Steroid isolation , depending on context, is the isolation of chemical matter required for chemical structure elucidation, derivitzation or degradation chemistry, biological testing, and other research needs (generally milligrams to grams, but often more  or the isolation of "analytical quantities" of the substance of interest (where the focus is on identifying and quantifying the substance (for example, in biological tissue or fluid). The amount isolated depends on the analytical method, but is generally less than one microgram.  [ page needed ] The methods of isolation to achieve the two scales of product are distinct, but include extraction , precipitation, adsorption , chromatography , and crystallization . In both cases, the isolated substance is purified to chemical homogeneity; combined separation and analytical methods, such as LC-MS , are chosen to be "orthogonal"—achieving their separations based on distinct modes of interaction between substance and isolating matrix—to detect a single species in the pure sample. Structure determination refers to the methods to determine the chemical structure of an isolated pure steroid, using an evolving array of chemical and physical methods which have included NMR and small-molecule crystallography .  :10–19 Methods of analysis overlap both of the above areas, emphasizing analytical methods to determining if a steroid is present in a mixture and determining its quantity. 
Developmental and Reproductive toxicity : Propyl and butyl parabens appear to reduce sperm production  ,  and lead to reduced testosterone levels,  while methyl- and ethyl-parabens do not affect sperm production. These effects appear to be dose-dependent.  In addition, one study found that maternal exposure to butylparaben during gestation and lactation alters the development of the reproductive organs and sperm production.  In general, propyl- and butylparabens, specifically, appear disrupt male reproductive system and affect the reproductive organs.  ,  This is consistent with their estrogenic activity noted above.
When activated macrophages start to secrete IL-1, which synergistically with CRH increases ACTH,  T-cells also secrete glucosteroid response modifying factor (GRMF), as well as IL-1; both increase the amount of cortisol required to inhibit almost all the immune cells.  Immune cells then assume their own regulation, but at a higher cortisol setpoint. The increase in cortisol in diarrheic calves is minimal over healthy calves, however, and falls over time.  The cells do not lose all their fight-or-flight override because of interleukin-1's synergism with CRH. Cortisol even has a negative feedback effect on interleukin-1  —especially useful to treat diseases that force the hypothalamus to secrete too much CRH, such as those caused by endotoxic bacteria. The suppressor immune cells are not affected by GRMF,  so the immune cells' effective setpoint may be even higher than the setpoint for physiological processes. GRMF affects primarily the liver (rather than the kidneys) for some physiological processes.