Logo of jcinvestThe Journal of Clinical InvestigationCurrent IssueArchiveSubscriptionAbout the Journal
J Clin Invest. 1975 Jun; 55(6): 1278–1283.
PMCID: PMC301883

Proinsulin, insulin, and C-peptide concentrations in human portal and peripheral blood.

Abstract

Concentrations of insulin, proinsulin, and C-peptide were measured in portal and peripheral venous blood in six nondiabetic, nonobese subjects. Portal vein samples were obtained by umbilical vein catheterization. Three subjects were studied with intravenous infusion of 25 g glucose, and three with 30 g arginine. Insulin and proinsulin were determined in the insulin immunoassay after separation by gel filtration, and C-peptide was measured by direct immunoassay. With both glucose and arginine stimulation, portal vein levels of all three peptides peaked at 90-120 s after the onset of the stimulus. Relative increases in insulin concentration were greater than those of proinsulin or C-peptide. In peripheral venous blood, maximal levels of the three peptides were observed later (2-5 min), and the increase in insulin relative toproinsulin and C-peptide was not as great. At the time of peak secretion, portal vein insulin and C-peptide approached equimolar concentrations, and proinsulin, as measured against an insulin standard, comprised approximately 2.5% of the total immunoreactive insulin. After stimulation by glucose or arginine, portal insulin, proinsulin and C-peptide levels were not correlated with the concentrations measured in simultaneously drawn peripheral samples. At all sampling times, however, significant correlation was found between insulin and C-peptide in both peripheral and portal blood. The results indicate that under the conditions studied, insulin and C-peptide are secreted in equimolar concentrations in man, and that proinsulin is secreted in the same proportion to insulin as found in the pancreas. Consideration of the relative secretory and metabolic rates of the three beta cell peptides explains their peripheral concentrations. The data further support the use of plasma C-peptide as an indicator of beta cell secretory function.

Full text

Full text is available as a scanned copy of the original print version. Get a printable copy (PDF file) of the complete article (966K), or click on a page image below to browse page by page. Links to PubMed are also available for Selected References.

