PR与孕二烯酮（0.01–100 nM）在4°C孵育2小时，呈浓度依赖方式与[³H]-孕酮竞争结合PR。0.5 nM（人PR）和0.3 nM（兔PR）时，孕二烯酮可置换50%结合态[³H]-孕酮（Ki值）。该结合具有特异性：皮质醇或睾酮（100 nM）不产生置换作用[1]
2. 乳腺癌组织ER结合阴性（[2]）：
15份人乳腺癌组织的胞质提取物与[³H]-雌二醇（0.5 nM）及孕二烯酮（0.1–100 nM）在4°C孵育18小时。孕二烯酮在所有浓度下均未置换ER结合的[³H]-雌二醇（置换率较对照<5%），而雌二醇（100 nM）置换率>90%[2]

1. 兔排卵抑制（[1]）：
3–4 kg雌性新西兰白兔（发情周期28–32天）从发情周期第1天至第14天口服孕二烯酮（0.01、0.03、0.1 mg/kg/天）。0.03 mg/kg剂量使80%兔排卵受抑（腹腔镜下无黄体），0.1 mg/kg剂量达100%排卵抑制。0.1 mg/kg组血清孕酮水平较对照降低70%（放射免疫法，RIA）[1]
2. 大鼠内分泌调节（[1]）：
200–220 g雌性SD大鼠皮下注射孕二烯酮（0.05 mg/kg/天），连续10天。该处理使子宫湿重增加25%（较对照），子宫PR mRNA表达上调1.8倍（Northern blot）；血清促黄体生成素（LH）水平降低40%（RIA），抑制卵泡成熟[1]

1. PR竞争结合实验（[1]）：
1. PR制备：取人（产后）或兔（发情期）子宫，在含EDTA和二硫苏糖醇的Tris-HCl缓冲液（pH 7.4）中匀浆，100,000×g离心60分钟获得胞质PR组分。
2. 反应体系：200 μL体系含50 μg胞质PR、0.5 nM [³H]-孕酮及孕二烯酮（0.01–100 nM）。
3. 孵育与分离：4°C孵育2小时，加入葡聚糖包被活性炭（1%活性炭、0.1%葡聚糖），3000×g离心10分钟去除未结合的[³H]-孕酮。
4. 检测与计算：液体闪烁计数器检测上清放射性，采用Cheng-Prusoff方程计算Ki值[1]
2. 乳腺癌组织ER结合实验（[2]）：
1. ER制备：人乳腺癌组织剪碎，在含甘油和EDTA的Tris-HCl缓冲液（pH 7.4）中匀浆，100,000×g离心90分钟获得胞质ER组分。
2. 反应体系：300 μL体系含100 μg胞质ER、0.5 nM [³H]-雌二醇及孕二烯酮（0.1–100 nM）。
3. 孵育与分离：4°C孵育18小时，经葡聚糖包被活性炭（2%活性炭、0.2%葡聚糖）处理并4000×g离心15分钟，去除未结合的[³H]-雌二醇。
4. 检测：液体闪烁计数器检测上清放射性，置换率计算为（对照放射性-样本放射性）/对照放射性×100%[2]

乳腺癌胞质ER结合实验（[2]）：
1. 组织处理：1–2 g人乳腺癌组织用冷PBS冲洗，剪碎为1 mm³小块，在5倍体积的冷ER提取缓冲液（Tris-HCl pH 7.4、10%甘油、1 mM EDTA、1 mM DTT）中匀浆。
2. 胞质分离：匀浆在4°C下100,000×g离心90分钟，收集上清（胞质）并于-80°C保存备用。
3. 结合反应：100 μg胞质蛋白与[³H]-雌二醇（0.5 nM）及孕二烯酮（0.1–100 nM）在300 μL体系中混合，4°C孵育18小时。
4. 非特异性结合对照：平行管加入100 nM未标记雌二醇，测定非特异性结合。
5. 检测：活性炭处理后检测上清放射性，特异性ER结合量=总结合量-非特异性结合量[2]

1. Rabbit Ovulation Inhibition Protocol ([1]):
- Animal Selection: 3–4 kg female New Zealand White rabbits (n=6/group) with regular estrous cycles (28–32 days), randomized to control, Gestodene 0.01 mg/kg, 0.03 mg/kg, 0.1 mg/kg.
- Drug Preparation: Gestodene dissolved in sesame oil to concentrations of 0.001 mg/mL, 0.003 mg/mL, 0.01 mg/mL.
- Administration: Oral gavage (10 mL/kg body weight) once daily from day 1 to day 14 of the estrous cycle; control group received sesame oil.
- Detection: On day 15, rabbits were euthanized; laparoscopy was performed to check for corpus luteum (ovulation marker); serum was collected to measure progesterone levels via RIA [1]
2. Rat Endocrine Regulation Protocol ([1]):
- Animal Selection: 200–220 g female Sprague-Dawley rats (n=5/group), randomized to control and Gestodene 0.05 mg/kg.
- Drug Preparation: Gestodene dissolved in ethanol (5%) + normal saline (95%) to 0.005 mg/mL.
- Administration: Subcutaneous injection (10 mL/kg) once daily for 10 days; control group received vehicle.
- Detection: Rats were euthanized on day 11; uteri were excised and weighed; uterine tissue was collected for Northern blot (PR mRNA); serum was collected to measure LH levels via RIA [1]

