Flashcards in Repro - control of reproductive processes Deck (67)
What hormones involved in reproduction are produced by the hypothalamus?
GnRH, PRH (prolactin releasing hormone) and PIH (prolactin inhibiting hormone).
What hormones involved in reproduction are produced by the posterior pituitary?
What hormones involved in reproduction are produced by the anterior pituitary?
FSH, LH and prolactin
What hormones involved in reproduction are produced by the testis?
Testosterone, Mullerian inhibiting hormone (MIH) and inhibin.
What hormones involved in reproduction are produced by the ovaries?
Oestrogen, progesterone and inhibin.
What hormones involved in reproduction are produced by the placenta?
Human chorionic gonadotrophin (hCG)
Human placental lactogen (hPL)
Which hormones produced by the anterior pituitary are glycoproteins?
Think: BLT (but using fish not bacon):
FSH, LH and TSH
Which hormones produced by the anterior pituitary are polypeptides?
MSH (melanocyte stimulating hormone)
What type of cell in the anterior pituitary produces FSH and LH?
What type of cell in the anterior pituitary produces ACTH and MSH?
What type of cell in the anterior pituitary produces prolactin?
What is the principle action of FSH?
Growth of the reproductive system
What is the priniciple action of LH?
Sex hormone production
What are the principle actions of ACTH?
Secretion of glucocorticods, mineralocorticoids (though the main regulator of secretion is by angiotensin) and androgens.
What are the main target tissues of growth hormone?
Liver and adipose tissue
What are the principle action of growth hormone?
Promotes growth, lipid and carbohydrate metabolism.
What are the main target tissues of prolactin?
Ovaries and mammary glands.
What are the principle action of prolactin?
Secretions of oestrogen, progesterone and milk production.
What is the effect of testosterone on GnRH secretion?
Reduced GnRH secretion
What secretes GnRH?
Several groups of hypothalamic neurones secrete it in a pulsatile fasion (about one pulse an hour)
What is the effect of intermediate concentration of oestrogen on GnRH secretion?
Reduces secretion - lowers amount secreted per pulse
What is the effect of progesterone on GnRH secretion?
Increases the inhibitory effect of oestrogen - lowers the FREQUENCY of the pulses
What is the effect of oestrogen alone (no progesterone) at high concentrations?
Promotes the release of GnRH producing a surge. Progesterone prevents this.
What secretes inhibin?
1. Developing follicles (granulosa cells) in the ovary
2. Seminiferous tubules (sertoli cells) in the testis
What is the effect of inhibin on the HPG axis?
Inhibin reduces the amount of FSH secreted by the anterior pituitary in response to GnRH.
What is the effect of LH on:
1. The testis
2. The ovaries
1. Binds to Leydig cells to promote the secretion of testosterone
2. Binds to theca interna cells, promoting the release of androgens (mainly androstenedione)
What is the effect of secretion of testosterone from Leydig cells on the testis and body in general?
Testosterone act on sertoli cells promoting spermatogenesis. It also acts elsewhere in the body maintaining the male reproductive system (maintains internal genitalia, metabolic and behavioural effects).
What are the effect of prolactin and inhibin on Leydig cells?
prolactin and inhibin enhance the effects of LH and therefore secretion of testosterone from Leydig cells.
What are the effects of FSH on the testis?
FSH maintain sertoli cells, making them responsive to testosterone.