Selected References

These references are in PubMed. This may not be the complete list of references from this article.
  • Rubenstein AH, Block MB, Starr J, Melani F, Steiner DF. Proinsulin and C-peptide in blood. Diabetes. 1972;21(2 Suppl):661–672. [PubMed]
  • Kitabchi AE. Clinical significance of proinsulin in human plasma. South Med J. 1972 Jul;65(7):833–838. [PubMed]
  • Katz AI, Rubenstein AH. Metabolism of proinsulin, insulin, and C-peptide in the rat. J Clin Invest. 1973 May;52(5):1113–1121. [PMC free article] [PubMed]
  • Rubenstein AH, Pottenger LA, Mako M, Getz GS, Steiner DF. The metabolism of proinsulin and insulin by the liver. J Clin Invest. 1972 Apr;51(4):912–921. [PMC free article] [PubMed]
  • Block MB, Mako ME, Steiner DF, Rubenstein AH. Circulating C-peptide immunoreactivity. Studies in normals and diabetic patients. Diabetes. 1972 Oct;21(10):1013–1026. [PubMed]
  • Melani F, Rubenstein AH, Steiner DF. Human serum proinsulin. J Clin Invest. 1970 Mar;49(3):497–507. [PMC free article] [PubMed]
  • Blackard WG, Nelson NC. Portal and peripheral vein immunoreactive insulin concentrations before and after glucose infusion. Diabetes. 1970 May;19(5):302–306. [PubMed]
  • Melani F, Rubenstein AH, Oyer PE, Steiner DF. Identification of proinsulin and C-peptide in human serum by a specific immunoassay. Proc Natl Acad Sci U S A. 1970 Sep;67(1):148–155. [PMC free article] [PubMed]
  • SAIFER A, GERSTENFELD S. The photometric microdetermination of blood glucose with glucose oxidase. J Lab Clin Med. 1958 Mar;51(3):448–460. [PubMed]
  • SAMOLS E, RYDER JA. Studies on tissue uptake of insulin in man using a differential immunoassay for endogenous and exogenous insulin. J Clin Invest. 1961 Nov;40:2092–2102. [PMC free article] [PubMed]
  • Kanazawa Y, Kuzuya T, Ide T, Kosaka K. Plasma insulin responses to glucose in femoral, hepatic, and pancreatic veins in dogs. Am J Physiol. 1966 Aug;211(2):442–448. [PubMed]
  • Erwald R, Hed R, Nygren A, Röjdmark S, Sundblad L, Wiechel KL. Immunoreactive insulin in the portal and the peripheral venous blood after intravenous tolbutamide administration. Diabetes. 1971 Oct;20(10):686–690. [PubMed]
  • Erwald R, Hed R, Nygren A, Röjdmark S, Sundblad L, Wiechel KL. Insulin concentration in portal and peripheral venous blood after oral glucose in human pancreatitis. Acta Med Scand. 1973 Jul-Aug;1-2(1):103–109. [PubMed]
  • Berger W, Göschke H, Moppert J, Künzli H. Insulin concentrations in portal venous and peripheral venous blood in man following administration of glucose, galactose, xylitol and tobutamide. Horm Metab Res. 1973 Jan;5(1):4–8. [PubMed]
  • Schein PS. Islet cell tumors: current concepts and management. Ann Intern Med. 1973 Aug;79(2):239–257. [PubMed]
  • Waddell WR, Sussman KE. Plasma insulin after diversion of portal and pancreatic venous blood to vena cava. J Appl Physiol. 1967 Apr;22(4):808–812. [PubMed]
  • Kaden M, Harding P, Field JB. Effect of intraduodenal glucose administration on hepatic extraction of insulin in the anesthetized dog. J Clin Invest. 1973 Aug;52(8):2016–2028. [PMC free article] [PubMed]
  • SAMOLS E, RYDER JA. Studies on tissue uptake of insulin in man using a differential immunoassay for endogenous and exogenous insulin. J Clin Invest. 1961 Nov;40:2092–2102. [PMC free article] [PubMed]
  • Rastogi GK, Letarte J, Fraser TR. Proinsulin content of pancreas in human fetuses of healthy mothers. Lancet. 1970 Jan 3;1(7636):7–9. [PubMed]
  • Chance RE, Ellis RM. Proinsulin. Single-chain precursor of insulin. Arch Intern Med. 1969 Mar;123(3):229–236. [PubMed]
  • Sando H, Borg J, Steiner DF. Studies on the secretion of newly synthesized proinsulin and insulin from isolated rat islets of Langerhans. J Clin Invest. 1972 Jun;51(6):1476–1485. [PMC free article] [PubMed]
  • Rastogi GK, Sinha MK, Dash RJ. Insulin and proinsulin content of pancreases from diabetic and nondiabetic subjects. Diabetes. 1973 Nov;22(11):804–807. [PubMed]
  • Burr IM, Balant L, Stauffacher W, Renold AE, Grodsky G. Dynamic aspects of proinsulin release from perifused rat pancreas. Lancet. 1969 Oct 25;2(7626):882–883. [PubMed]
  • Gutman RA, Fink G, Shapiro JR, Selawry H, Recant L. Proinsulin and insulin release with a human insulinoma and adjacent nonadenomatous pancreas. J Clin Endocrinol Metab. 1973 May;36(5):978–987. [PubMed]
  • Lockwood DH, Misbin RI. Proinsulin content of adult and fetal pancreatic tissue extracted after rapid freezing in situ. Horm Metab Res. 1972 Jul;4(4):232–234. [PubMed]
  • Goldsmith SJ, Yalow RS, Berson SA. Significance of human plasma insulin Sephadex fractions. Diabetes. 1969 Dec;18(12):834–839. [PubMed]
  • Gutman RA, Lazarus NR, Penhos JC, Fajans S, Recant L. Circulating proinsulin-like material in patients with functioning insulinomas. N Engl J Med. 1971 May 6;284(18):1003–1008. [PubMed]
  • Sherman BM, Pek S, Fajans SS, Floyd JC, Jr, Conn JW. Plasma proinsulin in patients with functioning pancreatic islet cell tumors. J Clin Endocrinol Metab. 1972 Aug;35(2):271–280. [PubMed]
  • Gorden P, Sherman B, Roth J. Proinsulin-like component of circulating insulin in the basal state and in patients and hamsters with islet cell tumors. J Clin Invest. 1971 Oct;50(10):2113–2122. [PMC free article] [PubMed]
  • Starr JI, Rubenstein AH. Metabolism of endogenous proinsulin and insulin in man. J Clin Endocrinol Metab. 1974 Feb;38(2):305–308. [PubMed]

Articles from The Journal of Clinical Investigation are provided here courtesy of American Society for Clinical Investigation

Formats:

Save items

Related citations in PubMed

See reviews...See all...

Cited by other articles in PMC

See all...

Links

  • Compound
    Compound
    PubChem chemical compound records that cite the current articles. These references are taken from those provided on submitted PubChem chemical substance records. Multiple substance records may contribute to the PubChem compound record.
  • MedGen
    MedGen
    Related information in MedGen
  • PubMed
    PubMed
    PubMed citations for these articles
  • Substance
    Substance
    PubChem chemical substance records that cite the current articles. These references are taken from those provided on submitted PubChem chemical substance records.

Recent Activity

Your browsing activity is empty.

Activity recording is turned off.

Turn recording back on

See more...