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Suppression of Insulin Secretion by Falling Plasma Glucose Levels is Impaired in Type 2 Diabetes
Author(s) -
Hosker J. P.,
Burnett M. A.,
Matthews D. R.,
Turner R. C.
Publication year - 1988
Publication title -
diabetic medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.474
H-Index - 145
eISSN - 1464-5491
pISSN - 0742-3071
DOI - 10.1111/j.1464-5491.1988.tb01124.x
Subject(s) - medicine , endocrinology , insulin , diabetes mellitus , islet , clamp , plasma glucose , type 2 diabetes , glucose clamp technique , pancreatic hormone , insulin resistance , mechanical engineering , clamping , engineering
The ability of Type 2 diabetic patients to suppress islet B‐cell secretion in response to falling plasma glucose levels has been studied with two different protocols. (1) Five diet‐treated diabetic patients and 6 normal subjects were studied after the termination of a hyperglycaemic clamp at 15 mmol l −1 for 150 min, with the plasma glucose levels then being allowed to fall and the glucose clamp re‐established at 10 mmol l −1 . The plasma insulin levels fell in normal subjects from 178 ± 141 (± SD) mU l −1 at the end of the 15 mmol l −1 clamp to 147 ± 97 mU l −1 ( p < 0.02) 20 min later, whereas in diabetic patients there was no significant change from 61 ± 41 to 56 ± 35 mU l −1 , respectively (NS). (2) The second study was performed to assess the turn‐off of islet B‐cell secretion with diabetic patients and normal subjects starting at comparable plasma insulin levels. Twelve diet‐treated diabetic patients and 11 normal subjects were given a continuous low‐dose glucose infusion for 60 min at a rate of 5 mg kg l −1 ideal body weight min l −1 , after which the infusion was turned off and the plasma glucose level allowed to fall. The plasma insulin levels in normal subjects fell from 18.8 ± 8.2 mU l −1 at the end of the infusion to 13 ± 4.3 mU l −1 ( p < 0.01) and 10.5 ± 3 mU l −1 ( p <0.005) 20 and 30 min later, respectively, whereas in diabetic patients there was no change from 18.4 ± 6.8 mU l −1 at the end of the infusion to 18.3 ± 5.6 (NS) and 17.1 ± 5.1 mU l −1 (NS) 20 and 30 min later. Diet‐treated Type 2 diabetic patients have reduced islet B‐cell sensitivity to falling plasma glucose levels, compared with normal subjects.