Centre For Reproductive Biology University of Edinburgh Mechanisms of Anovulation Regulation of Ovarian cycle and its disorders David T Baird Emeritus Professor of Reproductive Endocrinology Centre For Reproductive Biology University of Edinburgh Scotland

OVULATION Extrusion of the appropriate number of eggs of good quality at a time when they can be fertilized (developmentally competent )

Regulation of the Ovarian Cycles and its Disorders Folliculogenesis Physiology of Normal Ovarian Cycle Disorders of Ovulation Ovarian Insufficiency(Primary ovarian failure) Secondary ovarian insufficiency

Folliculogenesis inWomen 

Folliculogenesis inWomen InA InB E2 InA InB AMH InB AMH 

Regulation of the Ovarian Cycles and its Disorders Folliculogenesis Physiology of Normal Ovarian Cycle Disorders of Ovulation Ovarian Insufficiency(Primary ovarian failure) Secondary ovarian insufficiency

Endocrine Control of Ovarian Cycles Ovarian cyclicity is dependant on intact Hypothalamic-Pituitary-Ovarian Axis. Maturational change in Hypothalamic Pituitary Unit at puberty manifest by increasing secretion of FSH and LH and ovarian secretion of estradiol Negative feedback inhibits secretion of FSH (and LH) Positive feedback induces LH surge

Hypothalamic-pituitary-ovarian Axis Kisspeptide

Endocrine Control of Ovarian Cycles Ovarian cyclicity is dependant on intact Hypothalamic-Pituitary-Ovarian Axis. Maturational change in Hypothalamic Pituitary Unit at puberty manifest by increasing secretion of FSH and LH and ovarian secretion of estradiol Negative feedback inhibits secretion of FSH (and LH) Positive feedback induces LH surge

Establishment of ovulatory cycles Early in puberty anovulatory cycles relatively common Manifest by irregularity in length of menstrual cycles and duration of bleeding which are often relatively painless Delay in maturation of H-P to generate LH surge Within a few months regular monthly periods (often painful) become established

Schematic Representation of Hormonal Changes in Human Menstrual Cycle Marshall & Eagleson 1997

Final stage of Follicle Development in Women Selection

Final stage of Follicle Development in Women Selection

Final Selection of the Ovulatory follicle Threshold Single Ovulation LH FSH Atresia Baird 1987

How does ovulatory follicle survive in environment when FSH falls below threshold ? Increasingly sensitive to FSH Paracrine factors within follicle Can use LH as partial surrogate (LH receptors on granulosa cells)

Large Follicles are responsive to LH as well as FSH Normal Cycle Ovarian responses in macaques to pulsatile infusion of follicle-stimulating hormone (FSH) and luteinizing hormone: increased sensitivity of the maturing follicle to FSH. Zeleznik AJ Kubic CJ Endocrinology119:2025-32 (1986) FSH and control of follicle growth in women Glasier AF,BairdDT& Hillier SG J Steroid Biochem 32:167-170(1989) Examination of the relative roles of FSH and LH in the mechanism of ovulatory follicle selection in sheep Campbell BK,DobsonH, BairdDT&Scaramuzzi RJ J Reprod Fertil 117:355-367 (1999)

Local Follicular Factors

Regulation of the Ovarian Cycles and its Disorders Physiology of the Ovarian Cycles Disorders of Ovulation Ovarian Insufficiency(Primary ovarian failure) Secondary ovarian insufficiency

Ovary devoid of oocytes cannot function as an endocrine gland Ovarian Insufficiency (failure) Michel De Vas,Paul Devroey & Bart Fauser Lancet 201011:376(9744):911-21 Ovary devoid of oocytes cannot function as an endocrine gland High levels of FSH and LH ,low estradiol and AMH : often amenorrhoea Reduced number of oocytes may be insufficient to maintain repeated ovarian cyclicity(“incipient ovarian failure”) Multiple causes of primary ovarian insufficiency

Primary ovarian Insufficiency (failure) Michel De Vas,Paul Devroey & Bart Fauser Lancet 201011:376(9744):911-21 Accelerated rate of loss of primordial follicles leads to premature ovarian insufficiency Reduced concentration of AntiMullerian Hormone(AMH) and small antral follicle count (AFC) Rarely “resistant ovary” normal number of oocytes but “resistant “ to development eg. due to mutations in FSHR

2 Hypogonadotrophic Hypogonadism(WHO 1) Secondary ovarian failure Insufficient or inappropriate stimulation of ovary 2 Hypogonadotrophic Hypogonadism(WHO 1) Low levels of LH,FSH and estradiol No bleeding in response to gestogen challenge Hypothalamic causes include Kallman,s Syndrome,craniopharyngioma, and hypothalamic suppression in association with weight loss, stress etc Pituitary causes: Tumour (prolactinoma)Infarction(Sheehan’s Syndrome Amenorrhoea or oligomenorrhoea FSH,LH and Estradiol within normal range but subtle disorder of pattern of pulsatile LH Gestogen challenge positive Polycystic or Multicystic Ovaries Some may be due to failure to respond to estrogen with LH surge leading to anovulatory cycles

Regulation of the Ovarian Cycles and its Disorders Disorders of Ovulation Hypergonadotrophic hypogonadism (Primary ovarian failure or insufficiency) Hypogonadotrophic Hypogonadism( WHO1) Hyperprolactinaemia Normogonadotrophic anovulation (WHO2) Baird DT 1997 Lancet 350:9073,275-279

