Androstan is

an organic compound, a representative of st eroids. A basic skeleton of carbon particles present in the andro gen (male sex hormones). Androstan is built with 19 carbon atoms. Like all steroids is coupled to a system of four rings - three s ześcioczłonowych and one pięcioczłonowego. Rings can be located differently relative to each other. The next ring is called the successive letters of the alphabet. And so the rings created by the carbon atoms numbered from 1 to 10 are referred to as A and B.