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Steroidal Drugs
By
Dr. N.C. Baruah
Chemistry of Steroids
• Steroids are tetra cyclic compounds.
• Steroids are derivatives of Cyclopentanoperhydrophenanthrene.
• The phenanthrene and the cyclopentane ring is fused in steroids,
• The ring system is completely saturated (hydrogenated) and is referred to as a cyclopentanoperhydrophenanthrene.
• Steroids on dehydrogenation with selenium at 360°C gives Diel’s hydrocarbon
• (17-methylcyclopentanoperhydrophenanthrenes)
Classification of steroids
• The steroids are classified as Estrane, Androstane, Pregnane and Cholestane.
• All other steroids are the derivatives of these classes.
Estrane (C18) Androstane (C19)
Classification
• Pregnane (C21) Cholestane (C27)
Nomenclature of steroids
• The numbering of the carbon atoms in steroids remain
fixed.
• If a carbon is absent in its position the rest of the
numbering remain unchanged. ‘Nor’ is used to indicate
absence of methylene gr. or terminal methyl group.
• A solid line denotes a group above the plane is β-
configuration, dotted line denotes below the plane (α-
configuration)
Nomenclature of steroids
• If there is any double bond in the steroid structure,
– The suffix ‘-ane’ of the parent name
– is replaced with
– ‘-ene’ if one double bond is present,
– ‘-diene’ if two double bonds are present,
– ‘-triene’ if three double bonds are present, and so forth.
Major classes of natural steroids • Hormones produced by gonads:
• Testosterone (androgenic & anabolic)(C 19)
• Estrogens(C 18)
• Progestogens (C 21)
• Hormones produced by adrenal gland:-
• Cortisol (glucocorticoids),
• Aldosterone (mineralocorticoids),
• Bile acids and salts of Cholic acids,
• Sterols – Cholesterol, Ergosterol, Stigmasterol.
Hormones produced by gonads
Estradiol Estrone
• Testosterone Progesterone
Hormones produced by adrenal gland
• Cortisol
• Aldosterone
Bile acids and salts-bile acids
• Cholic acid
Deoxycholic acid
• Chenodeoxycholic acid
Cholesterol
.
Biosynthesis of steroids
• Estrogens are biosynthesized from cholesterol in the ovary.
• During pregnancy, the placenta begins to synthesize estrogen.
• Progesterone is biosynthesized in corpus luteum.
• Estrogens and progesterone are the two most important female sex hormones.
Biosynthesis of steroids
• Testosterone (male sex hormones) is synthesized from cholesterol in the testes.
• These hormones are also synthesized in little amounts in extra glandular sites, particularly in adipose tissues.
. Cholesterol
Pregnenolone
17-Hydroxypregnenolone Progesterone Dehydroepiendrosterone
Androstenedione
Estrone Testosterone
Estradiol
Role of Gonadal hormones
• The Gonadal hormones play important roles in
reproduction, in the menstrual cycle, and in giving women and men their characteristic physical differences.
• The estrogen and its derivatives have the estrogenic activity in maintaining homeostasis, cell division and protein expression.
• The synthetic or semisynthetic progesterone derivatives are commonly called progestins.
• The major functions of progesterone is preparation of the uterus for pregnancy, maintenance of pregnancy and in maintenance of the female reproductive organs.
• The estrogens and progestins are most extensively used as chemical contraceptive agents for women and in hormone replacement therapy (HRT).
Role of Gonadal hormones
• Testosterone has androgenic (promoting male physical characteristics) and anabolic (muscle building) activities.
• Many synthetic androgenic and anabolic steroids have been prepared and are used to recover from debilitating illness.
• All anabolic steroids have androgenic effects.
Role of Gonadal hormones
• Estrogen products: Estradiol, Estrone, Estriol, Ethinylestradiol.
• Progestins: Progesterone, Hydroxyprogesterone, Medroxyprogesterone, Megestrol, Nomegestrol, Norethindrone, Norgestrel etc.
• The female sex hormones are widely used for the treatment of various gynecological diseases such as primary or secondary amenorrhea, dysmenorrhea and endometriosis.
• The estrogen and progestins are used as Oral Contraceptives.
Role of Gonadal hormones
• The anabolic steroids enhance Skeletal mineralization and bone maturation. They have marked nitrogen retention activity.
• The anabolic agents decrease calcium excretion by the kidney and result in increased deposition of both calcium and phosphorous in bone.
• They also increase red blood cell formation.
The adrenocortical hormones
• The glucocorticoids and mineralocorticoids are secreted by the adrenal gland under the influence of peptide hormones secreted by the hypothalamus and anterior pituitary lobe (adenohypophysis).
• The anterior pituitary hormone that influences glucocorticoids synthesis is adrenocorticotropic hormone (ACTH; corticotrophin).
• The corticotrophin-releasing factor (CRF) is released by the hypothalamus that stimulate the anterior pituitary to release of ACTH into the bloodstream.
The adrenocortical hormones
• ACTH stimulates the synthesis and secretion of the glucocorticoids.
• The synthesis and secretion of glucocorticoids is regulated in a negative feedback mechanism by adrenal-anterior pituitary-hypothalamus axis.
• Aldosterone secretion rates are influenced to a greater extent by the octapeptide angiotensin-II.
. Cholesterol
Progesterone 17-Hydroxyprogesterone
Desoxycorticosterone 11-Desoxycortisol
Corticosterone Cortisol
Aldosterone
Glucocorticoids
• Glucocorticoids are used as powerful anti-inflammatory and antiallergic agents.
• The Mineralocorticoids (MC) are used for the treatment of Addison disease.
• Addison disease is caused by chronic adrenocortical insufficiency, which may be due to either adrenal or anterior pituitary failure.
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