Excretion hormones

After exerting their action in the organism, natural and synthetic hormones are catabolized in the liver by conjugation to glucuronide and/or sulfate moieties, forming more polar conjugated forms which are excreted via urine. This is the main route of hormone excretion in humans and pigs. A fraction of hormones is also excreted in a free form via feces in animals such as sheep and cattle this is the main route for hormone excretion (Table 3) [66, 67],... 

The main source of hormones is thus the excretions of the human population and livestock. The make-up and rate of hormone excretion by humans and animals varies as a function of their sex, age, state of reproduction and development, and for animals, their species (Table 3 [67, 79-83]). Human excretions are generally collected in sewers, while animal hormones are concentrated in manure thus, high levels of free and conjugated estrogens have been measured in raw sewage and manure [67, 79, 84-88]. Human hormones will eventually enter the environment mainly via wastewater treatment plants while hormones produced by animals reach the environment via direct excretion in fields or by manure spreading (treated or not) on the land. 

L5. Loraine, J. A., and Bell, E. T., Hormone excretion during the normal menstrual cycle. Lancet I, 1340-1342 (1963). 

F7. Frandsen, V. A., and Stakemann, G., The site of production of oestrogenic hormones in human pregnancy. Ill Further observations on the hormone excretion in pregnancy with anencephalic foetus. Acta Endocrinol. 47, 265-276 (1964). 

Hormone excretion/ Inducers of hepatic drug-metabohzing enzymes ... 

Korunka, C., Huemer, K. H., Litschauer, B., Karetta, B., and Kafka-Lutzow, A. (1996), Working with New Technologies—Hormone Excretion as Indicator for Sustained Arousal, Biological Psychology, Vol. 42, pp. 439-452. 

Nontraditional Hormones. Novel hormones identified ia cardiovascular tissue have profound effects on maintenance of blood pressure and blood volume ia mammals. Atrial natriuretic hormone (ANH) is a polypeptide hormone secreted from the atria of the heart. When the cardiac atrium is stretched by increased blood volume, secretion of ANH is stimulated ANH ia turn increases salt and water excretion and reduces blood pressure (6). Endothelin is a polypeptide hormone secreted by endothehal cells throughout the vasculature. Although endothelin is released into the circulation, it acts locally in a paracrine fashion to constrict adjacent vascular smooth muscle and increase blood pressure (7). 

Factors controlling calcium homeostasis are calcitonin, parathyroid hormone(PTH), and a vitamin D metabolite. Calcitonin, a polypeptide of 32 amino acid residues, mol wt - SGOO, is synthesized by the thyroid gland. Release is stimulated by small increases in blood Ca " concentration. The sites of action of calcitonin are the bones and kidneys. Calcitonin increases bone calcification, thereby inhibiting resorption. In the kidney, it inhibits Ca " reabsorption and increases Ca " excretion in urine. Calcitonin operates via a cyclic adenosine monophosphate (cAMP) mechanism. 

The level of circulating hormones is lowered indirecdy by -butyl 3,5-diiodo-4-hydroxyben2oate which displaces them from their carriers (TBG and TBPA) and thus accelerates their metaboHsm and excretion (6). 

Drugs with endocrinological functions or side-effects are common, but oestrogenic hormones in oral contraceptives are particularly widely used. Pharmaceuticals and their metabolites eventually find their way into the environment, predominantly via excretion into sewage. ... 

There are undifferentiated stem cells of the blood elements in the bone marrow that differentiate and mature into erythrocytes, (red blood cells), thrombocytes (platelets), and white blood cells (leukocytes and lymphocytes). The production of erythrocytes is regulated by a hormone, erythropoietin (see the section on kidney toxicity), that is synthetized and excreted by the kidney. An increase in the number of premature erythrocytes is an indication of stimulation of erythropoiesis, i.e., increased production of erythrocytes in anemia due to continuous bleeding. 

Mammals, fungi, and higher plants produce a family of proteolytic enzymes known as aspartic proteases. These enzymes are active at acidic (or sometimes neutral) pH, and each possesses two aspartic acid residues at the active site. Aspartic proteases carry out a variety of functions (Table 16.3), including digestion pepsin and ehymosin), lysosomal protein degradation eathepsin D and E), and regulation of blood pressure renin is an aspartic protease involved in the production of an otensin, a hormone that stimulates smooth muscle contraction and reduces excretion of salts and fluid). The aspartic proteases display a variety of substrate specificities, but normally they are most active in the cleavage of peptide bonds between two hydrophobic amino acid residues. The preferred substrates of pepsin, for example, contain aromatic residues on both sides of the peptide bond to be cleaved. 

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