Human Prolactin ELISA Kit

INTENDED USE

This Human Prolactin ELISA Kit is to be used for the in vitro quantitative determination of human Prolactin concentrations in serum.  This kit is intended FOR LABORATORY RESEARCH USE ONLY and is not for use in diagnostic or therapeutic procedures.

INTRODUCTION

Human Prolactin (lactogenic hormone) is secreted from the anterior pituitary gland in both men and women.  Human Prolactin is a single chain polypeptide hormone with a molecular weight of approximately 23,000.  The release and synthesis of Prolactin is under neuroendocrinal control, primarily through Prolactin Releasing Hormone and Prolactin Inhibiting Hormone.

Women normally have slightly higher basal Prolactin levels than men.  Apparently, there is an estrogen-related rise at puberty and a corresponding decrease at menopause.  The primary functions of Prolactin are to initiate breast development and to maintain lactation.  Prolactin also suppresses gonadal function.  During pregnancy, Prolactin levels increase progressively to between 10 and 20 times normal values, declining to non-pregnant levels by 3-4 weeks post-partum.  Breast-feeding mothers maintain high levels of Prolactin, and it may take several months for serum concentrations to return to non-pregnant levels.

The determination of Prolactin concentration is helpful in diagnosing hypothalamic-pituitary disorders. Microadenomas (small pituitary tumors) may cause hyperprolactinemia, which is sometimes associated with male impotence.  High Prolactin levels are commonly associated with galactorrhea and amenorrhea.  Prolactin concentrations have been shown to be increased by estrogens, thyrotropin-releasing hormone (TRH), and several drugs affecting dopaminergic mechanisms.  Prolactin levels are elevated in renal disease and hypothyroidism, and in some situations of stress, exercise and hypoglycemia.  Additionally, the release of Prolactin is episodic and demonstrates diurnal variation.  Mildly elevated Prolactin concentrations should be evaluated taking these considerations into account.  Prolactin concentrations may also be increased by drugs such as chloropromazine and reserpine and may be lowered by bromocriptine and L-dopa.

PRINCIPLE OF THE ASSAY

This Prolactin enzyme linked immunosorbent assay (ELISA) applies a technique called a quantitative sandwich immunoassay.  The microtiter plate provided in this kit has been pre-coated with a monoclonal antibody specific for Prolactin.  Standards or samples are then added to the microtiter plate wells and Prolactin if present, will bind to the antibody pre-coated on the wells.  In order to quantitate the amount of Prolactin present in the sample, a standardized preparation of horseradish peroxidase (HRP)-conjugated monoclonal antibody, specific for Prolactin are added to each well to “sandwich” the Prolactin immobilized on the plate.  The microtiter plate undergoes incubation, and then the wells are thoroughly washed to remove all unbound components.  Next, a TMB (3,3',5,5' tetramethyl-benzidine) substrate solution is added to each well.  The enzyme (HRP) and substrate are allowed to react over a short incubation period.  Only those wells that contain Prolactin and enzyme-conjugated antibody will exhibit a change in colour.  The enzyme-substrate reaction is terminated by the addition of a sulphuric acid solution and the colour change is measured spectrophotometrically at a wavelength of 450 nm.

In order to measure the concentration of Prolactin in the sample, this Human Prolactin ELISA Kit includes a set of calibration standards (6 standards).  The calibration standards are assayed at the same time as the samples and allow the operator to produce a standard curve of Optical Density (O.D.) versus Prolactin concentration (ng/mL).  The concentration of Prolactin in the samples is then determined by comparing the O.D. of the samples to the standard curve.

CITATIONS

1. Tsinzerling N et al. Raised prolactin levels in myasthenia gravis: two case reports and a study of two patient populations.  Acta Neurol Scand. 2006 Nov;114(5):346-9.

2. Q Xu et al. Isolation of tumour stem-like cells from benign tumours. Br J Cancer. Jul 21, 2009; 101(2): 303–311.