Estrogen Seminar created by : kumar samudra gupta kaushik Roll no.- 20
Physiological functions Developemnt of female reproductive tract Developemnt of female secondary sex characters Stimulation of proliferative phase of endometrium Vasodilation Cardioprotection Maintain integrity of skeleton in reproductive age
Natural estrogens: secreted by the ovary. synthesized in the graafian follicle, corpus luteum and placenta from cholesterol.
Synthetic estrogen: long duration of action slow metabolic rate.
Structure Activity Relation Ships: Aromatic ring with C-3-OH is essential for activity. Steroidal structures is not essential for activity. Alkylation of the aromatic ring decrease the activity. The 17 b -hydroxyl with constant distance from 3-OH is essential for activity. The group between the two hydroxyl must be hydrophobic. Unsaturation of ring B decreases the activity. 17 a - and 16 position when modified enhance the activity.
NATURAL ESTROGENS Estradiol – known also as 17 β – estradiol Principle estrogen in premenopausal women Estrone – 1/3 the estrogenic potency of Estradiol Primary circulating estrogen after menopause Estriol – significantly less potent than estradiol Present in significant amounts during pregnancy, because its principal estrogen produced by placenta.
Estradiol Estriol Estrone Testosterone Androstenedione Aromatase Aromatase Synthesis of Estrogen
Estrogen receptors The steroid receptor complex undergoes changes and binds with estrogen responsive element located on target gene where it brings about changes in transcription. . 2 estrogen – receptor subtypes mediate the effects of the hormone α receptor – the classic Estrogen Receptor. Found in breasts,hypothalamus,endothelial cells and vascular smooth muscle. β receptor – highly homologous to the α receptor.found in bone, brain, ovaries α receptor N - terminal portion of receptor contains a region that Promotes transcription activation. β receptor contains a Repressor Domain
ACTIONS ON SEX ORGANS: Estrogens bring about pubertal changes in the female including growth of uterus, fallopian tubes and vagina. It suppress the activity of FSH, and stimulate the secretion of LH by direct action on pituitary as well as through hypothalamus. It enhances the rhythmic contraction of the fallopian tubes and uterus and induce a watery alkaline secretion from the cervix.
METABOLIC EFFECTS: Estrogen is important in maintaining bone mass primarialy by retarding bone resorption . Osteoclast pit formation is inhibited bone matrix proteins increase such as osteonectin,osteocalcin,collagen etc. It controls the action of parathormone , hormone which intake calcium ions from bones and teeth, thus maintaing a positive calcium balance. Cause salt and water retention edema Estrogens decrease plasma LDL cholesterol while HDL and triglycerides levels are raised atherosclerosis in premenopausal women. Blood coagulation is increased due to the formation of various clotting factors. It promotes vasodilation by induce secretion of nitric oxide synthase (NO) and PGI2.
Therapeutic uses Contraception HORMONE REPLACEMENT THERAPY: In women after menopause due to the cessation of ovarian function as estrogen- progestin HRT therapy suppression of vasomotor instability Osteoporosis Senile vaginitis : can change vaginal cytology and effective in preventing atrophic vaginitis in elderly women .
Adverse Effects Most common estrogen therapy Nausea Breast tenderness Post menopausal uterine bleeding may occur There is increased risk of : Myocardial infarction Breast cancer Endometrial cancer Other effects Headache Peripheral edema Hypertension
Referance Razdan Balkishen , Medicinal Chemistry,First Edition:2010,CBS publishers & Distributors Pvt. Ltd., Page No.-497-500. Tripathi KD, Essentials of Medical Pharmacology,Seventh Edition:2013, Jaypee Brothers medical Publishers (P) Ltd, Page no-306-311. Pharmacology and pharmacotherapeutics by r.s satoskar,21 st edition,2012,popular prakashan,935-942.