- This is done on the serum of the patient.
- The patient needs to be fasting for 12 hours.
- Take the blood sample after 3 to 4 hours of the wake from sleep because:
- The level rises during the deep sleep.
- There is a peak in the early morning hours.
- The sample may be stored at 4 °C for 24 hours.
- For a long time can freeze the sample.
- In case of borderline elevation of PRL:
- Repeat the estimation at least two times at some interval.
- Take the sample in the morning.
- Avoid excitement in the patient.
- Avoid breast stimulation and no trauma.
- No medication which can stimulate the PRL release like:
- Dopamine antagonists (metoclopramide, domperidone, haloperdol).
- Advise TSH in such cases where primary hypothyroidism, can elevate PRL.
- Take a sample in the morning between 8 to 10 AM after at least 3 to 4 hours of the wake.
- It increases during sleep and peak level is in the early morning.
- When collecting the sample, avoid emotional stress, exercise and protein ingestion, all of these increase the prolactin level.
- In the case of the borderline raised level, advise estimation two more times and avoid breast stimulation, no trauma, and no interfering medication.
- Diagnose prolactin-producing tumors, like pituitary adenoma.
- Use to monitor the prolactin-producing tumors.
- Used for secondary amenorrhoea or galactorrhea, infertility, and hyperprolactinemia.
- Useful for the hypothalamic disease.
- Monitor the effectiveness of surgery, chemotherapy, and radiation in prolactin-producing tumors.
- The main function of Prolactin is to initiate and maintain the lactation.
- This is a lactogenic hormone synthesized by the pituitary gland.
- Prolactin induces ductal growth, develops lobular system and synthesis of milk production.
- Prolactin is an anterior pituitary hormone for initiating and maintaining the lactation.
- It is 32 kD and is synthesized as preprolactin.
- Prolactin release is stimulated by suckling and suppressed by stress.
- Until puberty, both males and females have the same level.
- Estrogen level gives rise to an increase in the prolactin level in females.
- Prolactin secretion is controlled by the:
- prolactin-inhibiting hormone, which is dopamine.
- Prolactin-releasing factor (PRF), which is a thyrotropin-releasing hormone (TRH).
- Dopamine controls the prolactin secretion. When more dopamine then less prolactin.
- ACTH is increased with stress, leads to elevation of the PRL level.
- Last is the PRL feedback loop between the pituitary and hypothalamus.
- During sleep prolactin level increase 2 to 3 times.
- Prolactin has receptors on the target organs like the breast, adrenal glands, ovaries, testes, prostate, and liver.
- Prolactin has various functions in the body and these are summarized as follows.
- PRL like other hormones has a receptor on the cell membrane of target organs like breast, uterus, adrenal gland, testes, ovary, kidney, and liver.
- Increased prolactin level is seen in :
- Breast stimulation.
- Pituitary tumors form acidophilic cells that produce prolactin.
- The moderate level increase is seen in :
- Secondary amenorrhea.
- primary hypothyroidism.
- Polycystic ovary syndrome.
|Coed blood||45 to 539|
|Newborn 1 to 7 days||30 to 495|
|Children Tanner stage||Male||Female|
|1||<10||3.6 to 12|
|2 to 3||<6.1||2.6 to 18|
|4 to 5||2.8 to 11.0||3.2 to 20|
|3.0 to 14.7||3.8 to 23.2|
3rd trimester= 95 to 473
- To convert into SI unit x 1.0 = µg/L
- Tanner stage is the physical scale of development of primary and secondary sex characteristics.
- Adult male = 0 to 20 ng/mL
- Adult female = 0 to 25 ng/mL
- Pregnant female = 20 to 400 ng/mL
|Nonpregnant women||0 to 23 ng/mL|
|Pregnant women||34 to 386 ng/mL|
|Pregnancy 1st trimester||<80 ng/mL|
|Pregnancy 2nd trimester||<169 ng/mL|
|Pregnancy 3rd trimester||<400 ng/mL|
|Men||0 to 20 ng/mL|
|Children||3.2 to 20 ng/mL|
Increased prolactin level is seen in:
- Diseases of the hypothalamus and pituitary gland.
- Prolactin-secreting pituitary tumors.
- Galactorrhea and amenorrhea.
- Paraneoplastic syndrome when there is Ectopic production from lung cancers, other tumors, and leukemia.
- Polycystic ovary.
- Anorexia nervosa.
- Adrenal insufficiency.
- Metastatic cancer of the pituitary gland.
- Chronic Renal failure.
Decreased Prolactin level is seen in:
- Sheehan’s syndrome (after delivery may have hemorrhage or infarction of the pituitary gland).
- Pituitary destruction by the tumors e.g. Craniopharyngioma.
Hyperprolactinemia leads to in:
- Anovulation With or without irregularity in menstruation.
- Galactorrhea and amenorrhea.
- Or galactorrhea alone.
- In Males
- May have impotence.
- Or both.
- Men with PRL secreting pituitary adenoma mostly have a presentation of macroadenoma and visual disturbance because of large tumor size pressing on the optic chiasma.
- 30% of the microadenoma patients have a clinically silent tumor. But the PRL level will be raised.
- Imaging like CT or MRI is advised.
- Patients with >150 ng/mL have PRL secreting tumors.
- Many patients have >1000 ng/mL of PRL.
- PRL level >200 ng/mL is enough evidence for PRL-secreting pituitary tumors.