Steroidal Hormones and Testosterone
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Questions and Answers

Which enzyme is responsible for the conversion of testosterone to 5a-dihydrotestosterone (DHT)?

  • 5a-Reductase (correct)
  • Aromatase
  • 17b-Hydroxysteroid Dehydrogenase
  • None of the above

DHT is a less potent androgen than testosterone.

False (B)

What is the name of the most potent endogenous androgen?

5a-dihydrotestosterone (DHT)

The conversion of testosterone to 5a-dihydrotestosterone (DHT) is catalyzed by the ______ enzyme.

<p>5a-Reductase</p> Signup and view all the answers

Match the following terms with their corresponding descriptions:

<p>Testosterone = The most potent endogenous androgen 5a-Reductase = Enzyme responsible for the conversion of testosterone to DHT DHT = Important metabolite of testosterone</p> Signup and view all the answers

What is testosterone classified as?

<p>Prohormone (B)</p> Signup and view all the answers

Testosterone can be taken orally and is effective in that form.

<p>False (B)</p> Signup and view all the answers

What is one benefit of using ester derivatives of testosterone?

<p>Long duration of action</p> Signup and view all the answers

Testosterone is classified as a ______ hormone.

<p>prohormone</p> Signup and view all the answers

Match the following terms with their descriptions:

<p>Testosterone = A male sex hormone Ester derivatives = Forms that improve duration of action Oral administration = Ineffective method for testosterone Prohormone = Precursor to an active hormone</p> Signup and view all the answers

What type of activity is methenolone primarily known for?

<p>Anabolic activity (B)</p> Signup and view all the answers

Methenolone contains 17a-CH3.

<p>False (B)</p> Signup and view all the answers

How is methenolone typically administered for its anabolic action?

<p>IM or deep cutaneous injection</p> Signup and view all the answers

Methenolone is used orally and has potent ______ activity.

<p>anabolic</p> Signup and view all the answers

Match the following terms related to methenolone:

<p>Administration = IM or deep cutaneous injection Anabolic activity = Potent 17a-CH3 = Absent Usage = Orally</p> Signup and view all the answers

What is the primary use of Stanozolol?

<p>Anabolic agent (A)</p> Signup and view all the answers

Stanozolol has three times the anabolic activity of 17a-methyltestosterone.

<p>True (A)</p> Signup and view all the answers

What type of compound is Stanozolol?

<p>Heterocyclic compound</p> Signup and view all the answers

Stanozolol has slight ________ activity.

<p>androgenic</p> Signup and view all the answers

Match the following properties with Stanozolol:

<p>Anabolic activity = Three times that of 17a-methyltestosterone Androgenic activity = Slight Compound type = Heterocyclic Primary use = Anabolic agent</p> Signup and view all the answers

What is a characteristic of 17a-Methyltestosterone?

<p>It is a derivative of testosterone (C)</p> Signup and view all the answers

5a-Dihydrotestosterone (5a-DHT) is not a metabolite of testosterone.

<p>False (B)</p> Signup and view all the answers

What type of activity does 17a-Methyltestosterone have?

<p>Androgenic and anabolic activity</p> Signup and view all the answers

17a-Methyltestosterone is an __________ active derivative.

<p>orally</p> Signup and view all the answers

What is the primary function of testosterone in the body?

<p>Promotes muscle growth and development (A)</p> Signup and view all the answers

Synthetic anabolic androgenic steroids are naturally occurring hormones.

<p>False (B)</p> Signup and view all the answers

Name one commonly available 17b-ester for IM injection.

<p>Testosterone enanthate</p> Signup and view all the answers

The primary effect of testosterone is to promote __________ and development in males.

<p>muscle growth</p> Signup and view all the answers

Match the following 17b-esters with their characteristics:

<p>Testosterone enanthate = Long-acting IM injection Testosterone cypionate = Commonly used in the U.S. Testosterone propionate = Short-acting IM injection Testosterone undecanoate = Oral and injectable form</p> Signup and view all the answers

Flashcards

5a-dihydrotestosterone (DHT)

An important metabolite of testosterone, more potent than testosterone itself.

5a-Reductase

An enzyme that converts testosterone into DHT.

Endogenous androgen

Naturally occurring male hormone produced in the body.

Potency of DHT

DHT is considered the most potent form of androgen.

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Role of testosterone

Testosterone is a key hormone in male development and health.

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Testosterone

A hormone responsible for male traits and reproductive activity.

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Synthetic anabolic steroids

Artificial substances that mimic testosterone to promote muscle growth.

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IM injection

Intramuscular injection, a method to deliver substances directly into muscles.

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v 17b-Esters

A form of testosterone modification for prolonged release in the body.

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Androgenic effects

Effects related to male characteristics, like facial hair and deeper voice.

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Testosterone Metabolism

The biochemical process that converts testosterone into various metabolites, including 5a-DHT.

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5a-Dihydrotestosterone (5a-DHT)

A potent androgen derived from testosterone with significant biological activity.

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Synthetic Androgens

Man-made derivatives of testosterone designed for various medical and performance purposes.

