Pre-menstrual steroids

A number of steroid hormones and their metabolites fluctuate in the circula tion across the human menstrual cycle. In addition to their classic actions on the hypothalamo-pituitary-gonadal axis, many of these hormones act as ' neuroactive steroids' to alter the function of neurotransmitters, such as G ABA, within central nervous system circuits. Clinically, these steroids are important because they have not only acute but also long-term effects, and 'withdrawal' properties. This review discusses the effects of steroids suc h as 3 alpha -OH-5 alpha -pregnan-20-one (3 alpha ,5 alpha -THP or allopreg nanolone) which alter GABA function in distinct ways dependent upon the tim e course of exposure, to either enhance or decrease inhibition in the brain . These effects are discussed in light of recent clinical findings which se ek to further characterize the steroid milieu which underlies pre-menstrual dysphoria.