science

Testolactone

Testolactone is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Testolactone rather than just read about it. In short: Testolactone (INNTooltip International Nonproprietary Name, USANTooltip United States Adopted Name) (brand name Teslac) is a non-selective, irreversible, steroidal aromatase inhibitor which is used as an antineoplastic drug to treat advanced-stage breast cancer. The drug was discontinued in 2008 and is no longer available for medical use.

Key takeaways

Testolactone belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Testolactone to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Testolactone from memory before moving on to harder problems.

Reference excerpt

Testolactone (INNTooltip International Nonproprietary Name, USANTooltip United States Adopted Name) (brand name Teslac) is a non-selective, irreversible, steroidal aromatase inhibitor which is used as an antineoplastic drug to treat advanced-stage breast cancer. The drug was discontinued in 2008 and is no longer available for medical use.

Medical uses Testolactone is mainly used for treating various types of breast cancer in women who have been through menopause or whose ovaries no longer function. It works by blocking the production of estrogens, which helps prevent the growth of breast cancers that are stimulated by estrogens. It may also prevent tumor cells from being activated by other hormones. Testolactone has also been used to postpone precocious puberty because of its ability to block estrogen production. In addition, it has been used in the treatment of gynecomastia. Testolactone is used to treat breast cancer at a dosage of 250 mg four times per day by mouth or 100 mg three times per week by intramuscular injection.

Available forms Testolactone has been provided in the form of 50 mg and 250 mg oral tablets.

Side effects The most common side effects include:

Abnormal skin sensations Aches of the legs and arms General body discomfort Hair loss Loss of appetite Nausea Redness of the tongue Vomiting Rare but serious side effects include:

Allergic reactions New breast lumps Bone pain Menstrual changes, abnormal vaginal bleeding, abnormal vaginal discharge, pelvic pain or pressure Excessive nausea, vomiting, or thirst Glossitis Edema Paresthesia Erythema Alopecia

Pharmacology The principal action of testolactone is reported to be inhibition of aromatase activity and the reduction in estrogen synthesis that follows. Androstenedione, a 19-carbon steroid hormone produced in the adrenal glands and the gonads, is where estrone synthesis originates and is the source of estrogen in postmenopausal women. In vitro studies report that the aromatase inhibition may be noncompetitive and irreversible, and could possibly account for the persistence of this drug's effect on estrogen synthesis after drug withdrawal. Testolactone at a dosage of 1,000 mg/day has been found to decrease estradiol levels in men by 25 to 50% after 6 to 10 days of use. This reduction is substantially less than with second- and third-generation aromatase inhibitors. In addition to its activity as an aromatase inhibitor, testolactone also reportedly possesses some anabolic activity and weak androgenic activity via binding to and activation of the androgen receptor (AR). However, its affinity for the AR is very low; in one study, it showed 0.0029% of the affinity of the anabolic steroid metribolone (100%) for the human AR (Ki = 41 μM and 1.18 nM, respectively). In accordance, androgenic side effects such as hirsutism, acne, and voice changes have been reported in no women in clinical trials with testolactone.

Chemistry Testolactone, also known as 13-hydroxy-3-oxo-13,17-secoandrosta-1,4-dien-17-oic acid δ-lactone, is a synthetic 18-oxasteroid and a D-homo-18-oxo analogue of androstenedione (androst-4-en-3,17-dione), with a six-membered lactone ring in place of the five-membered carbocyclic D-ring.

History Testolactone was first approved for medical use in the United States in 1970.

References

Illustrations

Worked examples

Example 1 — a first encounter with Testolactone

Start with the simplest possible case. Write down what Testolactone claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Testolactone before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Testolactone ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Testolactone

In research: Testolactone appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Testolactone in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Testolactone is common in secondary-school and first-year university syllabi. It links to neighbouring topics Androgens, Androstanes, Aromatase inhibitors, so understanding it makes those chapters shorter.
In everyday life: Look for Testolactone outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Testolactone in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Testolactone means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Testolactone out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Testolactone in simple terms?

Why does Testolactone matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Testolactone?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Testolactone.