Steroids include estrogen , cortisol , progesterone , and testosterone . Estrogen and progesterone are made primarily in the ovary and in the placenta during pregnancy, and testosterone in the testes . Testosterone is also converted into estrogen to regulate the supply of each, in the bodies of both females and males. Certain neurons and glia in the central nervous system (CNS) express the enzymes that are required for the local synthesis of pregnane neurosteroids , either de novo or from peripherally-derived sources. The rate-limiting step of steroid synthesis is the conversion of cholesterol to pregnenolone , which occurs inside the mitochondrion . [ 4 ]
Metabolic effects occurring during anabolic steroid therapy in immobilized patients or those with metastatic breast disease have included osteolytic-induced hypercalcemia. Anabolic steroids affect electrolyte balance, nitrogen retention, and urinary calcium excretion. Edema, with and without congestive heart failure, has occurred. Decreased glucose tolerance requiring adjustments in hyperglycemic control has been noted in diabetic patients. Significant increases in low density lipoproteins (LDL) and decreases in high density lipoproteins (HDL) have occurred. [ Ref ]
Unfortunately there exists no test that can determine a bodybuilder's detailed drug use in the far past, and doping test results are very easy to manipulate . Therefore, if you really want to know whether a bodybuilder is true natural, or which drugs he has been using to build his physique, you will have to ask him. The standard answer to this question is, however, always "No, I have never used any drugs". However, if you get to know the guy better, develop some friendship, give him some complements on his physique, and especially if he thinks that you are a drug user yourself or interested in becoming one, he might well loosen up and start telling you at least part of his true story.