Prolactin

Compartilhe esta página
Imprimir este artigo
Esta página foi útil?
Também chamado: PRL
Nome formal: Prolactin
Exames relacionados: FSH, LH, Testosterone, DHEAS, Estrogen, Progesterone

De relance

Por que fazer este exame?

To determine whether your prolactin levels are higher (or occasionally, lower) than normal

Quando fazer este exame?

When you have symptoms of elevated prolactin, such as galactorrhea and/or visual disturbances and headaches; as part of a workup for female and male infertility; for follow-up of low testosterone in men

Amostra:

A blood sample drawn from a vein in your arm

A amostra

O que está sendo pesquisado?

Prolactin is a hormone produced by the anterior pituitary gland, a grape-sized organ found at the base of the brain. Prolactin levels are regulated by dopamine (a brain chemical), and the hormone is normally present in low amounts in men and non-pregnant women. Its primary role is to promote lactation (breast milk production).

Prolactin levels are usually high throughout pregnancy and just after childbirth. During pregnancy, prolactin, estrogen, and progesterone stimulate breast milk development. Following childbirth, prolactin helps initiate and maintain the breast milk supply. If a woman does not breastfeed, her prolactin soon drops back to low pre-pregnancy levels. If she does nurse, suckling by the infant plays an important role in the release of prolactin. There is a feedback mechanism between how often the baby nurses and the amount of prolactin secreted by the pituitary as well as the amount of milk produced. Prolactin levels will continue to be high while the mother continues to nurse, but will eventually fall back to pre-pregnancy levels.

Besides pregnancy, the most common cause of elevated prolactin levels is a prolactinoma, a prolactin-producing tumor of the pituitary gland. Prolactinomas are the most common type of pituitary tumor and are usually benign. They develop more frequently in women but are also found in men. Problems from them can arise both from the unintended effects of excess prolactin, such as milk production in the non-pregnant woman (and rarely, man) and from the size and location of the tumor.

If the anterior pituitary gland and/or the tumor enlarge significantly, it can put pressure on the optic nerve, causing headaches and visual disturbances, and it can interfere with the other hormones that the pituitary gland produces. In women, prolactinomas can cause infertility and irregularities in menstruation; in men, these tumors can cause a gradual loss in sexual function and desire. If left untreated, prolactinomas may eventually damage the tissues around them.

Como a amostra é obtida para o exame?

A blood sample is obtained by inserting a needle into a vein in the arm.

NOTA: Se exames médicos em você ou em alguém importante para você o deixam ansioso ou constrangido, ou se você tem dificuldade de lidar com eles, leia um ou mais dos seguintes artigos: Lidando com dor, desconforto ou ansiedade durante o exame, Conselhos sobre exames de sangue, Conselhos para ajudar crianças durante exames médicos, and Conselhos para ajudar idosos durante exames médicos.

Outro artigo, Siga essa amostra, fornece uma visão da coleta e do processamento de uma amostra de sangue e de uma amostra de cultura da garganta.

O exame

Perguntas frequentes

Pergunte ao laboratório

* indica um campo necessário



Por favor, indique se você é:   
  
  



Você deve fornecer um endereço de e-mail válido para receber uma resposta.



| |

Fontes do artigo

« Voltar para páginas relacionadas

NOTA: Este artigo se baseia em pesquisas que incluíram as fontes citadas e a experiência coletiva de Lab Tests Online Conselho de Revisão Editorial. Este artigo é submetido a revisões periódicas do Conselho Editorial, e pode ser atualizado como resultado dessas revisões. Novas fontes citadas serão adicionadas à lista e distinguidas das fontes originais usadas.

S1
Thomas, Clayton L., Editor (1997). Taber’s Cyclopedic Medical Dictionary. F.A. Davis Company, Philadelphia, PA [18th Edition].

S2
Pagana, Kathleen D. & Pagana, Timothy J. (2001). Mosby’s Diagnostic and Laboratory Test Reference 5th Edition: Mosby, Inc., Saint Louis, MO.

S3
Merck. Anterior Pituitary Function [6 paragraphs]. The Merck Manual of Diagnosis and Therapy [On-line information]. Available FTP: http://www.merck.com/pubs/mmanual/section2/chapter6/6c.htm

S4
(2002 February 17 Updated). Prolactin [12 paragraphs]. MEDLINEplus Health Information [On-line information]. Available FTP: http://www.nlm.nih.gov/medlineplus/ency/article/003718.htm

S5
(2002 July 24, Updated). Prolactinoma – males [10 paragraphs]. MEDLINEplus Health Information [On-line information]. Available FTP: http://www.nlm.nih.gov/medlineplus/ency/article/000337.htm

S6
Pituitary: Overview [15 paragraphs]. The Hormone Foundation [On-line information]. Available FTP: http://www.hormone.org/learn/pituitary_1.html

S7
Pituitary: Secretory Tumors [19 paragraphs]. The Hormone Foundation [On-line information]. Available FTP: http://www.hormone.org/learn/pituitary_2.html

S8
Prolactin test [13 paragraphs]. Hendrick Health System, AccessMed Health Information Library [On-line information]. Available FTP: http://www.hendrickhealth.org/healthy/00062060.html

S9
ARUP. Prolactin [5 paragraphs]. ARUP’s Guide to Clinical laboratory Testing [On-line information]. Available FTP: http://www.aruplab.com/guides/clt/tests/clt_150b.htm#1145504

S10
Merck. General [3 paragraphs]. The Merck Manual of Diagnosis and Therapy, Section 2. Endocrine And Metabolic Disorders, Chapter 6. Hypothalamic-Pituitary Relationships [On-line information]. Available FTP: http://www.merck.com/pubs/mmanual/section2/chapter6/6a.htm

S11
Grunebaum, A. (2001 April 23). A Tiny Gland's Big Role in Pregnancy [11 paragraphs]. WebMD Health Information [On-line information]. Available FTP: http://my.webmd.com/content/article/3607.442

S12
The Impotence Sourcebook (1998). Laboratory Investigations of Erectile Dysfunction [13 paragraphs]. WebMD Health Information [On-line information]. Available FTP: http://my.webmd.com/content/article/1680.50141

S13
Spengler, R. (2001 February 22, Updated). Prolactin [24 paragraphs]. WebMD Health Information [On-line information]. Available FTP: http://my.webmd.com/printing/article/4118.253

S14
Harrison's Principles of Internal Medicine, Kasper, et al, 16th Edition, McGraw Hill, 2005, pg 2084.