No differential effects of porcine and human insulin on muscle sympathetic nerve activity during euglycaemia or hypoglycaemia.
On the basis of some clinical studies in diabetic patients, and experimental studies in normal humans, it has been suggested that hypoglycaemic autonomic responses are augmented with porcine (PI) compared to human insulin (HI). A difference in sensory processing has been reported following insulin-induced hypoglycaemia with PI compared to HI, and has been interpreted as different insulin effects on the central nervous system. In a double blind crossover comparison of HI and PI in nine healthy subjects, microneurographic recordings of muscle sympathetic nerve activity (MSNA) were performed, as well as measurements of cardiovascular and hormonal responses during a low dose hyperinsulinaemic euglycaemic glucose clamp (plasma insulin 60.1 +/- 1.9 mU ml-1 (mean +/- SEM)), followed by a period of insulin-induced hypoglycaemia. Plasma insulin and glucose were identical in the two sessions. Plasma glucose nadir during hypoglycaemia was 2.4 +/- 0.2 mmol l-1 for HI and 2.5 +/- 0.1 mmol l-1 for PI. During euglycaemia, MSNA increased from 24 +/- 2 to 34 +/- 3 and 23 +/- 2 to 30 +/- 2 burst/min (P:NS) for HI and PI, respectively, and during hypoglycaemia to 49 +/- 4 and 45 +/- 2 bursts min-1 (P:NS), respectively. The maximal hypoglycaemic increments of MSNA were not different (HI 15 +/- 4; PI 15 +/- 2 bursts min-1 (P:NS)) Responses of plasma noradrenaline and haemodynamic parameters did not differ either. This study does not indicate differing sympathetic responses to PI and HI in healthy humans. Evidence for a modulating effect of insulin on central sympathetic outflow was not found.
Frandsen
H A
HA
Department of Clinical Physiology, University of Copenhagen, Denmark.
Snitker
S
S
Christensen
N J
NJ
Madsbad
S
S
D000328:Adult; D000818:Animals; D005260:Female; D006801:Humans; D007003:Hypoglycemia / Q000503:physiopathology*; D007328:Insulin / Q000494:pharmacology*; D008297:Male; D009132:Muscles / Q000294:innervation*; D012016:Reference Values; D013552:Swine; D013564:Sympathetic Nervous System / Q000187:drug effects* / Q000503:physiopathology
D007328:Insulin