There are more than 90 different compounds that have been identified. Some of these compounds can be toxic to the body. Uremic toxins
Uremic toxins are any biologically active compounds that are retained due to kidney impairment. Many uremic salts can also be uremic toxins.Urea was one of the first metabolites identified. Its removal is directly related to patient survival but its effect on the body is not yet clear. Still, it is not certain that the symptoms currently associated with uremia are actually caused by excess urea, as one study showed that uremic symptoms were relieved by initiation of dialysis, even when urea was added to the dialysate to maintain the blood urea nitrogen level at approximately 90 mg per deciliter (that is, approximately 32 mmol per liter). Urea could be the precursor of more toxic molecules but it is more likely that damage done to the body is from a combination of different compounds which may act as enzyme inhibitors or derange membrane transport. Indoxyl sulfate is one of the better characterized uremic toxins. Indoxyl sulfate has been shown to aggravate vascular inflammation in atherosclerosis by modulating macrophage behavior. Biochemical characteristics
Many regulatory functions of the body are affected. Regulation of body fluids, salt retention, acid and nitrogenous metabolite excretion are all impaired and can fluctuate widely. Body fluid regulation is impaired due to a failure to excrete fluids, or due to fluid loss from vomiting or diarrhea. Regulation of salt is impaired when salt intake is low or the vascular volume is inadequate.
Likewise, other studies found that levels of estradiol and estrone are very similar after oral administration of roughly equimolar doses of estradiol (1.5 mg) and estradiol valerate (2 mg). A study of high-dose oral estradiol valerate found levels of estradiol of about 250 pg/mL after a single 10-mg dose in three women. Sublingual administration
Estradiol valerate has been studied by sublingual administration in premenopausal women for the purpose of cycle control and ovulation suppression in egg donation and surrogacy. It has been investigated for this indication, along with vaginal and transdermal estradiol, because oral estradiol valerate is sometimes unable to achieve adequate estradiol levels and hence proper cycle control in this situation. Sublingual administration of estradiol valerate bypasses the first pass that occurs with the oral route and results in higher levels of estradiol and improved cycle control. Sublingual estradiol valerate is also used in hormone therapy for transgender women.The administration of 2 mg oral micronized estradiol valerate tablets (Progynova, Schering) sublingually 3 or 4 times per day has been found to result in circulating estradiol levels of about 290 pg/mL to 460 pg/mL in premenopausal women (time of measurements not given). Steady-state levels of estradiol were achieved within about 2 or 3 days. Levels of progesterone, luteinizing hormone, and follicle-stimulating hormone were all considerably suppressed, and ovulation, as well as the associated mid-cycle hormonal surges, were prevented.