F5 Steroid Hormones Lecture Note Flashcards

Comprehensive vocabulary flashcards covering steroid hormone classifications, biosynthesis, physicochemical properties, and specific therapeutic examples.

Steroid Hormones

Chemical substances used primarily in birth control, hormone-replacement therapy (HRT), inflammatory conditions, and cancer treatment.

Estrogens

One of the five general groups of steroid hormones, primarily responsible for the development of female sex characters.

Progestins

A general group of steroid hormones that include progesterone, used in oral contraceptives and to prevent habitual abortion.

Androgens

A general group of steroid hormones that include testosterone, essential for normal spermatogenesis and male secondary characteristics.

Glucocorticoids (GCs)

A group of steroid hormones, such as hydrocortisone (cortisol), involved in regulating metabolism and inflammatory responses.

Mineralocorticoids (MCs)

A group of steroid hormones, such as aldosterone, involved in maintaining salt and water balance.

Cyclopentanoperhydrophenanthrene

The basic four-ring core structure common to all steroids.

5\text{\alpha-Pregnane}

A parent steroid hydrocarbon with a structure containing $21$ carbon atoms.

5\text{\alpha-Cholestane}

A parent steroid hydrocarbon with a structure containing $27$ carbon atoms.

5\text{\alpha-Androstane}

A parent steroid hydrocarbon with a structure containing $19$ carbon atoms.

5\text{\alpha-Estrane}

A parent steroid hydrocarbon with a structure containing $18$ carbon atoms.

Cortisone

$17,21\text{-Dihydroxypregn-4-ene-3,11,20-trione}$.

Testosterone

$17\beta\text{-Hydroxyandrost-4-en-3-one}$.

$$17\beta\text{-estradiol}$$

$\text{Estra-1,3,5(10)-triene-3,17}\beta\text{-diol}$.

Steroid Biosynthesis Precursor

Cholesterol, which is synthesized in vivo from acetyl-coenzyme A (acetyl-CoA) via the mevalonate pathway.

Mevalonate pathway

The multi-step metabolic pathway used to produce cholesterol from acetyl-CoA.

$P450$ (Sidechain cleavage)

The enzyme responsible for the conversion of cholesterol into pregnenolone.

$$17\text{-hydroxylase}$$

An enzyme involved in the biosynthesis of steroid hormones, converting pregnenolone to $17\text{-Hydroxypregnenolone}$.

$$3\beta\text{-HSD}$$

3-beta-hydroxysteroid dehydrogenase, an enzyme that converts pregnenolone to progesterone.

$$21\text{-hydroxylase}$$

A key enzyme in the steroidogenic pathway that acts on progesterone/$17\text{-Hydroxyprogesterone}$ to produce precursors for cortisol and aldosterone.

$$11\beta\text{-hydroxylase}$$

The enzyme required for the final steps of hydrocortisone (cortisol) synthesis.

Aldosterone synthase

The enzyme required for the production of the mineralocorticoid aldosterone.

Aromatase

The enzyme complex responsible for converting androgens (like testosterone and androstenedione) into estrogens.

$$17,20\text{-lyase}$$

An enzyme that facilitates the conversion of $17\text{-hydroxy}$ steroids into androgens like dehydroepiandrosterone (DHEA).

$$17\beta\text{-HSD}$$

$17\beta\text{-hydroxysteroid}$ dehydrogenase, which converts androstenedione to testosterone or estrone to estradiol.

5\text{\alpha-reductase}

The enzyme that converts testosterone into the more potent androgen 5\text{\alpha-Dihydrotestosterone}.

Hydrocortisone (cortisol)

The primary life-sustaining glucocorticoid produced in the adrenal cortex.

Aldosterone

The primary mineralocorticoid produced from the steroid biosynthesis pathway.

Dehydroepiandrosterone (DHEA)

A steroid intermediate biosynthesized from $17\text{-Hydroxypregnenolone}$ via the action of $17,20\text{-lyase}$.

Androstenedione

A 19-carbon steroid intermediate that serves as a precursor to both testosterone and estrone.

Pregnenolone

The first steroid intermediate formed from cholesterol by sidechain cleavage.

Steroid Physicochemical Appearance

Most steroids are white crystalline solids existing as needles, leaflets, platelets, or amorphous particles.

Steroid Water Solubility

The compounds tend to be water insoluble; salts of these compounds are the most water soluble forms.

Sterols

Steroid derivatives where the substituent at position $17$ (R) is an aliphatic chain.

Sex hormones (Classification)

Steroids where the substituent at position $17$ (R) is a ketone or hydroxyl group; they may possess a $2\text{-carbon}$ side chain.

Cardiac glycosides (R group)

Steroid derivatives where the substituent at position $17$ (R) is a lactone ring.

Bile acids (Classification)

Steroids with a $5\text{-carbon}$ side chain ending with a carboxylic acid ($\text{-COOH}$) group.

Sapogenins (Classification)

Steroid derivatives with an oxacyclic (ethereal) ring system as the substituent at position $17$ (R).

Zoosterol

A sterol of animal origin, with cholesterol being the primary example.

