FEMALE SEX HORMONES PHG 224 BY DR AGBARAOLORUNPO

OBJECTIVES LIST OF FEMALE SEX HORMONES LIST THE SITES OF PRODUCTION OF THE HORMONES DESCRIBE THE SYNTHESIS OF FEMALE SEX HORMONES DISCUSS THE FUNCTIONS OF FEMALE SEX HORMONES DESCRIBE THE REGULATION OF FEMALE SEX HORMONE DESCRIBE THE MECHANISMS OF ACTION OF FEMALE REPRODUCTIVE HORMONE

FEMALE SEX HORMONES ESTROGENS PROGESTERONES RELAXIN

1. 17β-estradiol (most potent) 3 types of estrogens 1. 17β-estradiol (most potent) 2. Estrone 3. Estriol (least potent) They are C18 steroids

Synthesis of estrogens Secreted by theca interna and granulosa cells of ovarian follicles, the corpus luteum and placenta Formed from androgens and aromatization of androstenedione(catalyzed by aromatase) Only two percent of estradiol is free and active the rest is bound to and transported by plasma protein(albumin-60% and steroid binding testosterone-38%) Pathway for the synthesis of estrogen Acetate→cholesterol →pregnenolone→ progesterone→ Testosterone(androgen)→Estrogen About 1/15th of testosterone is secreted by the ovaries into the plasma Or cholesterol→androstenedione→estradiol

Ovarian follicle Uterus Fallopian tube Vagina Breast Bones Metabolism FUNCTIONS OF ESTROGEN Ovarian follicle Uterus Fallopian tube Vagina Breast Bones Metabolism

Conditions affected by estrogens Puberty Pregnancy Lactation Menstrual cycle Malignancy Menopausal syndrome

Development of secondary sex characteristics at puberty: Enlargement of breast, uterus and vagina. Body configuration: figure eight shape :narrow shoulder, broad hips, thigh that converges and diverging arms, distribution of fat in the breasts and buttocks, less body hair, more scalp hair, pubic hair and axillary hairs Pelvis-broaden High pitch voice Other functions of estrogens Salt and water retention-weight gain just before menstruation

BREAST DEVELOPMENT development of stroma tissues and duct of breast during puberty and pregnancy Deposition of fat in the ductile system of breast Breast enlargement Pigmentation of areolar Lactation-preparation of breast ductile system for lactation Topical estrogen cream-for breast enlargement

Ovarian follicle development during menstrual cycles. Cyclic change(enlargement) in endometrium, cervix and vagina

EFFECT ON UTERUS Enlargement –proliferation of endometrial cells Increase blood supply to endometrium+ blood vessel supply Deposition of fat and glycogen Increase in spontaneous activity and contractility of uterine muscle Increase sensitivity to oxytocin FALLOPIAN TUBES Increase the growth and activity of ciliated epithelium to aid movement of ovum VAGINA Proliferation of vaginal epithelium[cuboidal→stratified epithelium] ↓es PH of vagina[acidic vagina To prevent some vagina infection Estogeng therapy-for curing such infection

Effect on bones Osteoblastic activity-increases bone growth at puberty Causes early fusion of epiphysis with the shaft [this effect is stronger than similar effect of testosterone in male and hence growth of females usually ceases earlier than in males] Postmenopause: estrogens ↓es→osteoporosis→fragile bone→high risk of bone fractures Effect on electrolytes and water balance Sodium and water retention by kidneys Less significant prior to pregnancy More significant during pregnancy Effect on Metabolism Protein-anabolism=↑total body protein Fat-deposition of fat in the subcutaneous,tissues,breasts,buttocks and thighs

Regulation of estrogen secretion Estrogen secretion is regulated by FSH [from anterior pituitary gland] FSH release is stimulated by gonadotropin-releasing hormone[GnRH] from hypothalamus FSH acts on its receptors in theca cells and granulosa cells via cAMP→estrogens secretion Estrogen inhibits secretion of FSH and GnRH by negative feedback Inhibin secreted by granulosa cell s also decreases estrogen secretion by inhibiting FSH and GnRH

progesterone C21 Steroid Synthesized from acetate and cholesterol Synthesized in ovaries, corpus luteum, placenta and adrenal cortex[very small amount]

FUNCTIONS OF PROGESTERONE Fallopian tube Increases the secretory activity of FT This is Necessary for nutrition of fetus before implantation Cervix Increases the thickness of cervical mucosa. This prevent sperm transportation to uterus Utilized in contraceptives Breast development Development of lobules and alveoli of breast Increases the secretory activity of the breast Thermogenic effect Increase body temperature after ovulation by acting on hypothalamus Respiration Increases ventilation during pregnancy and luteal phase of respiration

Uterus Promotes the secretory activity of uterine endometrium in preparation for implantation Increases the deposition of lipid and glycogen in endometrium Blood supply+gland growth in the uterus Decreases the sensitivity of uterus to oxytocin during pregnancy Electrolytes and water balance Sodium and water retention Hypothalamus Progesterone Inhibits LH secretion from anterior pituitary gland through negative feedback inhibition.

Regulation of progesterone secretion LH stimulates corpus luteum to secreye progesterone Secretion of LH is influenced by gonadotropin-releasing hormone[]GnRH from hypothalamus Progestrone the inhibits LH releas from anterior pituitary by negative feedback inhibition

RELAXIN Polypeptides hormones Produced in corpus luteum,uterus,placenta and mammary glands in women and prostate gland in men Relaxes pubic symphysis,pelvic joints and softens and dilates uterine cervix during pregnancy In non-pregnant women-functions unknowns Increase sperm motility in men