Diurnal Variation of Plasma Concentrations of Cortisol, Aldosterone and Electrolytes in the Ram

Summary

The peripheral plasma concentrations of cortisol, aldosterone and electrolytes were measured simultaneously in 2 groups of 20 + 8 rams sampled respectively every 3 hours in June 1974 and hourly in June 1975 over a 24-hr period, in the Algiers area. In spite of large individual variations, the mean plasma concentrations of cortisol and aldosterone exhibited synchronous diurnal changes: they were highest in the morning, decreased during the afternoon until 18.00 h, and remained lowest during the first part of the night.

Changes in plasma concentrations of electrolytes were slight and not correlated with hormonal variations.

Key-Words:

Cortisol - Aldosterone - Nycthemeral Rhythms - Ram