Winder W W, MacLean P S, Chandler S L, Huang W, Mills R H
Zoology Department, Brigham Young University, Provo, Utah 84602.
J Appl Physiol (1985). 1994 Jul;77(1):270-6. doi: 10.1152/jappl.1994.77.1.270.
Responses to insulin-induced hypoglycemia in fasted sham-operated (SHAM), adrenodemedullated (ADM), and epinephrine-infused ADM (ADM + E) rats were studied to ascertain the specific role of epinephrine in increasing resting skeletal muscle content of adenosine 3',5'-cyclic monophosphate (cAMP) and fructose 2,6-bisphosphate (F-2,6-P2), which are involved in stimulation of muscle glycogenolysis and lactate production. Rats from each group were fasted for 24 h and then infused intravenously with insulin (30, 60, or 90 min) to produce plasma insulin values of approximately 92 microU/ml. One-half of the insulin-infused ADM rats were also infused with epinephrine (ADM + E). Muscle and blood lactate, muscle cAMP, and muscle F-2,6-P2 increased and muscle glycogen decreased in SHAM rats. Each of these changes was prevented or attenuated in ADM rats and restored in ADM + E rats. Liver cAMP, glycogen, and F-2,6-P2 responses to hypoglycemia were similar in SHAM, ADM, and ADM + E rats. Blood glucose decreased to 0.74 +/- 0.05 mM in ADM rats compared with 1.54 +/- 0.11 mM in SHAM and 1.34 +/- 0.15 mM in ADM + E rats after 90 min of insulin infusion. The increase in plasma epinephrine is therefore essential in the counterregulatory response to insulin-induced hypoglycemia in fasted rats. Resting skeletal muscle glycogenolysis and lactate production for hepatic gluconeogenic substrate appear to be important components of the counterregulatory response in fasted rats.
研究了空腹假手术（SHAM）、肾上腺髓质切除（ADM）和肾上腺素输注的ADM（ADM + E）大鼠对胰岛素诱导的低血糖的反应，以确定肾上腺素在增加静息骨骼肌中3',5'-环磷酸腺苷（cAMP）和果糖2,6-二磷酸（F-2,6-P2）含量方面的具体作用，这些物质参与刺激肌肉糖原分解和乳酸生成。每组大鼠禁食24小时，然后静脉输注胰岛素（30、60或90分钟），以使血浆胰岛素值达到约92微单位/毫升。一半接受胰岛素输注的ADM大鼠还输注了肾上腺素（ADM + E）。SHAM大鼠的肌肉和血液乳酸、肌肉cAMP和肌肉F-2,6-P2增加，肌肉糖原减少。ADM大鼠中这些变化均被阻止或减弱，而在ADM + E大鼠中恢复。SHAM、ADM和ADM + E大鼠肝脏cAMP、糖原和F-2,6-P2对低血糖的反应相似。胰岛素输注90分钟后，ADM大鼠的血糖降至0.74±0.05毫摩尔/升，而SHAM大鼠为1.54±0.11毫摩尔/升，ADM + E大鼠为1.34±0.15毫摩尔/升。因此，血浆肾上腺素的增加对于空腹大鼠对胰岛素诱导的低血糖的对抗调节反应至关重要。静息骨骼肌糖原分解和为肝脏糖异生底物生成乳酸似乎是空腹大鼠对抗调节反应的重要组成部分。
