Twenty-Four-Hour Resting Prolactin Levels in Male Rats: The Effect of Septal Lesions and Order of Sacrifice

Diurnal variation in resting prolactin levels was studied in male rats that were normal, sham-operated, or lesioned in the septal nuclei. Separate groups of rats were sampled by decapitation every 3 or 4 hours in two separate studies during a 24 h period consisting of 12 h light and 12 h dark. Male rats did not exhibit a significant diurnal variation in resting prolactin levels. A septal lesion had no effect on resting prolactin levels. …