This document discusses the female sex hormone oestrogen. It notes that oestrogen, along with androgens and progestins, are the three main sex hormones produced in the gonads. Oestrogen is produced primarily in the ovaries and its secretion is controlled by FSH. The key functions of oestrogen include regulating ovulation and menstruation, developing secondary sex characteristics, and preparing the reproductive tract for pregnancy. Oestrogen acts by binding to estrogen receptors in target tissues. The document outlines the different types of estrogens and their biosynthesis and physiological effects. It also discusses structure-activity relationships and clinical uses and side effects of estrogens.

1. Female Sex Hormone
Oestrogen
Dr. Jasmine Chaudhary
Associate Prof., MMCP
MM(DU), Mullana

2. Introduction
 Hormones secreted by ductless/ endocrine glands in minute
amounts and exert important functions on other tissues.
 3 main sex hormones are
 Androgens (Male sex hormone)
 Oestrogens (Female sex hormone)
 Progestins/ Progesterone (Corpus Luteum hormone)
 These hormones are produced in gonads i.e. mainly testis in male
and ovary in females and their secretion is under the control of 3
hormones:
a) FSH b) LH/ICSH c) Prolactin/Leutropin
Lecture by Dr. Jasmine Chaudhary

3. Functions
 Regulation of ovulation in women and spermatogenesis in
male.
 Development of secondary sex characters in both.
 Stimulation and growth of mammary gland.
 Maintainence of endometrium to prepare reproductive tract for
fertilization and implanatation.
 Growth and development of bones in both.
Lecture by Dr. Jasmine Chaudhary

4. Estrogens
 Female sex hormone which are produced mainly in the
follicles present in ovary and their secretion is controlled by
FSH released from anterior pituatory.
 Also secreted in placenta, testis, liver, skeletal muscles and
hair follicles.
 Main precursor is cholesterol which get converted to
androstenedione which then form estradiol or estrone by the
action of enzyme aromatase
 These are derivatives of esrtrane having C-18 skeleton.
Lecture by Dr. Jasmine Chaudhary

5. Physiological Functions
• Development of female reproductive tract and stimulate
ovulation.
• Development of female secondary sex characters i.e.
distribution of body fat to produce female body contour,
growth of axillary and pubic hair, feminine voice.
• Stimulation of proliferative phase of endometrium (Initial
growth of endometrium during menstrual cycle)
• Vasodilation and Cardioprotection
• Maintain integrity of skeleton in reproductive age (Growth of
uterus during puberty)
Lecture by Dr. Jasmine Chaudhary

6. Mode of Action
Bind to estrogen receptor in target organ
Oesrogen receptor complex
Enters nucleus
mRNA synthesis
Protein synthesis
Lecture by Dr. Jasmine Chaudhary

7. Classification
 Natural estrogens/ Human estrogens: Estrone, Estradiol,
Estriol
 Semi-synthetic estrogens: Mestranol, Ethinyl estradiol
 Synthetic estrogens: Diethyl stilbestrol, Benzesterol,
Dienestrol
Lecture by Dr. Jasmine Chaudhary

8. Natural estrogens
 Secreted by the ovary.
 Synthesized in the graafian follicle, corpus luteum and placenta
from cholesterol.
Estradiol Estrone Estriol
Drawbacks
Inactive orally
Rapid metabolism in liver
Have short duration of action
Lecture by Dr. Jasmine Chaudhary

9. SAR
 17β-estradiol is most potent but oxidise to estone in liver thus
addition of 17α-alkyl group like in ethinyl estradiol block
oxidation in liver and compound will become effective orally.
 Aromatic ring with C-3-OH is essential for activity. Its’s
removal will decrease activity.
 Steroidal structures is not essential for activity.
 Epimerization of 17β-OH decrease the activity.
 Alkylation of the aromatic ring decrease the activity.
Lecture by Dr. Jasmine Chaudhary

10.  The group between the two hydroxyl must be hydrophobic.
 Unsaturation of ring B decreases the activity.
 17a- and 16 position when modified enhance the activity.
 Phenolic ring A is principle structural feature responsible for
binding to receptor.
 The 17 beta-hydroxyl with constant distance from 3-OH is
essential for activity.
Lecture by Dr. Jasmine Chaudhary

11. Biosynthesis of Estrogens
Lecture by Dr. Jasmine Chaudhary

12. Uses
 In menstrual disorders like amenorrhea, dysmennorrhea
 In infertility (Anovulation)
 Replacement therapy in estrogen deficient patients.
 In abnormal uterine bleeding.
 Dermatological disorders (Acne vulgare)
 In contraception (along with progestogen)
 In treatment of breast cancer and various genital problems.
Lecture by Dr. Jasmine Chaudhary

13. Side effects
 Nausea and vomiting
 Headache
 Weight gain
 Salt and water retention so increased BP.
 Anorexia
 Migraine and hypertension.
Lecture by Dr. Jasmine Chaudhary

14. Diethyl stibesterol (DES)
•Also known as stilbestrol
•Synthetic and nonsteroidal estrogen which differs from
natural estrogen estradiol in various ways.
• Compared to estradiol, DES has
improved bioavailability when taken by mouth,
More resistant to metabolism,
Shows relatively increased effects in certain parts of the body
like the liver and uterus.
These differences result in DES having an increased risk
of blood clots, cardiovascular issues, and certain other adverse
effects.
Lecture by Dr. Jasmine Chaudhary

15. Lecture by Dr. Jasmine Chaudhary