Phytosterol

Sterols of plant origin, such as ergosterol and stigmasterol.

Mycosterol

Sterols of fungal origin, with ergosterol being a prominent example.

Cholesterol

The most common zoosterol and the primary precursor for steroid hormone biosynthesis in mammals.

Ergosterol

A common phytosterol or mycosterol with a double bond structure that differs slightly from cholesterol.

Stigmasterol

A specific type of phytosterol found in plants.

Gestogen

A class of sex hormones primarily exemplified by progesterone.

Bufadienolides

A type of cardiac glycoside that contains a six-membered lactone ring.

Cardenolides

A type of cardiac glycoside characterized by a five-membered lactone ring.

Cardiac glycoside components

Consists of a steroid nucleus, a sugar moiety, and a lactone moiety.

Cholic Acid (CA)

A primary bile acid synthesized in the liver.

Deoxycholic acid (DXCA)

A secondary bile acid formed by gut bacteria from cholic acid.

Lithocholic acid (LICA)

A secondary bile acid formed by gut bacteria from chenodeoxycholic acid.

Chenodeoxycholic acid (ChDxCA)

A primary bile acid that can be converted into lithocholic acid by gut bacteria.

Bile acid conjugation site

The location on the carboxylic acid side chain where glycine or taurine is added to the steroid.

Secondary bile acids

Bile acids formed from primary bile acids after removal of hydroxyl groups by gut bacteria.

Taurine

An amino acid derivative ($\text{H}_2\text{NCH}_2\text{CH}_2\text{SO}_3^-$) that conjugates with bile acids in the liver.

Sapogenins (Definition)

The aglycone or non-saccharide portions of the natural products known as saponins.

Saponins

A family of natural products that contain sapogenins as their aglycone component.

Diosgenin

A specific sapogenin that features a steroid framework and is used as a starting material for steroid synthesis.

Androgen Natural Roles

Normal spermatogenesis, development of secondary male characteristics, and growth.

Testosterone Use in Oncology

Used in the treatment of breast carcinoma (Breast CA).

Androstane nucleus

The 19-carbon steroid framework utilized by androgens like testosterone.

Estrogen Cardioprotection

One of the physiological functions of estrogens, helping to protect the heart and vascular system.

Estrogen Vasodilation

A physiological function of estrogen that causes the widening of blood vessels.

Estrogen Skeletal Function

The role of maintaining the integrity of the skeleton during a woman's reproductive age.

Estrone ($\text{E1}$)

A natural estrogen secreted by the ovary; it is the primary circulating estrogen after menopause and has $1/3$ the activity of estradiol.

Estradiol ($\text{E2}$)

Also known as $17\beta\text{-estradiol}$, it is the primary female sex hormone and principal estrogen in premenopausal women.

Estriol ($\text{E3}$)

A natural estrogen that is less potent than estradiol and is produced in significant amounts by the placenta during pregnancy.

Estradiol Menstrual Role

Important in the regulation of the menstrual cycle and stimulation of the proliferative phase of the endometrium.

Synthetic Estrogen properties

Features a long duration of action (DOA) and a slow metabolic rate compared to natural estrogens.

Ethinylestradiol

A synthetic steroidal estrogen commonly used in oral contraceptives.

Mestranol

A steroidal synthetic estrogen.

Diethylstilbestrol

A non-steroidal (NS) synthetic estrogen.

Hexestrol

A non-steroidal (NS) synthetic estrogen.

Dienestrol

A non-steroidal (NS) synthetic estrogen.

Estrogen Therapeutic Uses

Contraception, hormone replacement therapy (HRT), osteoporosis, and senile vaginitis.

Estrogen Adverse Effects

Nausea, breast tenderness, headache, edema, and hypertension.

Progesterone (Definition)

The primary natural progestational hormone.

Progesterone Use in Bleeding

Used for the treatment of functional uterine bleeding resulting from a lack of estrogen.

Habitual Abortion

A medical condition that progesterone is used to prevent.

Progesterone Diagnostic Use

Used as a tool for pregnancy diagnosis.

Progesterone Oncology Use

Used in the treatment of advanced carcinoma in the breast.

Progesterone Breast Discomfort

Indicated for the treatment of premature discomfort in the breast.

Progesterone Body Integrity

Plays a role in maintaining skin elasticity and bone strength.

Estratriol ($\text{E3}$) Synthesis

Synthesized from estradiol through further hydroxylation steps.

A-ring Aromatization

The process by which the A-ring of androstenedione or testosterone is made aromatic to form estrone or estradiol.

$$17\text{-Hydroxypregnenolone}$$

The metabolic intermediate between pregnenolone and dehydroepiandrosterone (DHEA).

Ursodeoxycholic acid

A specific type of bile acid shown in the secondary bile acid pathway.

Glycine conjugation

The liver process of adding a glycine molecule ($\text{H}_2\text{NCH}_2\text{COOH}$) to a bile acid.

ChDxCA to LICA Conversion

The bacterial conversion of chenodeoxycholic acid to lithocholic acid in the gut.

Estrone Potency

Demonstrates approximately $1/3$ of the estrogenic activity of estradiol.