Mechanisms of Anovulation- Normoganadotrophic Inability to generate LH surge in response to estrogen challenge Lack of maturation of HPO axis at puberty Steroids “ectopic” to HPO axis eg adrenal androgens,progestogens (eg CAH) Dysfunction of Follicle maturation Premature acquisition of LH receptors by small antral follicle Relative lack of FSH at critical point when follicle selected for final ovulatory maturation eg PCO

Mechanisms of Anovulation Failure of follicle rupture LUF Inappropriate LH surge (Stouffer 1999) NSAID (Killick & Elstein 1987 Fert Steril 47: 773-7 Clomiphene (Randall & Templeton 1991 Hum Rep 6: 659-64) Progesterone antagonists (PRMS) Dysfunction of Follicle maturation Premature acquisition of LH receptors by small antral follicle Relative lack of FSH at critical point when follicle selected for final ovulatory maturation eg Polycystic Ovary Syndrome

4 Normogonadotrophic anovulation (WHO 11) Secondary ovarian failure Insufficient or inappropriate stimulation of ovary 4 Normogonadotrophic anovulation (WHO 11) Amenorrhoea or oligomenorrhoea FSH,LH and Estradiol within normal range but subtle disorder of pattern of pulsatile LH Gestogen challenge positive Polycystic or Multifollicular Ovaries Some may be due to failure to respond to estrogen with LH surge leading to anovulatory cycles

Recent reviews on Polycystic Ovary Syndrome Human Reproduction Update, pp. 1–12, 2008doi:10.1093/humupd/dmn015Follicle dynamics and anovulation in polycystic ovary syndromeStephen Franks1,3, Jaroslav Stark2 and Kate Hardy1 Clin Endocrinol (Oxf). 2011 Apr;74(4):424-33. doi: 10.1111/j.1365-2265.2010.03956.x.PCOS Forum: research in polycystic ovary syndrome today and tomorrow.Pasquali R, Stener-Victorin E, Yildiz BO, Duleba AJ, Hoeger K, Mason H, Homburg R, Hickey T, Franks S, Tapanainen JS, Balen A, Abbott DH, Diamanti-Kandarakis E, Legro RS.

Polycystic Ovary Syndrome Phenotype and Endocrine response Menstrual irregularity Obesity Anovulation Signs of androgen excess –hirsutism, acne Enlarged polycystic ovaries with presence of > 10 follicles 4- 8mm diameter in each ovary But up to 25 % of ovaries have evidence of ovulation(Stein Leventhal) and 25% cycles ovulatory Women with PCO show intact negative and positive feedback response to estrogen(Baird et al 1977)

Polycystic Ovary Syndrome Phenotype and Endocrine response High basal LH with fast frequency of LH pulses Hyper-responsive to GnRH Relatively low FSH Women with PCO show intact negative and positive feedback response to estrogen(Baird et al 1977)

Women with PCO have normal levels of estrogen Baird et al 1977

PCO have intact positive feedback to Estrogen Baird et al 1977 JCEM

Anovulatory PCO have raised LH and are hyper-responsive to GnRH Baird et al 1977

Negative and positive feedback to estrogen is intact in PCO Baird et al 1977

Animal Models for PCO Whereas androgen excess in non-primates(eg rodents and sheep) primarily disengages the ability of the hypothalamus–pituitary to generate an ovulation-inducing LH surge, this is not the case in primates. In the latter, altered steroid negative feedback regulation of LH and compensatory hyperinsulinaemia from insulin resistance may disrupt ovulatory function, causing anovulation (Abbott et al., 2002).

Recent reviews on Polycystic Ovary Syndrome Human Reproduction Update, pp. 1–12, 2008doi:10.1093/humupd/dmn015Follicle dynamics and anovulation in polycystic ovary syndromeStephen Franks1,3, Jaroslav Stark2 and Kate Hardy1 Clin Endocrinol (Oxf). 2011 Apr;74(4):424-33. doi: 10.1111/j.1365-2265.2010.03956.x.PCOS Forum: research in polycystic ovary syndrome today and tomorrow.Pasquali R, Stener-Victorin E, Yildiz BO, Duleba AJ, Hoeger K, Mason H, Homburg R, Hickey T, Franks S, Tapanainen JS, Balen A, Abbott DH, Diamanti-Kandarakis E, Legro RS.

Polycystic Ovary Syndrome : aetiology of anovulation Endocrine :Abnormal endocrine HPO axis Low FSH, High LH,Androgens, AntiMullerian Hormone (AMH) Intraovarian Hypertrophied theca Multiple small follicle arrested at 10mm Heterogenity in antral fluid content Low estrogen and high androgen But granulosa cells in vitro can produce estrogen

Granulosa cells Theca cell Polycystic Ovary Syndrome What is the cause of arrest of follicle growth? Granulosa cells Premature luteinization: aquisition of LH receptors ?insulin, IGF Androgens AMH causes reduced response to FSH in vitro. AMH production from GC in anovulatory higher than in ovulatory(Pellat et al 2007 JCEM ,92,240) Theca cell Hypertrophied(Franks, Willis) Greater production of androgens and progesterone in vitro