Asymptomatic 'big' hyperprolactinemia in two men with pituitary adenomas

Tritos, Nicholas A.; At, Guay; Malarkey, W.B.

doi:10.1530/eje.0.1380082

Cited by 31 publications

(16 citation statements)

References 19 publications

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“…Similar to macroprolactin, big prolactin is also reported to lack biological activity in vivo (12,29,30 ). Although the physiochemical nature of big prolactin is unclear, the immunoassay reactivity appears similar to that of macroprolactin.…”

Section: Discussionmentioning

confidence: 97%

Specificity and Clinical Utility of Methods for the Detection of Macroprolactin

et al. 2006

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Background: Increased serum concentrations of macroprolactin are a relatively common cause of misdiagnosis and mismanagement of hyperprolactinemic patients. Methods: We studied sera from a cohort of 42 patients whose biochemical hyperprolactinemia was explained entirely by macroprolactin. Using 5 pretreatments, polyethylene glycol (PEG), protein A (PA), protein G (PG), anti-human IgG (anti-hIgG), and ultrafiltration (UF), to deplete macroprolactin from sera before immunoassay, we compared residual prolactin concentrations with monomer concentrations obtained by gel-filtration chromatography (GFC). A monomeric prolactin standard was used to assess recovery and specificity of the pretreatment procedures. Results: Residual prolactin concentrations in all pretreated sera differed significantly (P <0.001) from monomeric concentrations obtained after GFC. PEG underestimated (mean, 75%), whereas PA, PG, anti-hIgG, and UF overestimated (means, 178%, 151%, 178%, and 112%, respectively) the amount of monomer present. Of the 5 methods examined, PEG correlated best with GFC (r ‫؍‬ 0.80) followed by PG (r ‫؍‬ 0.78), PA (r ‫؍‬ 0.72), anti-hIgG (r ‫؍‬ 0.70), and UF (r ‫؍‬ 0.61). After UF or pretreatment with anti-hIgG or PEG, recovery of monomeric prolactin standard was low: 60%, 85%, and 77% respectively. In contrast, pretreatment with PA or PG gave almost quantitative recovery. Conclusions: None of the methods examined yielded results identical to the GFC method. PEG pretreatment

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Section: Discussionmentioning

confidence: 97%

Specificity and Clinical Utility of Methods for the Detection of Macroprolactin

et al. 2006

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“…13`B ig' and big ± big' PRL (macroprolactinemia) do not appear to contribute to ED. 14,15 For this reason, Cavaco et al suggest PRL measuring methods which are less sensitive to the presence of`big ± big' PRL in order to differentiate clinically important HP from that caused by macroprolactinemia. 16 The assay used to measure PRL in this study could not exclude macroprolactinemia and was unable to identify which PRL variant was being measured.…”

Section: Discussionmentioning

confidence: 99%

Severe erectile dysfunction is a marker for hyperprolactinemia

2001

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The need for routine prolactin (PRL) measurement in the initial evaluation of erectile dysfunction (ED) has been questioned because of the low rate of hyperprolactinemia (HP) in these men and the costs involved. In addition, it is widely thought that sexual desire problems are a good clinical marker for HP andaor low testosterone in men with ED. Within a 15-month period, 844 consecutive PRL and sexual hormone determinations were conducted in men at the Kingston General Hospital. Of these patients, 138 were comprehensively evaluated at the ®rst visit for ED and completed the International Index of Erectile Function (IIEF). In the 138 patients, 2.2% had severe hyperprolactinemia (b35 ngaml), within the range of 1 ± 5% previously reported. No correlation between initial prolactin value and the sexual desire domain or the erectile function domain (EFD) of the IIEF was found for this population. However, all cases of severe HP were found to occur in men who scored less than 10 in the EFD of the IIEF. Low libido is widely accepted as a marker of HP. In this study, HP was found in patients not reporting major problems with a desire disorder. Clinically signi®cant HP may be reliably found with routine biochemical evaluation and in this series was not detected in patients with EFD scores above 10. A routine PRL measurement is inexpensive and early detection of a serious and treatable disease may afford greater therapeutic success.

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“…The prevalence of macroprolactin is unknown although it may be more frequent than previously thought [4, 5]. Most of the patients with macroprolactin lack symptoms directly associated with the hyperprolactinemic syndrome, however clinical management of this condition is controversial [6, 7, 8]. …”

Section: Introductionmentioning

confidence: 99%

Prevalence of Macroprolactin Detected by Elecsys<sup>®</sup> 2010

Sánchez-Eixerés

Maurí²,

Alfayate³

et al. 2001

Horm Res Paediatr

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Background: Macroprolactin or big-big PRL is, usually, a complex of little prolactin (PRL) with anti-PRL autoantibody. There are some patients with hyperprolactinemia showing a high proportion of serum macroprolactin. However, its clinical significance is not clear. Immunoassays used to determine PRL differ in their ability to detect macroprolactin. Moreover, in recent years, PRL assays have changed from isotopic methods (radioimmunoassays and immunoradiometric assays) to non-isotopic automated immunoassays. The effect of macroprolactin on currently used methods is often unknown. The aim of this work was to study the different reactivity of macroprolactin in two immunoassays systems, Elecsys 2010 and ACS Centaur, and to assess the clinical repercussion of this condition. Methods: We studied retrospectively 956 consecutive routine patients. Samples with a PRL value >636 mIU/l (211 samples) were subjected to the polyethylene glycol (PEG) precipitation test to detect macroprolactin, and 2 of them also to gel filtration chromatography for further confirmation. PRL was measured by Elecsys 2010 and, alternatively, by ACS Centaur. Results: By Elecsys 2010, macroprolactin was detected in 19 patients (9%). After removing macroprolactin, PRL levels were within the normal range in every case but one. When original sera from patients with macroprolactin were processed with ACS Centaur. PRL levels were normal or only marginally elevated. The correlation of PRL values in samples with and without macroprolactin assayed by both systems was 0.64 and 0.98, respectively. Conclusions: Nearly 9% of hyperprolactinemic patients detected by Elecsys 2010 may have macroprolactin, but the detection rate obtained using ACS Centaur is much lower. As macroprolactin seems to have minimal clinical relevance, it would be important that the users of PRL assays be aware to what extent macroprolactin interferes with their assays, and have available a validated method, such as the PEG precipitation test, to confirm the presence of macroprolactin.

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Asymptomatic 'big' hyperprolactinemia in two men with pituitary adenomas

Cited by 31 publications

References 19 publications

Specificity and Clinical Utility of Methods for the Detection of Macroprolactin

Specificity and Clinical Utility of Methods for the Detection of Macroprolactin

Severe erectile dysfunction is a marker for hyperprolactinemia

Prevalence of Macroprolactin Detected by Elecsys<sup>®</sup> 2010

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