Ovarian hormones-Estrogen & Progesterone

Focused on livestock.

1. WELCOME

2. OVARIAN HORMONE- ESTROGEN & PROGESTERONE Surya Adhikari B V SC & AH, NEPAL [email protected]

3. INTRODUCTION Ovary is the primary female sex organ that produces two main steroid hormones. Estradiol - Steroid Progesterone- Steroid Androgen-Steroid Relaxin - Protein These hormones exert their action on the female genital tract and mammary gland . Note- Progesterone & Relaxin is only found in female.

4. ESTROGEN

5. The estrogens are steroidal hormones synthesized from cholesterol and produced primarily by the ovaries, placenta and corpus luteum. A significant source of estrogens is the testes of stallions and boars, while a minor source is the adrenal gland. The estrogens are metabolized by the liver and excreted in the bile, feces, and the urine (horses and ruminants). Progesterone decreases the effects of the estrogen and FSH and LH may be involved in estrogen secretion.

6. SOURCES OF ESTROGEN Granulosa cells of ovarian follicle, placenta, and corpus luteum. Adrenal cortex also produces estrogen. Estradiol – predominates in non-pregnant animals Estrone – predominates in pregnant animals Estriol – predominates in pregnant primates Plant estrogen is also found in legumes – Clover and Alfa Alfa which cause infertility in animals. Binding proteins in the circulation carry estrogen.

7. FUNCTIONS OF ESTROGEN Maturation growth and development of the reproductive organs. Stimulation of normal physiological processes of the tubular reproductive tract. growth of the uterine muscle development of the endometrial lining of the uterus increase the vascularity of the uterus Induction of behavioral estrus Dilation of the cervix, liquefaction of mucous plug. Under the influence of the estrogens the uterus is less susceptible to infection.

8. It aids in sperm transport by increasing the Myometrial contractions. The estrogens inhibit the secretion of FSH and LH via a negative feedback mechanism The estrogens are involved in the regression of the corpus luteum. Estrogen priming promotes the growth of the endometrial glands. Necessary for maintenance of zygote and helps implantation of zygote.

9. At the time of parturition, it sensitizes the pregnant uterus to oxytocin, thus aid the uterine contraction along with oxytocin and PGF 2 α. for the expulsion of fetus. Estrogen increase the rate of migration of leukocytes into the uterine lumen, and thus increases the bactericidal activity of the uterus during estrum. Estrogen priming promotes the growth of the endometrial glands. Necessary for maintenance of zygote and helps implantation of zygote. Regulates the release of FSH and LH from the anterior pituitary by its feedback mechanism.

10. Secondary sexual characters Estradiol is responsible for the secondary sex characteristic of the female It causes the growth of the duct system of the mammary gland It stops growth of long bones by initiating the closure of epiphyseal growth plate It causes disposition and distribution of body fat. They are required for the development of the secondary sex characteristics of the female including hair growth, deposition of body fat, mammary gland development, plumage, etc. Protein anabolism in ruminants They play a role in the normal health and function of the skin

11. SUMMARY- EFFECTS OF ESTROGEN ON REPRODUCTIVE TRACTS VAGINA - slight mucous secretion, hyperemia, oedema CERVIX – Relaxation, Liquefaction of mucous plug UTERUS- Stimulates uterine gland development, sensitization of the endometrium to oxytocin, immune activation (local), leucocyte infiltration, secretion of the PGF 2 alpha and PGE 2 FALLOPIAN TUBE -Increased motility & cilia activity MAMMARY GLAND- Stimulates mammary duct development CORPUS LUTEUM - Leutolytic (bovine & ovine) but leucotrophic (equine and porcine)

12. SIDE EFFECTS Prolonged use or large doses can produce cystic ovaries or ovarian atrophy Because of its effect on the ligaments, the estrogens predispose to prolapse of the vagina and rectum and dislocations and fractures of the pelvic bones. In the dog excessive amounts or prolonged administration of estrogens can produce a fatal anemia - leukopenia and thrombocytopenia. In some species the estrogens in combination with progesterone may increase the incidence of cystic endometrial hyperplasia - pyometra complex. 

