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TITLE:
Brain metabolism of progesterone, coping
behaviour and emotional reactivity in male rats from two psychogenetically selected lines.
AUTHOR:
Steimer T; Driscoll P; Schulz PE
AUTHOR AFFILIATION:
Clinical Psychopharmacology Unit, University
Institute of Psychiatry (IUPG), Geneva, Switzerland.
SOURCE:
J Neuroendocrinol 1997 Mar;9(3):169-75
NLM CIT. ID:
97244691
ABSTRACT:
Brain metabolites of progesterone such as
tetrahydroprogesterone (THP) act on GABAA receptors and have anxiolytic properties. The
formation of THP and its 5 alpha-reduced precursor, dihydroprogesterone (DHP) was measured
in vitro in various microdissected brain areas obtained from males of two
psychogenetically selected rat lines, i.e. the Roman High-(RHA/Verh) and low-(RLA/Verh)
Avoidance rats, which are known to differ in emotional reactivity and/or anxiety. The
behavioural and neuroendocrine responses of these rats were also measured following
exposure to a novel environment in two different test situations. The formation of DHP and
THP was found to be significantly higher in the frontal cortex (FCX), and DHP in the bed
nucleus of the stria terminalis (BST), of the hypoemotional RHA/Verh rats. In addition,
enzymatic activity in the FCX was found to be inversely correlated with behavioural
measures of anxiety. These results suggest that individual, possibly
genetically-determined differences in brain production of endogenous anxiolytics derived
from progesterone may account at least in part for the behavioural differences
characterizing these two lines, and provide further evidence that neurosteroids acting on
the GABAergic system may play an important role in modulating physiological and/or
behavioural responses to environmental stressors.
When my office
lease expired at the end of 2004, I decided to turn it into a
"sabbatical" from my private practice. Many years ago, in my
grandfather's 89th year of life, he told me, "John, it is important
to smell the roses while you can still smell them." His life
gave living a very good reputation. It is also true that the
pursuit of that philosophy required my grandfather to to re-open his
assay office/ore market in Wickenburg, Arizona as a 75-year-old because
he had run a little short of retirement money. Thus, if blessed with his
luck and health, I'll be back.. --jjh
