Summary
Isolated rats livers were perfused with Krebs-Ringer-Bicarbonate (KRB) and different
doses of insulin or glucagon and with insulin plus glucagon. The isolated liver of
fasted rats and of rats treated with streptozotocin were perfused with (KRB). The
glomerulopressin activity of the ultrafiltrate of the liver perfusates were assayed
in the tonic tension contraction (TTC) of isolated stomach fundus from rats. As glomerulopressin
is known to be a glucuronide, it was inactivated with (β-glucuronidase to confirm
that the effect on the stomach fundus was due to the glomerulopressin and not to an
autacoid.
It was observed that glucagon increased the glomerulopressin activity of the perfusate
and that this activity was independent of the dose of glucagon used. Insulin produced
a decrease in the glomerulopressin activity of the perfusate, there being a log-dose
relationship between insulin and glomerulopressin.
There is a dose of insulin (1,5 × 10-5 U/min/kg) that potentiates the response to glucagon. Fasting and treatment with streptozotocin
induced an increase in the glomerulopressin activity of the perfusate.
These results suggest that glomerulopressin production is influenced by glucagon and
insulin, and that there is a specific ratio between these hormones that is very effective
in the production of glomerulopressin.
Key-Words:
Glomerulopressin
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Liver
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Insulin
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Glucagon
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Streptozotocin-Diabetes
