1. E7-1 Hormonal Control of Reproduction femalemale Dendrobates azureus

2. E7-2 Hormonal Control of Reproduction 1. Critical importance to fitness “its ability to perpetuate itself as measured by its reproductive success” (Pianka 2000) Energetically expensive Therefore, must be precisely timed to insure maximal survival of young young born at time most favorable for survival in cyclical environment

3. E7-3 2. Control of Reproduction HYPOTHALAMUS ADENOHYPOPHYSIS GONAD: TESTIS OR OVARY MEDIAN EMINENCE

4. E7-4 DAYLENGTH

5. E7-5 DAYLENGTH TEMPERATURE

6. E7-6 DAYLENGTH TEMPERATURE NUTRITION

7. E7-7 DAYLENGTH TEMPERATURE NUTRITION ENDOGENOUS CLOCK

8. E7-8 Gonadotropin-Releasing Hormone (GnRH) DAYLENGTH TEMPERATURE NUTRITION ENDOGENOUS CLOCK

9. E7-9 GnRH Stimulates Gonadotropins: Luteinizing Hormone (LH) Follicle-Stimulating Hormone (FSH)

10. E7-10 3. Functions of gonadotropins a. Stimulate gametogenesis production (meiosis) and maturation of gametes Male: spermatozoa Female: oocyte

11. E7-11 b. Stimulate steroidogenesis steroid hormone production by gonads Male: androgens (testosterone) Female: estrogens (estradiol) progestins (progesterone) androgens Actions similar in male and female, only timing and targets that differ

12. E7-12 4. Female system Precise, often brief, secretion of gonadotropins in regular cycles Cycles range from multiannual to days

13. E7-13 a. Ovary Structure (1) connective tissue capsule (2) ovarian follicle (1 to millions) oocyte: premeiotic gamete follicle cells: two layers of steroidogenic cells surrounding oocyte inner layer: granulosa outer layer: theca (3) Ducts for oocyte transport and packaging oviduct, uterus

14. E7-14 b. Control of ovarian function LHTheca Cells +

15. E7-15 b. Control of ovarian function LHTheca Cells Androgen +

16. E7-16 b. Control of ovarian function LHTheca Cells Androgen FSH +LH Granulosa Cells + +

17. E7-17 b. Control of ovarian function LHTheca Cells Androgen FSH +LH + + Estrogen Granulosa Cells

18. E7-18 b. Control of ovarian function LHTheca Cells Androgen FSH +LH Granulosa + + Estrogen Blood Granulosa Cells

19. E7-19 b. Control of ovarian function LHTheca Cells Androgen FSH +LH Granulosa + + Estrogen BloodOogenesis Granulosa Cells

20. E7-20 c. Estrogens (1) Local effects (paracrine) Stimulate oocyte and follicle cell growth Oocyte and follicle size increase (2) Distant effects (endocrine) (a) Feedback: slight negative feedback on LH

21. E7-21 (b) Primary Sexual Characteristics Growth of ducts and organs directly responsible for gamete production and transport: ovary, oviduct, uterus (c) Secondary Sexual Characteristics Anatomical structures not directly involved in gamete production, but associated with reproductive activity physical and behavioral: mating receptivity

22. E7-22 (d) Metabolic effects tissue growth follicle, ducts, mammary gland energy storage appetite stimulant fat deposition yolk production vitellogenin : precursor protein of yolk proteins.

23. E7-23 Ovary FSH LH ESTROGEN VITELLOGENESIS LIVER

24. E7-24 Ovary ESTROGEN VITELLOGENIN VITELLOGENESIS (calcium, lipids, carbohydrates, phosphorous) LIVER FSH LH

25. E7-25 Ovary ESTROGEN VITELLOGENIN VITELLOGENESIS (calcium, lipids, carbohydrates, phosphorous) LIVER Follicular growth

26. E7-26 Vitellogenin concentration in blood plasma or serum can be measured by immunoassays known as ELISAs Requires an antibody specific for vitellogenin.

27. E7-27 POST NESTING PRE MATING NESTING

28. E7-28 Female Reproductive Cycles (1) Follicular Phase of the cycle oocyte and follicle growth under influence of estrogen Oocyte can not be fertilized in the follicle

29. E7-29 (2) Ovulation rupture of follicle and release of oocyte stimulated by LH surge Regulation of LH surge: (a) environmental cues e.g., daylength, temperature, substrate, mates, etc. (b) endocrine cues e.g., estrogen positive feedback

30. E7-30 LH surge transforms follicle cells into new endocrine gland: Corpus luteum (CL) External fertilizers: eggs shed, CL very brief cycle ends here Internal fertilizers: eggs retained, CL persists

31. E7-31 (3) Luteal Phase, the CL is steroidogenic Estrogens maintain 1° and 2° sexual characteristics Progestins negative feedback on LH with estrogen prepare female for embryo support stimulate structures essential for embryo survival e.g., uterus, mammary gland, albumin glands All preparation in anticipation of fertilization

32. E7-32 (4) No fertilization CL regresses, negative feedback gone, cycle restarts if CNS permits (5) Fertilization CL persists: progesterone New endocrine gland: placenta Progestins maintained until termination Cycle can be manipulated: GnRH, steroids