title: Attenuated glucose recovery from hypoglycemia in the elderly.
abstract: Advanced age is a risk factor for hypoglycemia caused by sulfonylureas (and insulin) used to treat diabetes mellitus. Therefore, we hypothesized that there is an age-associated impairment of glucose counterregulation and further that this is the result of a sedentary life-style. To test these hypotheses, glycemic and neuroendocrine responses to hypoglycemia, produced by 0.05 U/kg body wt insulin i.v. were measured in nondiabetic elderly subjects (age 65.1 +/- 0.9 yr n = 23)--and in a subset (n = 11) again after 1 yr of physical training (which increased VO2 max by 5.2 +/- 0.9 ml.kg-1.min-1, P less than 0.05)--and compared with these responses in nondiabetic young subjects (23.8 +/- 0.6 yr, n = 18). Recovery from hypoglycemia was attenuated (analysis of variance P less than 0.001) in the elderly (plasma glucose recovery rate 29.4 +/- 2.2 vs. 42.7 +/- 5.0 microM/min, P less than 0.02). This attenuation was the result of a smaller counterregulatory increment in glucose production (maximum increment 13.3 +/- 1.1 vs. 17.2 +/- 1.1 mumol.kg-1.min-1; P less than 0.05) rather than a greater increment in glucose utilization in the elderly. The attenuated glucose recovery was associated with higher plasma insulin concentrations (maximum increment 1385 +/- 122 vs. 940 +/- 72 pM, P less than 0.01) and reduced glucagon responses to hypoglycemia (maximum increment 43 +/- 6 vs. 66 +/- 12 ng/L). The epinephrine, norepinephrine, cortisol, and growth hormone responses were similar, although the epinephrine response was slightly delayed and the growth hormone response appeared smaller in the elderly.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Department of Medicine, Washington University School of Medicine, St. Louis, Missouri 63110.
authors.forename: J C
authors.initials: JC
authors.lastname: Marker
authors.forename: P E
authors.initials: PE
authors.lastname: Cryer
authors.forename: W E
authors.initials: WE
authors.lastname: Clutter
mesh_terms: D020155:3-Hydroxybutyric Acid; D000328:Adult; D000367:Age Factors; D000368:Aged; D000409:Alanine / Q000097:blood; D000704:Analysis of Variance; D001786:Blood Glucose / Q000378:metabolism*; D001794:Blood Pressure; D002096:C-Peptide / Q000097:blood; D004837:Epinephrine / Q000097:blood; D005230:Fatty Acids, Nonesterified / Q000097:blood; D005934:Glucagon / Q000097:blood; D013006:Growth Hormone / Q000097:blood; D006339:Heart Rate; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D006885:Hydroxybutyrates / Q000097:blood; D007003:Hypoglycemia / Q000097:blood / Q000503:physiopathology*; D007328:Insulin / Q000097:blood / Q000494:pharmacology*; D007773:Lactates / Q000097:blood; D008875:Middle Aged; D009638:Norepinephrine / Q000097:blood
chemical_list: D001786:Blood Glucose; D002096:C-Peptide; D005230:Fatty Acids, Nonesterified; D006885:Hydroxybutyrates; D007328:Insulin; D007773:Lactates; D013006:Growth Hormone; D005934:Glucagon; D000409:Alanine; D020155:3-Hydroxybutyric Acid; D006854:Hydrocortisone; D009638:Norepinephrine; D004837:Epinephrine