Ontogeny of erythrocyte insulin binding in the sheep

Michael S. Kappy, Leslie P. Plotnick, J. Ross Milley, Adam Rosenberg, Richard A. Molteni, M. Douglas Jones, Michael A. Simmons

Research output: Contribution to journalArticlepeer-review

6 Scopus citations


The ontogeny of insulin binding in the sheep was studied using the erythrocytes (RBCs) of 31 fetuses, 10 lambs, and 5 adult animals. Six fetuses were studied on three occasions over a 2-week period from 120-135 days of gestation to provide longitudinal data on changes in insulin binding. Maximal percent binding of [125I]iodoinsulin and receptor concentration decreased significantly as the age of the animal increased (r = -0.76, P < 0.001 and r = -0.49, P <0 0.001, respectively). Total loss of insulin binding to RBCs was estimated to occur in the second postnatal month, and the RBCs from the adult sheep showed no specific insulin binding. The osmotic fragility of RBCs in each developmental group of animals was also studied to assess possible differences in RBC membrane properties. RBC osmotic fragility was significantly lower in fetuses than in adult sheep (osmotic fragility50 = 0.55% phosphate-buffered saline vs. 0.76% phosphate-buffered saline, respectively; P < 0.001). The data suggest that fetal RBCs of lower osmotic fragility and high insulin binding capacity are progressively replaced during late prenatal and early postnatal life by adult-type RBCs of increased osmotic fragility and lacking binding capacity for insulin. The timing of the disappearance of insulin binding to RBCs coincides with the final transition in the animals from a monogastric to a ruminant metabolic state, and may reflect a change in the need for insulin with age.

Original languageEnglish (US)
Pages (from-to)611-617
Number of pages7
Issue number2
StatePublished - Aug 1981

ASJC Scopus subject areas

  • Endocrinology


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