Korean J Lab Med.  2009 Apr;29(2):104-109. 10.3343/kjlm.2009.29.2.104.

The Comparison of Parathyroid Hormone Degradation Effect by Various Protease Inhibitors in Blood Specimen

• Kim YS
• Kwon HJ
• Lee HK

• KMID: 854965
• DOI: http://doi.org/10.3343/kjlm.2009.29.2.104

Abstract

BACKGROUND
The objective of this study was to evaluate the role of proteases on the degradation of parathyroid hormone (PTH) in blood samples. METHODS: Protease inhibitors with specificity against serine proteases (aprotinin), cysteine proteases (E-64), serine and cysteine proteases (leupeptin), metalloproteases (EDTA), or a protease inhibitor cocktail with a broad spectrum of inhibitory activity were added to blood samples. After storage at room temperature (0-48 hr), PTH levels were measured. RESULTS: PTH levels in samples with the protease inhibitor cocktail did not change significantly after 48 hr of storage at room temperature, but the average PTH levels decreased by 40.7% and 20.1%, in samples stored at room temperature and stored at 4degrees C without protease inhibitors, respectively. PTH levels in samples with leupeptin were stable for up to 24 hr. After 48 hr, the mean PTH levels decreased by 17.1%, 16.0%, 26.2%, and 32.1%, with 500 KIU/mL aprotinin, 100 micro mol/L leupeptin, 10 micro mol/L E-64, and 10 micro mol/L EDTA, respectively, in the samples stored at room temperature. CONCLUSIONS: The decrease in PTH levels in blood samples seemed to be due to the degradation of PTH by proteases. Various proteases, including especially serine proteases, would act together to degrade PTH in blood specimen. The PTH degradation may be inhibited in blood specimen with protease inhibitor cocktail.

Keyword

Metal ion; Serine proteases; Parathyroid hormone

MeSH Terms

Aprotinin/pharmacology
Blood Specimen Collection
Edetic Acid/pharmacology
Female
Humans
Leucine/analogs & derivatives/pharmacology
Leupeptins/pharmacology
Male
Parathyroid Hormone/*blood/metabolism
Protease Inhibitors/*pharmacology
Time Factors

Figure

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  Fig. 1. Time-dependent changes of the PTH levels in samples with different kinds of protease inhibitors. Data points are the mean ±SD (error bars) of PTH levels. Six groups of samples were stored at room temperature and the other group was stored at 4°C. Abbreviation: PTH, parathyroid hormone.

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