A rapid method for analyzing serum pro-insulin-like growth factor-II in patients with non-islet cell tumor hypoglycemia.

Abstract

CONTEXT:

Non-islet cell tumor hypoglycemia (NICTH) results from the hypersecretion of pro-IGF-II by a large, usually mesenchymal tumor. Detection of pro-IGF-II in serum is a potential tumor marker in these patients.

OBJECTIVE:

The aim of this study was to validate a rapid and reliable method for determining serum pro-IGF-II.

PATIENTS:

Serum samples from 16 patients with NICTH were studied.

MAIN OUTCOME MEASURE:

The main outcome measure was serum concentration of pro-IGF-II determined by immunoblot analysis of pro-IGF-II and mature IGF-II after 16.5% tricine-SDS-PAGE, which was compared with pro-IGF-II measured by standard RIA after size-exclusion acid chromatography.

RESULTS:

The analyses of patients' sera by size-exclusion acid chromatography showed that 68 +/- 19% of IGF-II were present in the pro-IGF-II form, whereas only 18 +/- 4% corresponded to pro-IGF-II in controls. Scanning densitometry of immunoblots showed 67 +/- 16% in the bands corresponding to pro-IGF-II in patients' sera, compared with 27 +/- 9% in controls. The detection sensitivity of tricine-SDS-PAGE method was the same as for size-exclusion chromatography, but the tricine-SDS-PAGE method is quicker and requires smaller amounts of serum.

CONCLUSION:

Tricine-SDS-PAGE followed by IGF-II immunoblot analysis provides a rapid, reproducible, and sensitive method for the separation of serum pro-IGF-II from mature IGF-II and is a useful laboratory evaluation of patients with a clinical diagnosis of NICTH.

• Authors: Farideh Miraki-Moud, Ashley B Grossman, Michael Besser, John P Monson, Cecilia Camacho-Hübner
• Journal: The Journal of clinical endocrinology and metabolism (J Clin Endocrinol Metab) Vol. 90 Issue 7 Pg. 3819-23 (Jul 2005) ISSN: 0021-972X [Print] United States
• PMID: 15840753 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Protein Precursors
• proinsulin-like growth factor II
• Insulin-Like Growth Factor I
• Insulin-Like Growth Factor II

Topics

• Adult
• Aged
• Aged, 80 and over
• Blotting, Western
• Chromatography, Gel
• Female
• Humans
• Hypoglycemia (blood)
• Insulin-Like Growth Factor I (analysis)
• Insulin-Like Growth Factor II (analysis)
• Male
• Middle Aged
• Neoplasms (blood)
• Protein Precursors (blood)