The principal reproductive androgen of males, largely responsible for sexual maturation, some libido, and a range of metabolic reactions that, while supplying short-term strengths, creates a long-term fragility and brittleness if not in balance with less garish but more sustainable metabolic buffers. It is secreted by the Leydig cells of the testes, as well as smaller amounts in the adrenal cortices of both sexes. It is made under the direction of LH from the pituitary, and, if oversecreted, can be inhibited by sperm-producing cells, diminished pituitary support, and a rise in blood levels of its waste-product, stored in adipose tissues...estradiol