Insulin receptors in cystic fibrosis: increased receptor number and altered affinity
Lippe, B.M.; Kaplan, S.A.; Neufeld, N.D.; Smith, A.; Scott, M.
Pediatrics 65(5): 1018-1022
1980
ISSN/ISBN: 0031-4005 PMID: 6988790 Document Number: 164859
Patients with cystic fibrosis have pancreatic disorganization with associated pancreatic exocrine insufficiency. Endocrine hormonal secretion is also affected but diminution in insulin secretion is rarely accompanied by overt diabetes. In 7 patients with cystic fibrosis studied to determine their carbohydrate tolerance and the status of peripheral monocyte insulin receptors, oral glucose tolerance tests showed the presence of mild hyperglycaemia and diminished insulin secretion. Mean insulin receptor sites per cell were increased above controls, 25 000 against 13 100 sites per cell, while receptor affinity was diminished. The increase in receptor number could be a consequence of the insulinopenia or the decreased bodyweight of the patients or both and act as a compensatory mechanism maintaining a degree of relative insulin sensitivity. Ultimate carbohydrate tolerance may be a function of the patient's ability to maintain increased receptor numbers in the face of hypoinsulinaemia and impaired receptor affinity.