Serum Levels of Neurosteroid Allopregnanolone in Patients with Premenstrual Syndrome and Patients after Thyroidectomy.

OBJECTIVE: To evaluate whether altered levels of progesterone and its main neuroactive metabolite allopregnanolone do occur in premenopausal women. The second part of this study deals with allopregnanolone levels in thyreoidectomized women. METHODS: Allopregnanolone, a neurosteroid acting by its allosteric interaction with GABAA receptors and progesterone, were determined in two groups of patients which have in common certain psychic disorders generally characterized by the depression and anxiety, namely in 23 women with premenstrual syndrome (PMS) and in 52 women after total thyreoidectomy. The control groups consisted of women of the same age without premenstrual complaints and with normal thyroid function, respectively. RESULTS: Significantly lower values of allopregnanolone in PMS patients than in controls have been found in the follicular phase, indicating the lower peripheral activity of 5alpha-reductase of C21-steroids detectable at low progesterone levels only. In the thyroidectomized patients significantly higher values of allopregnanolone have been found in the luteal phase. CONCLUSION: The increase of allopregnanolone level in thyroidectomized patients may represent one of the counterregulatory mechanisms protecting the organism from some consequences of hormonal disbalance after thyroid ablation.