13. ESTROGEN - COMMERCIAL USE In ruminants, estrogen also have a protein anabolic effect to increase body weight gain and growth. The possible mechanism for increased growth may be due to the ability of estrogens to stimulate the pituitary to release more growth hormone. Diethyl stilbesterol – a synthetic nonsteroidal estrogen was formerly used for growth promotion. Estrogen have been used to abort cows and sheep because of their luteolytic property. Regression of CL Treatment Post partum metritis Retained placenta Mummified fetus Pyometra It is epitheliotropic and causes growth of soft skin. So used in ointments in skin ailments, produce cornification of vaginal epithelial in certain type of vaginitis.

14. INDICCATIONS They are used to evacuate the uterus in cases of fetal mummification, fetal maceration and Pyometra. They are used to induce abortion in all species They can be used in the treatment of postpartum metritis and retained fetal membranes Used in the management of misalliance in dogs To produce signs of estrus in anestrual animals Treating cases of estrogen responsive urinary incontinence

15. In virgin heifers and dry cows estrogen can be used to stimulate mammary development and lactation Large doses of estrogen after parturition can be used to inhibit lactation and relieve congestion of the mammary glands. Used as growth promotants in beef cattle Used in the management of skin condition in spayed bitches In treating male dogs with prostatic hyperplasia Can be used to decrease libido in males

16. PROGESTERONE These include the naturally occurring steroid progesterone which is synthesized from cholesterol and produced by the corpus luteum (main source), placenta (especially of the ewe and mare after the first 1/3 and 1/2 of gestation respectively), the adrenal gland and the testes, as well as a number of synthetic progesterone which are much more potent and have a longer half-life than progesterone.

17. SOURCES Luteal cells of corpus luteum Also produced from adrenal cortex and placenta.

18. FUNCTIONS Progesterone causes growth of the glandular system of the endometrium of the uterus, and the secretions from the endometrial glands (uterine milk) for the nutrition of the ovum and the attachment of the embryo. Progesterone plays a role in the maintenance of pregnancy (and pseudopregnancy ) by providing a favorable environment for survival of the embryo. Progesterone causes growth of the alveolar system of the mammary gland. Progesterone inhibits the smooth muscle activity of the uterus - renders it less sensitive to oxytocin.

19. Target tissues are relatively insensitive to progesterone unless primed by estrogen - At low levels progesterone acts with estrogen to stimulate ovulation by promoting LH release. At high levels progesterone inhibits the secretion of FSH and LH via a negative feedback and thus also prevents the ovulation of follicles during the luteal phase and during pregnancy. Progesterone increases the efficiency of nutrient utilization.  

20. EFFECTS ON PEPRODUCTIVE ORGANS Vagina- slight mucous secretion, paleness, exfoliation Cervix- Closure, formation of mucous plug Uterus- stimulates uterine gland secretions, sensitization of endometrium to oxytocin, decreases uterine motility, inhibition of PGF2 alpha & PGE2. Fallopian tube- increased secretion , decreased motility Mammary gland – Stimulates lobulo -alveolar development

21. APPLICATIONS Prevent or control habitual abortion due to an actual or possible progesterone deficiency. Estrum deferment or suppression in the ewe, cow, sow, mare and bitch. Synchronization of estrus in the mare, ewe, cow and sow. In heifers the progestins are used to promote growth - suppresses heat

22. To treat post-partum hemorrhage in the bitch. In cats progesterone has been used to treat miliary eczema and eosinophilic granulomas. Progesterone has a calming as well as androgenic effect and has been used to manage antisocial or aggressive behavior in mares, stallions, dogs and cats.

23. THANKS