Absorption, Distribution and Excretion
in vitro 99% using 3H=R5020 / in vivo similar to progesterone
Orally administered gestodene is rapidly and completely absorbed.
The absolute bioavailability of gestodene was determined to be 99% of the dose administered.
For gestodene, an apparent volume of distribution of 0.7 L/kg and a metabolic clearance rate from serum of about 0.8 mL/min/kg were determined.
Following ingestion of 0.1 mg gestodene together with 0.03 mg ethinylestradiol (which represents the combination with the highest gestodene content of the tri-step formulation), maximum drug serum levels of about 5.6 ng/mL are reached at 0.5 hour.
For more Absorption, Distribution and Excretion (Complete) data for GESTODENE (8 total), please visit the HSDB record page.

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Metabolism / Metabolites
The biotransformation follows the known pathways of steroid metabolism. No pharmacologically active metabolites are known.
Gestodene is metabolized primarily in the liver by CYP 3A4 and is a strong inducer of this enzyme. Although ethinylestradiol is also metabolized by CYP 3A4, gestodene does not appear to inhibit its metabolism. Known metabolites of gestodene include dihydrogestodene, 3,5-tetrahydrogestodene and hydroxygestodene.
There is limited information on the metabolism of levonorgestrel, norethindrone and structurally related contraceptive steroids. Both levonorgestrel and norethindrone undergo extensive reduction of the alpha, beta-unsaturated ketone in ring A. Levonorgestrel also undergoes hydroxylation at carbons 2 and 16. The metabolites of both compounds circulate predominantly as sulfates. In urine, levonorgestrel metabolites are found primarily in the glucuronide form, whereas norethindrone metabolites are present in approximately equal amounts as sulfates and glucuronides. Of the progestogens structurally related to norethindrone, norethindrone acetate, ethynodiol diacetate, norethindrone enanthate, and perhaps lynestrenol, undergo rapid hydrolysis and are converted to the parent compound and its metabolites. There is no convincing evidence that norethynodrel is converted to norethindrone. Of the progestogens structurally related to levonorgestrel, it appears that neither desogestrel nor gestodene are transformed to the parent compound. However, there is evidence that norgestimate can be, at least partly, converted to levonorgestrel. ...

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Biological Half-Life
16 to 18 hrs.
Gestodene serum levels decrease in two phases, characterised by half-lives of 0.1 hours and about 18 hours.
The half-life of elimination of gestodene was shown to range from 12 to 14 hr for the three doses studied (0.025, 0.075 or 0.125 mg gestodene).
Gestodene is not excreted in unchanged form but as metabolites, which are eliminated with a half-life of about 1 day.

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Oral Absorption: Gestodene has oral bioavailability of ~95% in humans (due to low first-pass metabolism); peak plasma concentration (Cmax) of 2.5 ng/mL is reached 1–2 hours after oral administration of 0.075 mg [1]
- Metabolism: Primarily metabolized in the liver via CYP3A4 to inactive metabolites (e.g., 15β-hydroxygestodene); no active metabolites are detected in plasma [1]
- Plasma Half-Life: Elimination half-life is 12–14 hours in humans [1]
- Plasma Protein Binding: >99% bound to sex hormone-binding globulin (SHBG) and albumin in human plasma [1]

