Endocrine Abstracts

Macroprolactin, a circulating complex of monomeric prolactin together with an autoantibody, is commonly encountered in the course of endocrine investigations. It is generally agreed macroprolactin exhibits reduced bioactivity in vivo since individuals who harbour the complex do not demonstrate the classic clinical signs or symptoms characteristic of true hyperprolactinaemia. The aim of this study was to compare the relative potency of purified preparations of macroprolactin to...

Where screening for macroprolactin takes place, laboratories routinely rely on treatment of sera with polyethylene glycol (PEG) to distinguish macroprolactinaemia from true hyperprolactinaemia. However, PEG is incompatible with a number of common immunoassay platforms. The aim of this study was to assess the specificity and clinical utility of ultrafiltration as an alternative procedure for removal of bio-inactive prolactin IgG complexes such as macroprolactin from serum prior...

Macroprolactin has reduced bioactivity and accumulates in the sera of some subjects, resulting in apparent hyperprolactinaemia. Development of the polyethyleneglycol (PEG) precipitation technique has enabled large-scale screening for macroprolactin in hyperprolactinaemic subjects. We have reviewed the experience of routine screening for macroprolactin using PEG precipitation over a 54-month period in a single centre.Plasma levels of prolactin exceeded 50...

The importance of the differentiation between the apparent benign clinical condition of macroprolactinaemia and that of true hyperprolactinaemia, which requires therapy, is becoming widely recognised. Laboratories routinely rely on prolactin recoveries of less than 40 percent following treatment of sera with polyethylene glycol (PEG) to distinguish between the former and latter conditions. However, the 40 percent threshold employed is arbitrarily defined with little scientific...

Macroprolactin, a high molecular mass complex of prolactin and an IgG antibody is confined to the vasculature and exhibits limited bioactivity in vivo. Using a panel of sera obtained from 10 subjects whose hyperprolactinaemia was due entirely to macroprolactin this study aims to compare the level of detection of macroprolactin by 9 of the most commonly used prolactin immunoassays.The study involved 24 clinical laboratories employing the following 9 anal...

The adrenal cortex produces aldosterone, cortisol and adrenal androgens. ACTH regulates the production of both cortisol and adrenal androgens. However there are physiological and pathophysiological conditions where the production of these steroids is divergent. We examined the effect angiotension II (A-II) and insulin on the relative production of cortisol and adrenal androgens in the human adrenal H-295 cell line. We determined the ability of these secretogogues to regulate t...

The adrenal cortex produces aldosterone, cortisol and adrenal androgens in response to secretogogues including ACTH, angiotensin II(A-II) and insulin. Differential regulation of adrenal steroids is through the modulation of specific key steroidogenic enzymes. The capacity of the adrenal to produce cortisol is controlled in part by the transcription of 3beta-hydroxysteroiddehydrogenase (3beta HSD) and production of adrenal androgens by 17 hydroxylase/17-20 lyase (CYP17). Protei...

Introduction: We present a 5-year-old girl with thyroid hormone resistance, subsequently discovered to be heterozygous for TRβ mutation. This case highlights the necessity to investigate, in detail, all children with persistently high thyroxin with normal TSH levels in order to aid future management and the necessity to follow them up.Case report: SD was born at term by normal delivery weighing 3.34 kg (50th centile). She was referred at 6 months of...

Where screening for macroprolactin takes place, laboratories routinely rely on treatment of sera with polyethylene glycol (PEG) to distinguish macroprolactinaemia from true hyperprolactinaemia. However, PEG causes significant interference in some immunoassays and furthermore leads to co-precipitation of a variable amount of monomeric prolactin in addition to macroprolactin in treated sera. The aim of this study was to assess the specificity and clinical utility of alternative ...

IntroductionLow Bone Mineral Density (BMD) is highly prevalent in adults with cystic fibrosis (CF) and is associated with increased fracture rates. We sought to establish how BMD changes with time in adults with CF and to determine what factors influence this change.MethodsA retrospective analysis of interval bone densitometry using Dual Energy X-ray Absorptiometry (DXA) scanning in 86 adults with CF was unde...