Pre-menstrual syndrome: a new concept in its pathogenesis and treatment

It is proposed that the normal regulation of the vasodilatation and vascular lengthening during the luteal phase of the menstrual cycle is due to the increased release of endothelial nitric oxide as a result of the maximum oestrogen/progesterone levels as manifest during this phase. Excessive levels of NO have additional systemic effects, and these may present as the pre-menstrual syndrome which classically occurs during the luteal phase of the menstrual cycle. The manufacture of NO is under the control of the enzyme NO synthase. The concentration of the latter can be affected by steroids. The proposed new treatment of PMS is premised on the basis that oral steroids given during the luteal phase will reduce the levels of NO and thus in turn will miminise the signs and symptoms of PMS.