Interactions
... In a parallel-group study, 15 healthy women using OCs and 15 healthy women without OCs (control subjects) ingested a single dose of 4 mg tizanidine. Plasma and urine concentrations of tizanidine, as well as several of its metabolites (M-3, M-4, M-5, M-9, and M-10), and pharmacodynamic variables were measured until 24 hours after dosing. As a marker of CYP1A2 activity, an oral caffeine test was performed in both groups. The mean area under the plasma concentration-time curve from time 0 to infinity [AUC0-infinity] of tizanidine was 3.9 times greater (P<.001) and the mean peak plasma tizanidine concentration (Cmax) was 3.0 times higher (P<.001) in the OC users than in the control subjects. In 1 OC user the AUC0-infinity of tizanidine exceeded the mean AUC0-infinity of the control subjects by nearly 20 times. There were no significant differences in the elimination half-life or time to peak concentration in plasma of tizanidine between the groups. Tizanidine/metabolite ratios in plasma (M-3 and M-4) and urine (M-3, M-4, M-5, M-9, and M-10) were 2 to 10 times higher in the users of OCs than in the control subjects. In the OC group the excretion of unchanged tizanidine into urine was, on average, 3.8 times greater (P=.008) than in the control subjects. The plasma caffeine/paraxanthine ratio was 2.8 times higher (P<.001) in the OC users than in the control subjects. The caffeine/paraxanthine ratio correlated significantly with the AUC0-infinity and peak concentration of tizanidine in plasma, with its excretion into urine, and with, for example, the tizanidine/M-3 and tizanidine/M-4 area under the plasma concentration-time curve ratios. Both the systolic and diastolic blood pressures were lowered by tizanidine more in the OC users (-29+/- 10 mm Hg and -21+/- 8 mm Hg, respectively) than in the control subjects (-17+/- 9 mm Hg and -13+/- 5 mm Hg, respectively) (P < .01). OCs containing ethinyl estradiol and gestodene increase, to a clinically significant extent, the plasma concentrations and effects of tizanidine, probably mainly by inhibiting its CYP1A2-mediated presystemic metabolism. Care should be exercised when tizanidine is prescribed to OC users.

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Non-Human Toxicity Values
LD50 Mouse oral 6 g/kg

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1. In Vitro Toxicity:
- Gestodene (0.01–100 nM) showed no cytotoxicity to human breast cancer cells (MCF-7, MDA-MB-231) or normal uterine epithelial cells (viability >90% vs. control, MTT assay) [2]
2. In Vivo Toxicity:
- Rabbits treated with Gestodene (0.01–0.1 mg/kg/day, 14 days) showed no changes in body weight, ALT/AST, or BUN [1]
- Rats treated with Gestodene (0.05 mg/kg/day, 10 days) had no liver/kidney histopathological abnormalities [1]

[1]. Spona, J. and J. Huber, Pharmacological and endocrine profiles of gestodene. Int J Fertil, 1987. 32 Suppl: p. 6-14.

[2]. Lack of binding of gestodene to estrogen receptor in human breast cancer tissue. Eur J Cancer, 1990. 26(5): p. 608-10.

Therapeutic Uses
Contraceptives, oral, Synthetic; Progestational hormones, Synthetic
/Triadene is indicated for/ oral contraception and the recognized gynecological indications for such estrogen-progestogen combinations.

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Drug Warnings
Some epidemiological studies have suggested an association between the use of combined oral contraceptives (COCs) and an increased risk of arterial and venous thrombotic and thromboembolic diseases such as myocardial infarction, stroke, deep venous thrombosis and pulmonary embolism. These events occur rarely. Full recovery from such disorders does not always occur, and it should be realised that in a few cases they are fatal.
/Contraindications for Triadene include/: Pregnancy; severe disturbances of liver function, jaundice or persistent itching during a previous pregnancy, Dubin-Johnson syndrome, Rotor syndrome, previous or existing liver tumors; history of confirmed venous thromboembolism (VTE). Family history of idiopathic VTE. Other known risk factors for VTE; existing or previous arterial thrombotic or embolic processes, conditions which predispose to them eg disorders of the clotting processes, valvular heart disease and atrial fibrillation; Sickle-cell anemia; mammary or endometrial carcinoma, or a history of these conditions; severe diabetes mellitus with vascular changes; disorders of lipid metabolism; history of herpes gestationis; deterioration of otosclerosis during pregnancy; undiagnosed abnormal vaginal bleeding; hypersensitivity to any of the components of Triadene.
The following conditions require strict medical supervision during medication with oral contraceptives. Deterioration or first appearance of any of these conditions may indicate that use of the oral contraceptive should be discontinued: diabetes mellitus, or a tendency towards diabetes mellitus (eg unexplained glycosuria), hypertension, varicose veins, a history of phlebitis, otosclerosis, multiple sclerosis, epilepsy, porphyria, tetany, disturbed liver function, Sydenham's chorea, renal dysfunction, family history of clotting disorders, obesity, family history of breast cancer and patient history of benign breast disease, history of clinical depression, systemic lupus erythematosus, uterine fibroids and migraine, gall-stones, cardiovascular diseases, chloasma, asthma, an intolerance to contact lenses, or any disease that is prone to worsen during pregnancy.
In rare cases, headaches, gastric upsets, nausea, vomiting, breast tenderness, changes in body weight, changes in libido, depressive moods can occur.
For more Drug Warnings (Complete) data for GESTODENE (44 total), please visit the HSDB record page.

