First off the normal range of FSH for an adult male, range from about 4-25 units of FSH in every liter of blood (U/L) or about 5-20 micro-international units in every milliliter. Although some list the upper range normal as 12 micro-international units.
This is some deep stuff, but the bold paragraphs sum it up for you.
In men, FSH stimulates the testes to produce mature sperm and also promotes the production of androgen binding proteins. FSH levels are relatively constant in males after puberty.
In infants and children, FSH levels rise shortly after birth and then fall to very low levels (by 6 months in boys and 1-2 years in girls). At about 6-8 years, levels again rise before the beginning of puberty and the development of secondary sexual characteristics.
In men, high FSH levels are due to primary testicular failure. This can be due to developmental defects in testicular growth or to testicular injury.
Negative-feedback of GnRH release is exerted by testosterone through androgen receptors present in the hypothalamic neurons and in the pituitary. This is easily demonstrated by the rise in serum LH and serum FSH that occurs after orchiectomy. LH and FSH blood levels continue to rise for a long period after castration, reaching maximum levels as late as 25 to 50 days after surgery.
Although it is generally held that testosterone, the major secretory product of the testis, is the primary inhibitor of LH secretion in men, a number of testicular secretory products, including estrogens and other androgens, have the ability to inhibit LH secretion.
Estradiol, a potent estrogen, is produced both from the testis and from peripheral conversion of androgens and androgen precursors and is the predominant regulator of FSH secretion in the male. Although the concentration of estradiol in the blood of men is relatively low compared with testosterone, it is a much more potent inhibitor of LH and FSH secretion (approximately 1000-fold).
Testosterone acts primarily to feedback at the level of the hypothalamus whereas estrogens provide feedback to the pituitary to modulate the gonadotropin secretion response to each GnRH surge.
Production of LH and FSH is inhibited by negative feedback from estrogens and androgens at both the hypothalamus and pituitary levels. Androgen excess may induce a hypogonadal state whether from exogenous sources
Excess androgens feed back to the pituitary, inhibiting the production and secretion of gonadotropins and leading to hypogonadism. Short stature and precocious puberty develop in these patients. As a result of androgen stimulation, premature enlargement of the penis may occur-, however, because of a lack of gonadotropin stimulation, the testes remain underdeveloped. Basal plasma 17-hydroxyprogesterone levels are often elevated 50 to 200 times above normal levels.
In addition, elevated urinary 17-ketosteroid and pregnanetriol levels may occur. Glucocorticoid therapy results in a reduction of ACTH levels, which induces a decrease in peripheral testosterone, thus stimulating endogenous gonadotropin secretion.
Hypogonadotropic hypogonadism has also been identified after the use of anabolic steroids by athletes. This condition is usually reversible after medications are discontinued, but permanent suppression of gonadotropin may occur.
Hormone / antagonist Life stage Value
Progesterone (nanograms per milliliter or nano-moles per liter) Adult < 1.0 ng/ml
(< 3.18 nmol/L)
17-Hydroxyprogesterone (nanograms per deciliter or nano-moles per liter) Prepubertal < 1.1 ng/dl
(< 3.3 nmol/L)
Adult 5 – 250 ng/dl
( 0.15 – 7.5 nmol/L)
Estradiol (picograms per milliliter or pico-moles per liter) Prepubertal < 10 pg/ml
(< 37 pmol/L)
Pubertal < 23 pg/ml
(< 84 pmol/L)
Adult < 60 pg/ml
(< 185 pmol/L)
Estrone (picograms per milliliter or pico-moles per liter) Adult 10 – 50 pg/ml
(37 – 185 pmol/L)
Estriol (nanograms per milliliter or nano-moles per liter) Adult < 2 ng/ml
(< 7 nmol/L)
FSH (units per liter) Adult 1.0 – 12.0 U/L
LH (units per liter)
Adult 2.0 – 14.0 U/L
SHBG (nano-moles per liter) Adult 6 – 50 nmol/L
Dehydroepiandrosterone (DHEA) (nanograms per deciliter or nano-moles per liter) < 6 years 20 – 130 ng/dl
(0.7 – 4.5 nmol/L)
6-8 years 20 – 275 ng/dl
(0.7 – 9.5 nmol/L)
8-10 years 31 – 345 ng/dl
(1.1 – 12 nmol/L)
10-20 years 110 – 900 ng/dl
(3.8 – 31.2 nmol/L)
> 20 years 160 – 800 ng/dl
(5.6 – 27.8 nmol/L)
Dehydroepiandrosterone sulfate (DHEAS) (micrograms per deciliter or micro-moles per liter) 1-8 years 10 – 20 µg/dl
(0.3 – 0.5 µmol/L)
8-10 years 30 – 50 µg/dl
(0.8 – 1.4 µmol/L)
10-12 years 30 – 40 µg/dl
(0.8-1.1 µmol/L)
12-14 years 80 – 140 µg/dl
(2.2 – 3.8 µmol/L)
14-50 years 110 – 690 µg/dl
(3.0 – 18.7 µmol/L)
Androstenedione (nanograms per milliliter or nano-moles per liter) < 6 years 0.1 – 0.2
(0.3 – 0.7 nmol/L)
6-8 years 0.1 – 0.3
(0.3 – 1.0 nmol/L)
8-10 years 0.1 – 0.3
(0.3 – 1.0 nmol/L)
10-12 years 0.3 – 0.7
(1.0 – 2.4 nmol/L)
12-14 years 0.5 – 1.0
(1.7 – 3.5 nmol/L)
> 14 years 0.8 – 2.3
(2.8 – 8.0 nmol/L)
Androstenediol (nanograms per milliliter) 0.2 – 2 ng/ml
Total testosterone - morning sample (nanograms per deciliter or nano-moles per liter) Prepubertal 8 – 14 ng/dl
(0.28 – 0.49 nmol/L)
Pubertal 84 – 480 ng/dl
(2.91 – 6.24 nmol/L)
Adult 300 – 1000 ng/dl
(10.4 – 34.7 nmol/L)
Free testosterone - morning sample (picrograms per milliliter or pico-moles per liter) 20 –40 years 15.0 – 40.0 pg/ml
(520 – 1387 pmol/L)
41 –60 years 13.0 – 35.0 pg/ml
(451 – 1213 pmol/L)
61 –80 years 12.0 – 28.0 pg/ml
(416 – 971 pmol/L)
Dihydrotestosterone (nanograms per milliliter or nano-moles per liter) Prepubertal < 3 – 13 ng/ml
(< 0.1 – 0.4 nmol/L)
Adult 30 – 100 ng/ml
(1.0 – 3.4 nmol/L)
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