A soluble PC-1 circulates in human plasma: Relationship with insulin resistance and associated abnormalities

Lucia Frittitta, Stefania Camastra, Roberto Baratta, Benedetta V. Costanzo, Monica D'Adamo, Salvatore Graci, Daniela Spampinato, Betty A. Maddux, Riccardo Vigneri, Eleuterio Ferrannini, Vincenzo Trischitta

Research output: Contribution to journalArticlepeer-review

Abstract

An increased tissue content of PC-1, an inhibitor of insulin receptor signaling, may play a role in insulin resistance. Large scale prospective studies to test this hypothesis are difficult to carry out because of the need for tissue biopsies. The aim of this study was to investigate whether PC-1 is measurable in human plasma and whether its concentration is related to insulin sensitivity. A soluble PC-1, with mol wt and enzymatic activity similar to those of tissue PC-1, was measurable in human plasma by a specific enzyme-linked immunosorbent assay and was inversely correlated to skeletal muscle PC-1 content (r = -0.5; P <0.01). The plasma PC-1 concentration was decreased (P <0.05) in insulin-resistant (22.7 ± 3.0 ng/mL; n = 25) compared to insulin-sensitive (36.7 ± 4.5; n = 25) nondiabetic subjects and was correlated negatively with the waist/hip ratio (r = -0.48; P <0.001) and mean blood pressure (r = -0.3; P <0.05) and positively with high density lipoprotein/total cholesterol (r = 0.38; P <0.01) and both the M value and the plasma free fatty acid level decrement at clamp studies (r = 0.28; n = 50; P = 0.05 and r = 0.43; n = 22; P <0.05, respectively). A plasma PC-1 concentration of 19 ng/mL or less identified a cluster of insulin resistance-related alterations with 75% accuracy. In conclusion, PC-1 circulates in human plasma, and its concentration is related to insulin sensitivity. This may help to plan studies aimed at understanding the role of PC-1 in insulin resistance.

Original languageEnglish
Pages (from-to)3620-3625
Number of pages6
JournalJournal of Clinical Endocrinology and Metabolism
Volume84
Issue number10
Publication statusPublished - 1999

ASJC Scopus subject areas

  • Biochemistry
  • Endocrinology, Diabetes and Metabolism

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