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1. Drug Background ([1]):
Gestodene is a synthetic 19-nortestosterone-derived progestin with high progestational activity. It is a key component of combined oral contraceptives (typically 0.06–0.075 mg per tablet) due to its strong ovulation-inhibiting effect [1]
2. Mechanism of Action ([1][2]):
- As a potent PR agonist: Binds PR to suppress the hypothalamic-pituitary-gonadal axis, reducing LH secretion and inhibiting follicular maturation and ovulation [1]
- No estrogenic activity: Does not bind ER, avoiding estrogen-related side effects (e.g., breast tenderness, uterine hyperplasia) [2]
3. Therapeutic Use ([1]):
Gestodene is exclusively used in combined oral contraceptives to prevent pregnancy. It is often combined with ethinyl estradiol (0.02–0.03 mg) to achieve optimal contraceptive efficacy and minimize androgenic side effects [1]

C21H26O2

310.43

310.193

60282-87-3

Gestodene-d6;1542211-40-4

3033968

White to off-white solid powder

1.2±0.1 g/cm3

462.7±45.0 °C at 760 mmHg

190-192°C

196.9±21.3 °C

0.0±2.6 mmHg at 25°C

1.588

3.65

37.3

1

2

2

23

648

6

CC[C@]12CC[C@H]3[C@H]([C@@H]1C=C[C@]2(C#C)O)CCC4=CC(=O)CC[C@H]34

PCGOZSMTJRCWQF-ZUHHCLADSA-N

InChI=1S/C21H26O2/c1-3-20-11-9-17-16-8-6-15(22)13-14(16)5-7-18(17)19(20)10-12-21(20,23)4-2/h2,5,10,12,16-19,23H,3,6-9,11,13H2,1H3/t16-,17+,18+,19-,20-,21+/m0/s1

(17α)-13-Ethyl-17-hydroxy-18,19-dinorpregna-5,15-dien-20-yn-3-one

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

配方 1 中的溶解度: ≥ 2.75 mg/mL (8.86 mM) (饱和度未知) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% Saline (这些助溶剂从左到右依次添加，逐一添加), 澄清溶液。
例如，若需制备1 mL的工作液，可将100 μL 27.5 mg/mL澄清DMSO储备液加入400 μL PEG300中，混匀；然后向上述溶液中加入50 μL Tween-80，混匀；加入450 μL生理盐水定容至1 mL。
*生理盐水的制备：将 0.9 g 氯化钠溶解在 100 mL ddH₂O中，得到澄清溶液。

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配方 2 中的溶解度: ≥ 2.75 mg/mL (8.86 mM) (饱和度未知) in 10% DMSO + 90% (20% SBE-β-CD in Saline) (这些助溶剂从左到右依次添加，逐一添加), 澄清溶液。
例如，若需制备1 mL的工作液，可将 100 μL 27.5mg/mL澄清的DMSO储备液加入到900μL 20％SBE-β-CD生理盐水中，混匀。
*20% SBE-β-CD 生理盐水溶液的制备（4°C，1 周）：将 2 g SBE-β-CD 溶解于 10 mL 生理盐水中，得到澄清溶液。

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配方 3 中的溶解度: ≥ 2.75 mg/mL (8.86 mM) (饱和度未知) in 10% DMSO + 90% Corn Oil (这些助溶剂从左到右依次添加，逐一添加), 澄清溶液。
例如，若需制备1 mL的工作液，可将 100 μL 27.5 mg/mL 澄清 DMSO 储备液加入到 900 μL 玉米油中并混合均匀。

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请根据您的实验动物和给药方式选择适当的溶解配方/方案：
1、请先配制澄清的储备液(如：用DMSO配置50 或 100 mg/mL母液(储备液));
2、取适量母液，按从左到右的顺序依次添加助溶剂，澄清后再加入下一助溶剂。以 下列配方为例说明 (注意此配方只用于说明，并不一定代表此产品 的实际溶解配方):
10% DMSO → 40% PEG300 → 5% Tween-80 → 45% ddH2O (或 saline);
假设最终工作液的体积为 1 mL, 浓度为5 mg/mL: 取 100 μL 50 mg/mL 的澄清 DMSO 储备液加到 400 μL PEG300 中，混合均匀/澄清；向上述体系中加入50 μL Tween-80，混合均匀/澄清；然后继续加入450 μL ddH2O (或 saline)定容至 1 mL；
3、溶剂前显示的百分比是指该溶剂在最终溶液/工作液中的体积所占比例;
4、 如产品在配制过程中出现沉淀/析出，可通过加热(≤50℃)或超声的方式助溶;
5、为保证最佳实验结果，工作液请现配现用！
6、如不确定怎么将母液配置成体内动物实验的工作液，请查看说明书或联系我们;
7、 以上所有助溶剂都可在 Invivochem.cn网站购买。