Abstract
Indices of carbohydrate and lipid metabolism were inves tigated in male New Zealand
genetically hypertensive and normotensive rats. Cross-breeding of male rats of these
strains with female Brattleboro diabetes insipidus rats also provided the opportunity
to examine the metabolic impact of vasopres sin and its deficiency in hypertensive
and normotensive rats. Hypertensive and normotensive rats, with or without diabetes
insipidus, were fasted for 24h, exsanguinated and their blood/plasma analysed for
various indices of carbohydrate and lipid metabolism. Whilst each group of rats maintained
fasted normoglycemia, hypertensive rats, with or without vasopressin deficiency, were
hypoinsulinaemic relative to normotensive counterparts. Moreover, hypertensive or
normotensive vasopressin-deficient rats were hypoinsulinaemic relative to vasopressin-replete
counterparts. In vasopressin-replete rats, the apparently improved insulin sensitivity
in hypertension was associated with significant falls in plasma glucagon, triglycerides
and total cholesterol. Finally, normotensive vasopressin-deficient rats were hypoglucagonaemic
relative to the vasopressin replete group. These data demonstrate that independent
of vasopressin status, hypertension in the New Zealand strain and the diabetes insipidus
hybrid was associated with improved insulin sensitivity. However, endogenous vasopressin
exercises an influential role in carbohydrate and lipid metabolism in normotensive
rats.
Key words
Rat - Vasopressin - Insulin - Metabolism - Hypertension
