Macroprolactin

Macroprolactin is a form of the hormone prolactin that is bound to immunoglobulin G (IgG), making it a larger molecular weight complex. This complex form of prolactin is often biologically inactive or has reduced activity compared to monomeric prolactin.

Biochemistry

Macroprolactin is a complex of prolactin and immunoglobulin G (IgG). Prolactin is a peptide hormone primarily associated with lactation in mammals. The binding of prolactin to IgG alters its size and can affect its biological activity.

Clinical Significance

The presence of macroprolactin can lead to elevated levels of prolactin in blood tests, a condition known as hyperprolactinemia. However, because macroprolactin is often biologically inactive, patients with elevated macroprolactin levels may not exhibit the typical symptoms of hyperprolactinemia, such as galactorrhea, amenorrhea, or infertility.

Diagnosis

The diagnosis of macroprolactin involves measuring serum prolactin levels and then using techniques such as polyethylene glycol (PEG) precipitation to differentiate between monomeric prolactin and macroprolactin. The PEG precipitation test helps to identify the proportion of prolactin that is in the macroprolactin form.

Management

In cases where macroprolactin is identified as the cause of elevated prolactin levels, treatment may not be necessary if the patient is asymptomatic. However, if symptoms of hyperprolactinemia are present, further investigation and management may be required.

Related Pages

• Prolactin
• Hyperprolactinemia
• Immunoglobulin G
• Lactation
• Galactorrhea
• Amenorrhea
• Infertility