Prolactin (PRL) plays a role in innate and adaptive immunity. There are important connections between the immune and the endocrine systems. PRL is produced in the anterior pituitary gland and by immune cells. PRL receptors are found in many parts of the body.
The primary role of PRL is to control the growth of mammary and ovarian tissue. PRL is one of the hormones of the hypothalamo-pituitary-adrenal (HPA) axis, important for stress response. PRL is antiangiogenic, vasoconstrictive and promotes vascular regression. Low dose PRL is inflammatory; high dose PRL is anti-inflammatory. PRL helps the immune system recover from chemotherapy.
Hyperprolactinemia (high blood prolactin level,) or hyperprolactinaemia, can cause male or female infertility. Hyperprolactinemia has been identified in autoimmune diseases, such as rheumatoid arthritis (6-40%), systemic lupus erythematosis (SLE) (20-40%), Sjogren’s syndrome (16-46%), polymyositis (24%), psoriasis arthritis, celiac disease, type 1 diabetes mellitus, lymphocytic hypophysitis, Addison’s disease, Grave’s disease, Hashimoto’s thyroiditis, multiple sclerosis and systemic sclerosis (13-59%).
A number of people have been found to have prolactin secreting prolactinoma tumors and SLE. This may point to the role of prolactin in SLE. Some SLE patients have anti-PRL antibodies, reducing the effects of the PRL and the clinical symptoms. SLE patients demonstrate the relationship between PRL and autoimmune disease. Dopamine agonist use, to reduce prolactin levels, has had few studies. The studies of SLE support the use of dopamine agonists during pregnancy and during the postpartum period. Certain cases of SLE have benefited from vitamin D treatment.
CONCLUSION: There is abundant evidence that PRL has an “immunostimulatory effect and promotes autoimmunity.” Further studies are needed to determine the effect of dopamine agonists as agents of anti-prolactinemia in autoimmune diseases.
NOTE: Dopamine agonists reduce prolactin levels. Dopamine agonists include the following: phenylalanine, tyrosine and Vitex agnus casti (vitex or chasteberry.) Boswellia serrata has 5-lipoxygenase inhibitor activity, which reduces prolactin levels. Read about the ability of of vitex to shrink a prolactinoma (a prolactin secreting pituitary tumor.
To read the author’s abstract of the article click on the link to the author’s title of the article above.
PMID: 19911311.
Summary #361.

