Reproductive endocrinology Flashcards
Reproductive
Endocrinology
Reproductive endocrinology:
The study of hormones involved in reproduction and the development and function of reproductive organs.
Steroidal Hormone
Steroidal hormone:
A hormone derived from cholesterol, including sex hormones such as androgens, oestrogens and progesterone.
Androgens
Androgens:
Male sex hormones that are critical for sexual differentiation and the development of male characteristics.
Dihydrotestosterone (DHT)
Dihydrotestosterone (DHT):
An androgen that is critical for sexual differentiation in embryos and the maintenance of masculine characteristics.
Testosterone
Testosterone:
An androgen that is critical for sperm generation and the development and maintenance of masculine characteristics.
Oestrogens
Oestrogens:
- Secreted from the ovaries
- Stimulate uterine lining thickening
- Stimulate follicular development
- May inhibit or stimulate FSH or LH release depending on the part of the cycle
Female sex hormones that control the development and maintenance of feminine characteristics and stimulate egg follicle growth ,uterine lining thickening.
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Progesterone
Progesterone:
- Female sex hormones that stimulate the growth of the endometrial lining of the uterus for implantation.
- Released from the empty follicle an egg is released from
- Remains high during pregnancy if egg is released
- Maintains the uterine linking for foetal growth and promotes adaptation for pregnancy
- Increases mucus production at cervical to reduce infection risk and prevent sperm entry
- Inhibits, GNRH, FSH and LH release
Hypothalamic – pituitary axis
Hypothalamic – pituitary axis
The regulatory system that controls the synthesis and release of sex hormones, involving the hypothalamus, pituitary gland and gonads.
Gonadotropin-releasing Hormone (GnRH)
Gonadotropin-releasing Hormone (GnRH):
-synthesized and secreted by the hypothalamus
- stimulates the release of FSH (follicle-stimulating hormone) and (LH) luteinizing hormone.
Follicle-Stimulating Hormone (FSH)
Follicle-Stimulating Hormone (FSH)
- synthesized and secreted from the anterior pituitary gland
- acts on the female gonads to promote sex hormone production and gametogenesis,
- initiates follicular growth.
- stimulates oestrogen release
- stimulates egg maturation
Lutenizing Hormone (LH)
Lutenizing Hormone (LH):
• Secreted from the anterior pituitary gland
• Triggers ovulation
• Converts the follicle into the corpus luteum
- stimulates inhibit release from the ovaries
- levels spike mid cycle
- stimulates follicle development
The menstrual cycle
The menstrual cycle
The 28+/- 4 days cycle of oocyte release and the preparation and shedding of the uterine lining.
Follicular phase
Follicular phase
The phase of the menstrual cycle where the follicle grows and develops into a mature follicle
Ovulatory phase
Ovulatory phase
The phase of the menstrual cycle where the oocyte is released from the ovary.
Luteal phase
Luteal phase
The phase of the menstrual cycle where the corpus luteum develops from the follicle.
- Corpus luteum acts as controller of the uterine environment
- Fertilization occurs: maintenance of a suitable environment for pregnancy or implantation
- No fertilization: uterine lining breakdown
Polycystic ovary syndrome (PCOS)
Polycystic ovary syndrome (PCOS)
* Hormonal disorder affecting the ovaries,
* Characterized by excessive testosterone production and high level of insulin.
* PCOS is defined by a combination of signs and symptoms of androgen excess and ovarian dysfunction in the absence of other specific diagnoses.
* Linked to infertility: anovulatory, infrequent periods, oligorrhoea.
* Linked to obesity and family history
* Abdominal fat deposition linked to insulin resistance
* Insulin resistance inhibits synthesis of sex hormone binding globulin in the liver and SHBG deficiency increases androgens
* L-carnitine and co-enzyme Q may help infertility
* Symptoms include irregular periods, difficulty getting pregnant, excessive hair growth, weight gain, and other related complications.
* Weight loss linked to: reduced hirsutism, partial menstrual cycle restoration, reduced insulin concentrations, reduced testosterone concentrations
Symptoms of polycystic ovary syndrome
Symptoms of polycystic ovary syndrome
* irregular periods
* difficulty getting pregnant
* Anovulation (lack or absence of ovulation)
* hirsutism,
* weight gain
* abdominal fat deposition (connected to insulin resistance)
* acne
* fluid filled sacs or cysts
* alopecia