Summary
Factor VIII (FVIII) and plasminogen activator activity (PAA) rise during hypoglycaemia,
and this might contribute to the vascular complications of diabetes. Similar changes
in haemostasis accompany raised plasma levels of vasopressin (aVP) and adrenaline.
To investigate the effects of these hormones on haemostasis during hypoglycaemia and
the role of plasma insulin concentrations, eight insulin-dependent diabetic patients
underwent controlled hypoglycaemia for 20 min and 13 diabetic patients were investigated
during hyperinsulinaemia with blood glucose maintained at 8.0 mmol/1. During hypoglycaemia,
insulin levels increased to median values of 114 mU/1, aVP rose from 0.5 to 4.4 (p
<0.005) pg/ml and adrenaline from 0.4 to 4.4 nmol/l (p <0.005). FVIII coagulant activity
(FVIII :C) rose from 0.75 to 1.09 iU/ml (p <0.01) and the ristocetin co-factor (FVIIIR:Co)
and von Willebrand factor antigen (vWF:Ag) showed similar responses. PAA increased
from 156 to 745 units (p <0.005). During hyperinsulinaemia, insulin rose following
infusion from 24 to 52 and 118 mU/l, maintained for an hour at each level. Despite
this, plasma aVP, FVIII :C, FVIIIR:Co, vWF:Ag and PAA remained unchanged. This study
indicates that the marked changes in FVIII, vWF and PAA concentrations which accompany
hypoglycaemia depend on low blood glucose and not raised plasma insulin. The response
in probably mediated by increases in adrenaline and aVP, which are part of the physiological
response to hypoglycaemia.
Keywords
Hypoglycaemia - Insulin - Vasopressin - Adrenaline - Factor VIII - Plasminogen activator
- Insulin-dependent diabetes
