This document summarizes information about the hormones oxytocin and prolactin. It discusses where oxytocin is secreted in the body, its actions on mammary glands and the uterus, and its role in milk ejection and childbirth. It also discusses where prolactin is synthesized, its role in lactation, what stimulates its secretion, and the symptoms and causes of hypo- and hyperprolactinemia. Diagnosis and treatment approaches for different prolactin-related conditions are also summarized.

1. Second year – Group B
Morning classes
A presentation by:
Daban Nasih
Nura Omer
Shadiya Najmaddin
Nawzhin Tofiq
Supervised by:
Mrs. Shukrya Karim
Mrs. Daroon Osman
Nursing Department
Academic Year
2022-2023
Oxytocin &
Prolactin
hormones

2. Oxytocin
▶ Source of Secretion:
▶ Secreted mainly by paraventricular nucleus and partly
supraoptic nuclei.
▶ T
ransported from hypothalamusto posterior pituitary
through the nerve fibers of hypothalamo-hypophyseal
tract.
▶ In the posterior pituitary, the oxytocin is stored in the
nerve endings of hypothalamo-hypophyseal tract.
▶ When suitable stimuli reach the posterior pituitary from
hypothalamus, oxytocin is released into the blood.
▶ Oxytocin is secreted in both males and females.

3. ▶ Actiononmammaryglands
▶ Causes ejection of milk from the mammary glands.
▶ Oxytocin causes contraction of the myoepithelial
cellsand flow of milk from alveoli of mammary
glands to the exterior through duct system and
nipple.
▶ The process by which the milk is ejected from alveoli
of mammary glands iscalled milk ejection reflex or
milk letdownreflex.
▶ It isone of the neuro-endocrine reflexes.

4. ▶ ActiononUterus:
▶ Oxytocin actson:
1
. Pregnant uterus
2. Non-pregnant uterus.

5. ⦁ On pregnant uterus:
▶ Throughout the period of pregnancy, oxytocin
secretion isinhibited by estrogen and progesterone.
▶ At the end of pregnancy, the secretion of these two
hormones decreases suddenly and the secretion of
oxytocin increases.
▶ Oxytocin causes contraction of uterus and helps in the
expulsion of fetus.
▶ Itis also an example of neuro-endocrine reflex and
positive feedback mechanism

6. ▶ Onnon-pregnantutreus:
▶Action of oxytocin on non-pregnant uterus is to
facilitate the transport of sperms through female
genital tract up to the fallopian tube, by producing
the uterine contraction during sexual intercourse.

7. Prolactin
⯈Human prolactin is a single- chain polypeptide of
199 amino acids. It has a molecular weight of 23
kDa.
⯈ Prolactinis synthetizedin and secretedfrom
specializedcellsof the anterior pituitary gland, the
lactotrophcells.
⯈ Thepituitary gland(also calledasthe master
gland)is an endocrinegland about the size of apea
(weighing0.5 g)and locatedat the baseof the
brain(just belowthe hypothalamus).

8. FUNCTION
⯈Prolactinis responsibleof:
 Primarily, initiating and sustaininglactation and
 Stimulation of breastdevelopment alongwith Estrogen during pregnancy.

9. Prolactinsecretioniscausedby;
• Prolactin releasinghormone (PRH)
• Estrogen (during stimulates lactotropes to secrete prolactin)
• Oxytocin (causes muscle contractions to expel milk)
• Vasoactiveintestinal peptide(VIP)
• Thyrotropin releasinghormone (TRH)
• Breast feeding
• Stress
• Sleep
• Dopamine antagonists (eg., antipsychotic drugs)
• Chest wall trauma

10. Hypoprolactinemia
⯈ Hypoprolactinemia - decreased prolactin hormone secretion by the anterior pituitary
gland.
⯈ Commoncausesof Hypoprolactinemia:
 Sheehan’ssyndrome
 Hypopituitarism
 Excessdopamine
 Autoimmunedisease
 Growth hormonedeficiency
 Head injury
 Infection
⯈ Symptoms:
 Ovarian diseases,delayedpuberty and infertility.
 Impotenceand abnormal spermatogenesis.

11. Hyperprolactinemia
⯈Hyperprolactinemia– increasedprolactin hormonesecretionbythe anterior pituitary
gland.
⯈ Commoncausesof Hyperprolactinemia:
 Stress
 Medications (e.g,Antipsychoticdrugs)
 Primaryhypothyroidism
 Pituitary glandtumour
 Prolactinoma
⯈ Symptoms:
• Oligomenorrhoea
• Amenorrhoea
• Galactorrhoea
• Infertility
• Hirsutism
• Osteoporosis

12. DIAGNOSIS
⯈Diagnosis:
• History(medication,oligomenorrhoea,hirsutism)
• Physical examination(Galactorrhoea)
• Laboratory
 Pregnancytest
 Prolactin
 Macroprolactin
 TSH, FreeT4
 U& Es
 Tes, LH andFSH
• MRI scan(Prolactinaemia)
• Visualfieldtests (optic nerve)

13. • HyperProlactinaemia:dopamineagonists
(e.g., Bromocryptine orCabergoline)
• Surgeryremovaland/or radiationtherapy
(largepituitary tumours)
• Thyroidabnormalities:thyroid hormone
replacement (e.g., levothyroxine)
• Ovarianinsufficiency:hormonaltherapy
(e.g., Estrogen andprogestins)
TREATMENT