Female Reproductive Endocrinology

Post a comment   Post Comment on Twitter


     1  Female Reproductive Endocrinology Pituitary-Hypothalamus Control of Cycle Female Menstrual Cycle Ovarian Granulosa Cells Ovarian Thecal Cells Actions of Estrogens Actions of Progesterone Fetoplacental Hormones LKS
     2  Events Leading to the LH Surge 1. During the Proliferative Phase of the Menstrual Cycle (about day -7) the concentration of E2 rises as the ovary produces and secretes it in response to Ant. Pit. FSH. 2. An increase in estradiol (E2) leads to an inhibition of both the Hypothalamus [GnRH producing cells] and the Anterior Pituitary gonadotropic cells. In the Ant. Pit. this inhibition to GnRH hypersensitizes the gonadotropic cells to GnRH, But they cannot respond because of the presence of E2. 3. Just before the LH surge, the concentration of E2 decreases, releasing the inhibition on the Ant. Pit. To GnRH. 4. GnRH hyperstimulates the hypersensitized Anterior Pituitary and the response is to hypersecrete LH. There is no progesterone to inhibit LH so all is secreted.
     3  Events Leading to LH Surge 2 5. FSH does not surge quite as much due to the fact that there is still E2 present in the plasma and at the Ant. Pit. So the FSH peak is blunted due to negative inhibition on the FSH release. 6. Thus there is the LH surge, which stimulates the formation of the Corpus Luteum and also leads to ovulation.
     4  Pituitary - Hypothalamus Control of Female Reproductive Function GnRH LH FSH Progesterone Estradiol (-) (+) Hypothalamus Pituitary Ovaries LKS Granulosa Cells Thecal Cells
     5  Prog Estradiol LH FSH LH & FSH mIU/ ml 20 40 80 Prog E2 10 5 500 pg / ml ng / ml 1000 0 -7 +7 -14 +14 Follicular Phase - Proliferation Corpus Luteum - Secretory Phase 60 Female Reproduct- ive Cycle Ovulation [Days] LKS
     6  Embryology of Sex Tissues (1)Male Female Stromal Cells become: Leydig Cells Supporting Cells become: Sertoli Cells Stromal Cells become: Thecal Cells Supporting Cells become: Granulosa Cells
     7  Embryology of Sex Tissues (2)Male Female Wolffian Ducts become: epididymus vas deferens seminal vessicles ejaculatory duct Mullerian Ducts (in presence of Mullerian Inhibitory Substance [MIS] Regress) Wolffian Ducts Regress Mullerian Ducts become: fallopian tubes uterus upper 1/3 of vagina
     8  Embryology of Sex Tissues (3)Male Female Genital tubercle,fold, swelling &Urogenital ridge Become: (In the Presence of dihydrotestosterone) Penis Scrotum Prostate gland Genital tubercle,fold, swelling &Urogenital ridge Become: (In the absence of dihydrotestosterone) Labia majora Labia Minora Clitorus Lower 2/3 of vagina
     9  Ovarian Granulosa Cells Responds to FSH Converts Androstenedione to Estradiol Secretes Estradiol Produces Plasminogen Activator Produces Plasmin LKS
     10  Ovarian Thecal Cells Respond to Pituitary LH Convert Cholesterol to Androgens and Estradiol Provide Androstenedione to Granulosa Cells Produce Collagenase Collagenase + Plasmin = Follicular Rupture LKS
     11  Actions of Estrogens 1 Stimulation of Female Sex Organs (Uterus, fallopian tubes, vagina, mammary glands) Stimulate Follicular growth Stimulate Granulosa cell-LH receptor formation Stimulate secretions (Mucous, sebacous glands) LKS
     12  Actions of Estrogens 2 Stimulate Bone Growth, Epiphysial Plate Closure - serum cholesterol, - glucose tolerance +serum HDL, + TBG, + ShBG (=TeBG), +Progesterone receptors in CL LKS
     13  Actions of Progesterone Stimulates Secretory Endometrium Stimulates Mammary growth & development - Uterine motility, - sodium retention +Ventilation, +Body temperature LKS
     14  Fetoplacental Endocrine Unit Placenta Fetal Adrenal Cortex Fetal Liver LKS
     15  Fetoplacental Compounds Produced Alpha Fetoprotein (non-endocrine) Human Chorionic Gonadotrophin stim. steroidogenesis in CL Human Placental Lactogen (human chorionic somatomammotrophin) lipolytic, insulin antagonistic, stim. mammary growth and development Parathyroid hormone related protein-PTHrP LKS