A pilot study on alterations of brain chromosomal protein phosphorylation by steroids during ageing.

The modulatory effects of the steroid hormones estradiol-17 beta and hydrocortisone on phosphorylation of chromosomal proteins of the cerebral hemispheres (CH) of young and old rats was studied in vitro. The results indicate that the extent of phosphorylation decreases in both histone and non-histone-chromosomal (NHC) protein fractions as the age proceeds. Besides, both the hormones stimulate phosphorylation in young as well as old rats. However the pattern of stimulation shown by estradiol differs from that by hydrocortisone. In addition the extent of stimulation by these hormones is significantly reduced in old rats. Modulation of phosphorylation as provoked by these two hormones seems to play an important role in differential gene expression during ageing.