Blood-to-Brain Glucose Transport, Cerebral Glucose Metabolism, and Cerebral Blood Flow Are Not Increased After Hypoglycemia
Article Figures & Tables
Figures
- FIG. 1.
Mean ± SE plasma values for insulin (A) and glucose (B) concentrations before and during hyperinsulinemic stepped hypoglycemic clamps before (day 1, ▪) and after (day 2, □) ∼24 h of hypoglycemia (55 mg/dl, 3.0 mmol/l) in nine subjects who underwent PET studies after hypoglycemia.
- FIG. 2.
Mean ± SE values for plasma epinephrine (A) and norepinephrine (B) concentrations before and during hyperinsulinemic stepped hypoglycemic clamps before (day 1, ▪) and after (day 2, □) ∼24 h of hypoglycemia (55 mg/dl, 3.0 mmol/l) in nine subjects who underwent PET studies after hypoglycemia.
- FIG. 3.
Mean ± SE values for neurogenic (A) and neuroglycopenic (B) symptom scores before and during hyperinsulinemic stepped hypoglycemic clamps before (day 1, ▪) and after (day 2, □) ∼24 h of hypoglycemia (55 mg/dl, 3.0 mmol/l) in nine subjects who underwent PET studies after hypoglycemia.
- FIG. 4.
Mean ± SE values for plasma glucagon and pancreatic polypeptide concentrations before and during hyperinsulinemic stepped hypoglycemic clamps before (day 1, ▪) and after (day 2, □) ∼24 h of hypoglycemia (55 mg/dl, 3.0 mmol/l) in nine subjects who underwent PET studies after hypoglycemia.
- FIG. 5.
Mean ± SE rates of blood-to-brain glucose transport (A), cerebral glucose metabolism (B), and cerebral blood flow (C) determined with PET during hyperinsulinemic mildly hypoglycemic clamps (65 mg/dl, 3.6 mmol/l) in eight subjects studied after euglycemia (After EU) and nine subjects studied after ∼24 h of hypoglycemia (55 mg/dl, 3.0 mmol/l) (After HYPO).
Tables
- TABLE 1
Plasma growth hormone, cortisol, serum nonesterified fatty acids, blood β-hydroxybutyrate, lactate, and alanine concentrations before and during hyperinsulinemic stepped hypoglycemic clamps before (Day 1) and after (Day 2) approximately 24 h of hypoglycemia (55 mg/dl, 3.0 mmol/l) in nine subjects who underwent PET studies after hypoglycemia
Nominal glucose (mg/dl) ∼90 85 75 65 55 P Growth hormone (ng/ml)* Day 1 1.3 ± 0.7 1.5 ± 1.0 2.1 ± 1.5 7.7 ± 2.1 18.2 ± 2.4 0.001 Day 2 1.1 ± 0.4 3.5 ± 2.4 5.1 ± 2.4 2.6 ± 1.3 8.4 ± 2.8 Cortisol (μg/dl)† Day 1 11.5 ± 1.6 10.3 ± 1.7 8.9 ± 1.1 12.5 ± 1.6 17.1 ± 1.8 0.087 Day 2 13.4 ± 1.8 9.8 ± 1.7 12.4 ± 3.1 9.8 ± 2.0 17.4 ± 3.6 Nonesterified fatty acids (μmol/l) Day 1 381 ± 76 104 ± 26 79 ± 14 79 ± 20 66 ± 22 0.592 Day 2 307 ± 84 74 ± 8 54 ± 7 48 ± 10 45 ± 10 β-Hydroxybutyrate (μmol/l) Day 1 145 ± 37 64 ± 24 106 ± 38 66 ± 24 66 ± 17 0.927 Day 2 111 ± 22 86 ± 22 64 ± 18 84 ± 28 68 ± 19 Lactate (μmol/l) Day 1 1045 ± 129 1451 ± 163 1349 ± 95 1308 ± 81 1824 ± 231 0.001 Day 2 963 ± 115 1024 ± 68 839 ± 90 753 ± 69 1063 ± 94 Alanine (μmol/l) Day 1 469 ± 54 407 ± 26 420 ± 421 377 ± 46 403 ± 33 0.342 Day 2 291 ± 34 311 ± 26 310 ± 31 257 ± 27 259 ± 26 Data are means ± SE.
- *
* To convert growth hormone to pmol/l, multiply by 44.15;
- †
† to convert cortisol to nmol/l, multiply by 27.59.
- TABLE 2
Neuroendocrine parameters during the PET studies in eight subjects studied after euglycemia and nine subjects studied after approximately 24 h of hypoglycemia*
After EU After HYPO P Glucose (mg/dl) 64 ± 0 66 ± 1 — Epinephrine (pg/ml) 302 ± 77 112 ± 34 0.032 Norepinephrine (pg/ml) 253 ± 29 208 ± 31 0.310 Glucagon (pg/ml) 118 ± 29 43 ± 8 0.012 Pancreatic polypeptide (pg/ml) 117 ± 35 38 ± 9 0.035 Growth hormone (ng/ml) 12.1 ± 4.8 10.6 ± 4.1 0.809 Cortisol (μg/dl) 14.2 ± 2.4 11.7 ± 2.1 0.430 Data are means ± SE.
- *
* To convert glucose to mmol/l multiply by 0.0551, epinephrine to pmol/l multiply by 5.485, norepinephrine to nmol/l multiply by 0.005911, glucagon to pmol/l multiply by 0.2871, pancreatic polypeptide to pmol/l multiply by 0.239, growth hormone to pmol/l multiply by 44.15, and cortisol to nmol/l multiply by 27.59. EU, euglycemia; HYPO, hypoglycemia.
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