There are many sacrifices involved in being a woman. There are certain standards in the society that people expect us to meet, as well as criticisms in any act we do. But what really is the essence of being a woman? A very familiar question, huh? But there is this one woman who certainly gave a very meaningful answer. She said that the very essence of being a woman is to carry a very precious gift from heaven inside her womb, a child. And I agree with her…
I can relate this to my blog assignment Urinary Estrogen Determination, which is done primarily to help in monitoring the development of the unborn child during pregnancy. Increase in the 24 hour urine output of estrogen is seen as the pregnancy progress. This rise observed over 9 months of pregnancy is due to increase in estriol formation. There are several methods used in the determination of urinary estrogen, these includes Kober reaction, Preedy and Aitkin (fluorometric), Brown and Ittrich. But only Kober reaction will be discussed in this post.
SPECIMEN:
A 24-hour urine specimen
PROCEDURE:
KOBER REACTION (Colorimetric Method)
Preceding estrogen analysis, the sample is checked first for glucose concentration because high levels of any compound forming acetaldehyde will produce false negative results by reacting with hydroquinone. Then procedure involves heating a urine sample in a strong aqueous sulfuric acid solution containing hydroquinone. After cooling and dilution, the absorbance of the resulting reddish-brown color is measured and total estrogen concentration determined.
Hydrolysis of estrogen conjugates is accomplished with HCl and heat or enzymatically. Extraction into ethyl acetate separates the steroids from other materials. After drying to remove the organic solvent, a mixture of hydroquinone and sulfuric acid is added to the tube containing the estrogens. The tubes are heated to produce the color. Absorbance is determined at 472, 512, and 556 nm, followed by an Allen correction to calculate the estrogen concentration using standard solutions for calibration.
The KOBER REACTION colorimetric assay has sensitivity enough to quantitate total urine estrogens during pregnancy. Slight alteration of the procedure allows fluorometric assays with good sensitivity and accuracy for specimens from nonpregnant women.
Meprobamate, L-dopa, and phenolphthalein all give reactions with the Kober reagent, falsely increasing the results for urine total estrogen output.
NORMAL VALUE:
· Total estrogens excretion in the urine range from 4 to 100 ug /day
(This depends on the phase of menstrual cycle)
· During pregnancy estrogen production rates rise markedly, reaching levels grater than 40 mg/24 hours at term, close to a 500-folds increase over non-pregnant rates.
(This increased synthesis in cause by joint participation of mother and child in the biochemical production of estrogens.)
Note: Significant decrease in urine estrogen output occurs in patients taking ampicillin or neomycin. These antibiotics reduce bacterial levels in the intestine, causing a diminished hydrolysis of estriol conjugates. The re-uptake of estriol into the circulation becomes impaired, as is the urine excretion of estrogens. Hydrochlorothiazide produces falsely lowered results due to its destruction of estrogens during the acid
CLINICAL SIGNIFICANCE:
Below are conditions where one might see an increase or decrease of estrogen levels.
Increased levels of estrogens are seen in:
- Normal menstrual cycle
- Early (precocious) puberty
- Gynecomastia
- Tumors of the ovary, testes, or adrenal glands
- Hyperthyroidism
- Cirrhosis
Decreased levels of estrogen are seen in:
- Turner syndrome
- Hypopituitarism
- Hypogonadism
- Failing pregnancy (estriol)
- Eating disorder anorexia nervosa
- After menopause (estradiol)
- PCOS (Polycystic ovarian syndrome, Stein-Levanthal syndrome)book by Dio
- Extreme endurance exercise
Reference: Clinical Chemistry: A Fundamental Text Book by Donald Calbreath
