Inhibition of Spontaneous ACTH Release and Improved Response to CRF in Sheep Premedicated with the Enkephalin Analogue DAMME

Summary

The effect of IV injections of an enkephalin analogue (DAMME) in sheep prior to the administration of CRF has been compared with chlorpromazine-morphine (CPZ-M) injections as well as a chlorpromazine-morphine-nembutal (CPZ-M-N) regime. The results showed that the administration of DAMME 60 minutes prior to CRF injections, gave more consistent and more sustained inhibition of spontaneous plasma ACTH and plasma cortisol secretion than either CPZ-M or CPZ-M-N pre-treatment. Changes in plasma ACTH and plasma cortisol levels were more readily detectable in DAMME-treated sheep as compared with saline controls when 50 μg injections of CRF were given into the carotid artery. This suggests that DAMME may inhibit endogenous CRF release by an action at hypo-thalamic level or above.

Key-Words:

Enkephalin Analogue (DAMME) - CRF - Sheep ACTH