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17a-Methyltestosterone

An orally active synthetic androgen with similar effects to testosterone.

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Anabolic Activity

The process of building up organs and tissues, sometimes associated with muscle growth.

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Methenolone

An anabolic steroid with potent anabolic activity, used orally.

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17a-CH3

A methyl group commonly found in many anabolic steroids to enhance effectiveness.

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Depot Preparation

A method of drug administration, often through injection, that allows slow release over time.

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Oral Administration

Taking medication by mouth for absorption in the digestive system.

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Prohormone

A substance that is converted into a hormone in the body.

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Testosterone Esters

Derivatives of testosterone that have a longer duration of action.

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Oral Inactivity

Testosterone is inactive when taken orally.

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Ester Derivatives

Chemical modifications of testosterone for prolonged effects.

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Stanozolol

An anabolic agent with three times the anabolic activity of 17a-methyltestosterone.

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Androgenic activity

The effect of a compound on the development of male characteristics.

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Heterocyclic compound

A compound consisting of a ring structure that contains atoms of at least two different elements.

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Study Notes

Steroidal Hormones

  • Steroidal hormones include male sex hormones, also known as androgens.
  • Androgens control the development of male sex characteristics, including sperm production (spermatogenesis), growth of sex organs (prostate, seminal vesicles), and metabolic effects during adolescence.
  • Androgens cause nitrogen retention by stimulating protein synthesis (anabolic effect).
  • They decrease the rate of protein catabolism.
  • Testosterone is the major natural and androgenic hormone.

Active Form of Testosterone

  • The important metabolite of testosterone is 5α-dihydrotestosterone (DHT).
  • DHT is formed from testosterone by the action of 5α-reductase enzyme.
  • DHT is considered the most potent endogenous androgen.
  • Testosterone is a prohormone.

Testosterone Esters

  • Other natural steroids, like testosterone, are inactive orally.
  • Long-duration of action can be obtained by using ester derivatives.
  • Esterification of testosterone with acids (cyclopentylpropionate or undecanoate at the 17β-position) results in agents with increased duration of action when administered intramuscularly (IM).

Metabolism of Testosterone and 5α-Dihydrotestosterone (5α-DHT)

  • Metabolites conjugates are also formed.
  • Testosterone is converted to DHT.
  • 5α-Reductase is the key enzyme.
  • Metabolism results in various products, including androstenedione, 5α-androstane-3,17-diol, epiandrosterone, and etiocholanolone.

Synthetic Androgens and Anabolic Agents

  • 17α-methyltestosterone is an orally active derivative with androgenic and anabolic activity.
  • Increasing the length of the 17α-alkyl side chain of testosterone decreases activity, and the incorporation of a 17α-ethynyl group creates compounds with pregestational activities.
  • It is important to separate androgenic activity from anabolic activity in testosterone derivatives.
  • Development of anabolic agents with reduced or no androgenic activity is desirable.

Specific Anabolic Steroids

  • Oxandrolone is a heterocyclic analog of 17-methyltestosterone which contains a lactone in ring A and is susceptible to hydrolysis.
  • Oxandrolone has three times the anabolic activity of 17α-methyltestosterone with slight androgenic activity.
  • Stanozolol is another heterocyclic compound used for its anabolic activity.

17β-Testosterone Acetate Derivatives as Anabolic Agents

  • Alkylation in the C1 position of the androstane molecule generally increases anabolic activity.
  • Methenolone, although lacking 17α-CH3, has potent anabolic activity and is used orally.
  • Methenolone in ester form (e.g., acetate or enanthate) is used for its anabolic action via intramuscular (IM) or deep cutaneous injection as a depot preparation.

19-Norandrogens

  • Removal of the 19-methyl group creates 19-norandrogens with more favorable anabolic-to-androgenic activity.
  • Nandrolone has a 4:1 anabolic-to-androgenic ratio.
  • Nandrolone decanoate is a long-acting ester for deep intramuscular injection, notably in treating anemia with renal insufficiency.

Abuse of Steroidal Anabolic Agents

  • The use of anabolic steroids by athletes started in the late 1940s and is widespread.
  • The FDA issued an alert in late 1987 about the risks of anabolic steroid abuse.
  • Side effects include increased risk of coronary heart disease, stroke, obstructed blood vessels, increased aggression, liver tumors, jaundice, testicular atrophy, enlarged prostate, decreased sperm count, breast enlargement, impotence, beard growth, baldness, deepened voice, and breast diminution, in men and women.

Antiandrogenic Agents

  • Antiandrogens block androgen receptors or inhibit androgen biosynthesis.
  • Competitive antiandrogens block androgen receptors (e.g., cyproterone acetate).
  • Nonsteroidal competitive antagonists block androgen receptors (e.g., flutamide).
  • 5α-Reductase inhibitors reduce the conversion of testosterone to DHT (e.g., finasteride, dutasteride).

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Description

This quiz explores steroidal hormones, particularly androgens and their effects on male sex characteristics and metabolism. It also examines the active form of testosterone, its metabolites, and the role of testosterone esters. Test your understanding of these key concepts in hormonal biology.

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