Serum macroprolactin levels in pregnancy and association with thyroid autoimmunity.

Metin Guclu,Sinem Kiyici,Gurcan Kisakol,Arif Bayram Hacihasanoğlu,Soner Cander,Ebru Vatansever

doi:10.1186/s12902-015-0025-2

Metin Guclu, Sinem Kiyici + Show 4 more

Open Access

https://doi.org/10.1186/s12902-015-0025-2

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Abstract

BacgroundTo assess the contribution of macroprolactin to high serum prolactin levels and their association with thyroid status and thyroid autoimmunity during pregnancy.Methods138 pregnant women who suspected of having thyroid dysfunction were studied and divided into three groups according to the thyroid status; group 1; euthyroidism (n 40), group 2; hypothyroidism (n 54), and group 3; hyperthyroid (n 44). Polyethylene glycol (PEG) precipitation method was used for detection of macroprolactin. A percentage recovery of 40 % or less is considered as macroprolactinemia. If macroprolactin was negative, the percentage of monomeric prolactin recovery (monoPRL %) after PEG precipitation was used for comparison between the groups.ResultsMacroprolactinemia was found in two patients (1.4 %) one from hypothyroid and other from euthyroid group. Basal prolactin levels in these patients were 400 and 403 ng/mL respectively. Referring to all patients, there was no correlation between PRL, macroPRL or monoPRL % with thyroid hormone status and also with the serum levels of thyroid antibodies (p > 0.05). A positive correlation was observed between the serum levels of PRL with TSH (p = 0.014 and r = 0.219), while a negative correlation was found with FT4 (p = 0.011 and r = −0.227).ConclusionsDespite the fact that serum prolactin levels were found to be high during pregnancy, the contribution of macroprolactin was found to be insignificant in our study. Unlike other auto immune diseases, we could not find any relationship between thyroid autoimmunity and PRL, macroPRL or monoPRL %. These results confirmed that measured prolactin was quite homogeneous during pregnancy.

Highlights

Prolactin, a protein hormone, is secreted from the anterior pituitary usually in response to physiological and rarely pathological stimuli
It is well known that circulating prolactin is not homogenous and three different forms are defined according to molecular size: monomeric PRL, big PRL, and macroprolactin
Macroprolactin is described as a complex of PRL with immunoglobulin G (IgG) which is related to antiprolactin autoantibodies

Summary

Introduction

A protein hormone, is secreted from the anterior pituitary usually in response to physiological and rarely pathological stimuli. Prolactin concentrations begin to increase after 6 weeks of pregnancy and reach the highest level in late pregnancy to prepare the mammary glands of the breasts for the production of milk [1,2,3]. It is well known that circulating prolactin is not homogenous and three different forms are defined according to molecular size: monomeric PRL (monoPRL), big PRL (bigPRL), and macroprolactin (macroPRL). Macroprolactin is described as a complex of PRL with immunoglobulin G (IgG) which is related to antiprolactin autoantibodies. Normal maternal thyroid function is essential for both fetal and maternal health and many physiological alterations occur during pregnancy.

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