Monday, June 1, 2009

Luteinizing Hormone

Luteinizing Hormone a.k.a. Lutropin. It is a hormone that is produced by the anterior pituitary gland. They are under complex regulation by hypothalamic gonadotropin-releasing hormone and by gonadal sex hormones (estrogen and progesterone in females and testosterone in males). Luteinizing hormone acts on Leydig's (interstitial) cells of the gonads. For females, an acute rise of LH will trigger the ovulation, while for males, where LH had also been called Interstitial Cell Stimulating Hormone (ICSH), wherein it stimulates Leydig cell the production of testosterone which stimulates and maintains spermatogenesis. This steroid hormone is synthesized from cholesterol in the testes and is the principal androgen. It is lipid soluble and readily diffuses out of Leydig cell into the interstitial fluid and then into the blood. Testosterone acts in a negative feedback manner to suppress secretion of LH by anterior pituitary gonadotrophs and to suppress secretion of GnRH by hypothalamic neurosecretory cells. In some target cells, such as those in the prostate and seminal vesicles, the enzyme 5 alpha-reductase converts testosterone to another androgen called dihydrotestosterone (DHT).

Purpose for testing
○ To detect ovulation
○ To assess male or female infertility
○ To evaluate amenorrhea
○ To monitor therapy designed to induced ovulation



Reference values for LH:
♀Female
Follicular ------------------------- 1.37 to 9.9 mIU/L
Ovulatory peak ------------------ 6.17 to 17.2 mIU/L
Luteal ---------------------------- 1.09 to 9.2 mIU/L

Postmenopausal ----------------- 19.3 to 100.6 mIU/L
♂Male -------------------------- 1.42 to 15.4 mIU/L



Procedure and posttest care
♦ Perform a venipuncture, and collect the sample in a 7-ml clot-activator tube.
♦ Apply direct pressure to the venipuncture site until bleeding stops.
♦ If a hematoma develops at the venipuncture site, apply warm soaks.
♦ Instruct the patient that he/she may resume medications discontinued before tests as ordered.



Precautions
• Handle the sample gently to prevent hemolysis.
• If the patient is a female, indicate the phase of her menstrual cycle on the laboratory request. Make a note if the patient is menopausal.



Abnormal Findings
In women, absence of a mid-cycle peak in plasma LH levels may indicate anovulation. Decreased or low-normal plasma may indicate hypogonadism; these findings are commonly associated with amenorrhea. High plasma LH levels may indicate congenital absence of ovaries or ovarian failure associated with Stein-Leventhal syndrome (polycystic ovary syndrome), Turner's syndrome (ovarian dysgenesis), menopause or early stage acromegaly. Infertility can result from primary or secondary gonadal dysfunction.
In men, low plasma LH values may indicate secondary gonadal dysfunction (of hypothalamic or pituitary origin); high values may indicate testicular failure (primary hypogonadism) or destruction or congenital abscence of testes.


Interfering factors
◘ Recently administered radioisotopes.
◘ Hemolysis of blood sample.
◘ Estrogen or oral contraceptives, testosterone.
◘ Several drugs affect test outcome.
◘ Pregnancy.






References:

☺A Manual of Laboratory and Diagnostic Tests 7th Edition
by Frances Fischbach

☺Professional Guide to Diagnostic Tests

☺Clinical Chemistry Principles, Procedures, Correlations 5th Edition
by Michael L. Bishop, Edward P. Fody, Larry E. Schoeff

☺Principles of Anatomy and Physiology 10th Edition
by Gerard Tortora, Sandra Reynolds Grabowski

☺http://en.wikipedia.org








14 comments:

Anjelica Naguiat said...

hello my. this is wonderful! i enjoyed reading your article, especially that you can press the hyperlinked word and you will know what it means! nice one brotha! looking forward to your next post.:)

♥XOXO

eryLL said...

pwede na comment! haha
your post was really interesting.

eryLL said...
This comment has been removed by the author.
Jena Isle said...

Good post. Follow the rest of the suggestions.

Unknown said...

great post mr. myron espiritu. very informative.

zorlone said...

I agree with katlin. This is an informative post. Just enough to get by LH. Since you are a med tech, the important portion is how to collect and analyze the samples for each tests.

Good job!

Zorlone

Anonymous said...

i just read your blog and it was really helpful to your co-medtech students. job well done!

zorlone said...

My bad, the last sentence should said, "Since you are a med tech, the important portion is how to collect and analyze the samples for each test."

Apologies to my grammar.

Zorlone

eryLL said...

your post MOVES me!! good work.

KristineKretel said...

it was a well explained post..
i love the moving parts!hehe
keep it up!

KristineKretel said...

it was a well explained post..
i must say that i love the moving parts!!
keep it up!

ann alexys said...

your post is informative and easy to understand. good job!

Kelly said...

very informative post keep it up. you can add the procedure/ method for
the identification of lh in the body. bur overall good job. keep it up

maricris said...

good post i agree with others that it is very impormative for the readers and the post is very simplify,,. keep it up..,,,