Male and female reproductive endocrinology Flashcards
What is the purpose of GnRH?
released from hypothalamus to act on anterior pituitary to release LH and FSH. these gonadotrophic hormones control sexual maturation and gametogenesis.
What is the purpose of gonadorelin 2 and its analogues?
mainly treats infertility and some hormone dependent tumours
What is the function of kisspeptin?
initiates secretion of GnRH at puberty. linked with sexual bonding.
What is the function of neurokinin B?
controls secretion of GnRH. possible roles in pregnancy, sexual maturation and menopause. implicated in menopausal flushing. NK3 receptor block reduces flushing.
Where can neurokinin B be found?
arcuate nucleus of hypothalamus (with kisspeptin and dynorphin), where these mediators are implicated in generating pulsatile release of GnRH
Outline hormonal control of the female reproductive system
GnRH is secreted frompeptidergicneurons in hypothalamus in apulsatile fashion.
GnRH stimulates anterior pituitary to release FSH and LH whichact on ovaries to promote development of small groups offollicles, each containing anovum.
One follicle develops fastest and forms theGraafian follicle (GF), whichsecretes oestrogens.
Which phase of the menstrual cycle is oestrogen responsible for?
proliferative phase of endometrial regeneration, which occurs from day 5 or 6 until mid-cycle.
during this phase, the endometrium increases in thickness and vascularity. at the peak of oestrogen secretion, there is a prolific cervical secretion of mucus, facilitating the entry of spermatozoa.
What happens at the beginning of the menstrual cycle?
begins with mensuration, lasting between 3-6 days, in which the superficial layer of endometrium is shed. the endometrium regenerates during the follicular phase of the cycle after menstrual flow has stopped.
What is the function of inhibins and where are they produced?
mainly produced in gonads.
provide negative regulation of FSH secretion, but also have paracrine/autocrine actions in gonads and adrenal gland.associated with antagonism of activinsignalling.
What is measuring inhibins in circulation a reliable marker for?
some types of ovarian cancer, and also a predictor for the conditions of spermatogenesis
What is day 3 serum inhibin-B predictive of?
women with low day 3 serum inhibin-B concentrations demonstrate a poorer response to ovulation induction and are less likely to conceive a clinical pregnancy through ART (assisted reproductive technology), relative to women with high day 3 inhibin-B.
What are the effects of testosterone
Increased aggression and libido* Enlargement of larynx Male pattern pubic hair Maturation of genitalia Muscle development Sperm production Bone growth* Acne * requires conversion to oestradiol by aromatase.
