Summary
Glucagon secretion by isolated pancreatic rat islets was not affected by an increase
of the glucose concentration from 2.5 to 5.0 mM, but was stimulated by 25 mM arginine.
This stimulation was only slightly increased by pregnancy and lactation. Insulin secretion
increased, when the glucose concentration was raised from 2.5 to 5.0 mM, especially
in pregnant islets and was also stimulated by arginine. The arginine stimulated insulin
release was greatly augmented during late pregnancy and lactation. Islet content did
not reflect the changes in secretion: glucagon content increased in the course of
pregnancy and lactation, while insulin content was increased during late pregnancy,
but not during lactation. It is concluded that, unlike insulin, glucagon is only marginally
involved in the increase in anabolism during pregnancy and lactation.
Key words
Insulin - Glucagon - Islet of Langerhans - Gestation - Lactation - Arginine
