title: Improved beta cell function, with reduction in secretion of intact and 32/33 split proinsulin, after dietary intervention in subjects with type 2 diabetes mellitus.
abstract: Diet in Type 2 diabetes often reduces both hyperglycaemia and weight and both these factors may contribute to improvement in beta cell function. Sixty-nine subjects with newly diagnosed Type 2 diabetes had their glucose, insulin, intact and 32/33 split proinsulin measured at diagnosis, and after 16 (12-20) weeks of conventional diet. In the whole group following diet there was reduction in weight (p < 0.0001), Haemoglobin A1 (p < 0.0001), and fasting glucose (p < 0.0001). There was a fall in fasting intact proinsulin (p < 0.03), 32/33 split proinsulin (p < 0.0001), and the percentage of fasting proinsulin to total insulin-like molecules (p < 0.0001). Subjects were separated according to weight loss (group 1 < 0.5 kg, group 2 0.5-4 kg, group 3 > 4 kg). Only subjects in group 3 (mean weight loss 6.2 kg) had a fall in fasting insulin (p < 0.04). The fasting glucose achieved following diet was positively correlated with the initial fasting glucose (r = 0.7) and negatively correlated with the degree of insulin deficiency at diagnosis (with the initial 30 min insulin r = -0.62). The effect of diet on the final concentration of insulin, 32/33 split proinsulin and intact proinsulin was examined using multiple regression. The final insulin concentration was determined by the initial BMI and absolute weight loss, 32/33 split proinsulin concentration by the initial fasting glucose and absolute glucose fall, and intact proinsulin concentration by a combination of both weight loss and glucose reduction.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Ipswich Diabetes Centre, Ipswich Hospital, London, UK.
authors.forename: M J
authors.initials: MJ
authors.lastname: Davies
authors.forename: J
authors.initials: J
authors.lastname: Metcalfe
authors.forename: J L
authors.initials: JL
authors.lastname: Day
authors.forename: A
authors.initials: A
authors.lastname: Grenfell
authors.forename: C N
authors.initials: CN
authors.lastname: Hales
authors.forename: I P
authors.initials: IP
authors.lastname: Gray
mesh_terms: D001786:Blood Glucose / Q000378:metabolism; D015992:Body Mass Index; D003920:Diabetes Mellitus / Q000097:blood / Q000178:diet therapy / Q000503:physiopathology*; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000178:diet therapy / Q000503:physiopathology*; D003927:Diet, Diabetic; D005215:Fasting; D005260:Female; D006801:Humans; D007328:Insulin / Q000097:blood; D007515:Islets of Langerhans / Q000378:metabolism / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D009765:Obesity; D011384:Proinsulin / Q000097:blood / Q000378:metabolism*; D011498:Protein Precursors / Q000097:blood / Q000378:metabolism*; D013997:Time Factors
chemical_list: D001786:Blood Glucose; D007328:Insulin; D011498:Protein Precursors; C070703:proinsulin, des(31,32)-; D011384:Proinsulin