Week 6 Flashcards
Hypogonadism meaning + origins
The term “Hypogonadism” designates a deficiency in
ovary or testicular function.
There are several possible origins, including, the
absence of sexual development in an individual, or,
feminine or masculine sterility.
This disorder can result from a congenital anomaly
(Turner Syndrome) or from consuming vegetables that
were grown in soil that is rich in cadmium.
Clinical Syndromes of hypogonadism
In men, hypogonadism is presented by a deficiency in
testicular function.
This concerns sperm production and the testosterone
secretion.
This pathology is evoked in pubescent males around the age of 14 years.
In women, hypogonadism manifests in three forms:
Primary hypogonadism
Secondary hypogonadism
Menopause
Reproductive Hormones- Regulation
In both sexes, the hypothalamus monitors and causes the release of hormones from the pituitary gland. When the reproductive hormone is required, the hypothalamus sends a gonadotropin-releasing hormone (GnRH) to the anterior pituitary.
This causes the release of follicle stimulating hormone (FSH) and luteinizing hormone (LH) from the anterior pituitary into the blood.
Note that the body must reach puberty in order for the adrenals to release the hormones that must be present for GnRH to be produced
Carrier proteins for Sex Hormones
Sex hormone binding globulin (SHBG) is a
protein that affects the function of some sex
hormones,including testosterone and estrogen
It is primarily made in the liver .
In short, SHBG binds to specific sex
hormones, removing them from direct
circulation in the body.
It binds tightly to testosterone,
dihydrotestosterone (DHT), and estradiol (an
estrogen) and transports them in the blood in
an inactive form.
Reproductive Hormones (male)
At the onset of puberty, the hypothalamus causes the release of FSH and LH into the male system for the first time.
FSH enters the testes and stimulates the Sertoli cells to begin facilitating spermatogenesis using negative feedback.
LH also enters the testes and stimulates the interstitial cells of Leydig to make and release testosterone into the testes and the blood.
Testosterone, the hormone responsible for the secondary sexual characteristics that develop in the male during adolescence, stimulates spermatogenesis.
These secondary sex characteristics include a deepening of the voice, the growth of facial, axillary, and pubic hair, and the beginnings of the sex drive.
Reproductive Hormones (female)
As with the male, the anterior pituitary hormones cause the release of the hormones FSH and LH.
In addition, estrogens and progesterone are released from the developing follicles.
Estrogen is the reproductive hormone in females that assists in endometrial regrowth, ovulation, and
calcium absorption; it is also responsible for the secondary sexual characteristics of females.
These include breast development, flaring of the hips, and a shorter period necessary for bone
maturation.
Progesterone assists in endometrial re-growth and inhibition of FSH and LH release.
In females, FSH stimulates development of egg cells, called ova, which develop in structures called follicles.
Follicle cells produce the hormone inhibin, which inhibits FSH production.
LH also plays a role in the development of ova, induction of ovulation, and stimulation of estradiol and
progesterone production by the ovaries.
Estradiol and progesterone are steroid hormones that prepare the body for pregnancy.
Estradiol produces secondary sex characteristics in females, while both estradiol and progesterone
regulate the menstrual cycle.
Male hypogonadism
A decrease in either of the two major
functions of the testes:
sperm production
testosterone production
Primary hypogonadism
Testes
Serum Testosterone↓, FSH & LH ↑
Secondary hypogonadism
Pituitary gland or Hypothalamus
Serum Testosterone↓, FSH & LH
↔ , ↓
Testosterone function
Male sexual differentiation Secondary sex characteristic in puberty and adult Spermatogenesis Muscle strength, Muscle volume Bone density Erythropoeisis
Androgen Deficiency Symptoms
Musculoskeletal
• Decreased vigour and physical energy
• Diminished muscle strength
Sexuality • Decreased interest in sex • Reduction in frequency of sexual activity • Poor erectile function/arousal • Loss of nocturnal erections • Reduced quality of orgasm • Reduced volume of ejaculate
Male hypogonadism: Onset
Postpubertal onset
Loss of libido
Impotence
Infertility
Primary hypogonadism (male): Cause
Postpubertal onset Infections — Mumps orchitis Radiation Drugs Trauma Bilateral orchiectomy Autoimmune damage Chronic systemic diseases (Cirrhosis, Chronic renal failure, HIV)
Secondary hypogonadism (male): Cause
Prepubertal onset Isolated idiopathic hypogonadotropic hypogonadism Kallmann's syndrome Idiopathic hypogonadotropic hypogonadism associated with mental retardation Abnormal ß-subunit of LH Abnormal ß-subunit of FSH Idiopathic hypogonadotropic hypogonadism associated with other hypothalamic pituitary hormonal deficits
Postpubertal onset Sella or suprasellar tumor Infiltrative disease > Sarcoidosis, eosinophilic granuloma → hypothalamic hypogonad > Hemochromatosis → pituitary hypogonad Infection: meningitis Trauma Critical illness: surgery, MI, head trauma Chronic systemic illness : cirrhosis, CKD, HIV Drugs
Investigation for hypogonadism
Serum Testosterone, FSH,LH
Semen analysis
Others Peripheral leukocyte karyotype Other pituitary hormones Serum prolactin Iron saturation MRI brain
Testosterone replacement
Intramuscular preparations Transdermal patch Transdermal gel Oral agent Testosterone pellet Buccal testosterone tablets
Female hypogonadism
Describes the inadequate function of the ovaries, with impaired production of germ cells (eggs) and sex hormones (oestrogen and progesterone).
Primary hypogonadism refers to a condition of the ovaries (primary ovarian insufficiency/hypergonadotropic hypogonadism).
Secondary hypogonadism refers to the failure of the hypothalamus or pituitary gland (hypogonadotropic hypogonadism).
