Cell Hormones

The serum requirement of many transformed animal cells is also reduced. The reduction in the serum requirement can, in many cases, be explained by a loss of some of the cells hormone, growth factor or adhesion requirements. The altered hormone, growth factor, or attachment requirements can be studied by growing the cells in serum-free medium. 

In 1979, Ross et al 22i" measured the ODMR of tyrosine in glucagon and the derivative [12-homoarginine]glucagon to examine the effect of chemical modification of a lysine residue adjacent to Tyr-10 and Tyr-13. The guanidinated analogue had lower potency than glucagon in a fat cell hormone receptor assay. Since the tyrosine ODMR and other spectral properties of the polypeptide, including circular dichroism, were essentially identical, it was... 

The fats also have a plastic function as they are included in cell membranes and other cell structures. The central and peripheral nervous systems are rich in lipids. PNFA are included in cell membranes, with their most significant function being the synthesis of cell hormones — prostaglandins. The properties of cell membranes as well as their interaction with external factors depend on the relation of PNFA concentration in cell components. In humans, prostaglandins are created not only in tissues but also in thrombocytes (thromboxanes) and in leucocytes (leukotrienes). The biological action of thrombocytes is extremely variant and depends on PNFA type which are the basis for fatty acid creation. 

Steroid or thyroid hormone enters the cell hormone-receptor complex acts in the nucleus. 

When lipids are required by the body for energy, adipose cell hormone-sensitive lipase (activated by epinephrine, and inhibited by insulin) initiates degradation of stored triacyl glycerol. 

A large number of glucocorticoid-resistant subclones of the lymphoid cell lines S49.1, WEHI-7 and CEM-7 have been isolated in the way described above. Receptor defects of different types were found to be the prevailing cause for resistance. For classifying the receptor abnormalities a whole-cell hormone-binding assay followed by crude cell fractionation has been employed [20,57],... 

Insulin also exerts a stimulatory effect on the synthesis of cholesterol in the liver. In this tissue, HMG-CoA reductase is activated. HMG-CoA reductase, like hormone-sensitive lipase, can exist in two forms one is phosphorylated (inactive) and the other is dephosphorylated (active). Phosphorylation of the enzyme depends on an increase in the cellular concentration of cAMP and activation of protein kinase. The dephosphorylation (activation) is catalyzed by a phosphatase. In fat cells, a similar phosphatase dephosphorylates (inactivates) hormone-sensitive lipase. Insulin stimulates the activity of the phosphatase in both liver and fat cells. In this way, active HMG-CoA reductase predominates in the liver cell and directs HMG-CoA into cholesterol synthesis, and in the fat cell hormone-sensitive lipase is inactivated. 

Both plants and animals use mixed function oxidases (simultaneously oxidize two substrates) Acyl-CoA desaturases localized on the ER. Similar mixed function oxidases are also used to modify structural components of cells, hormones etc. so we will use the acyl-CoA desaturase as an example for this group of enzymes. In the acyl-CoA desaturase reaction molecular oxygen is used to oxidize both a fatty acid and NADH, each providing two of the the four electrons needed by the oxygen ... 

A one-cell thick sheet of epithelial cells covers the surfaces of the villi and lines of crypts. Some of the cell types identified in the epithelial lining of the small intestine are enterocytes (digestion and absorption), goblet cells (mucus secretion), endocrine cells (hormone secretion), and M cells (absorption of food and antigens). 

Epinephrine Adrenal medulla (chromaffin cells) Hormonal Cardiac muscle, smooth muscle, and widespread effects on cellular metabolism... 

GI (enterochromaffin cells) Hormonal (paracrine) Gastrointestinal smooth muscle... 

Paracrine regulation of islet cell hormonal secretion. , Stimulation ... 

Sensory Receptor Sensory Neuron Neuroendocrine Cell Hormone Effector Effects... 

FIGURE 73-2. Thyroid hormone synthesis. Iodide is transported from the plasma, through the cell, to the apical membrane where it is organified and coupled to the thyroglobulin (TG) synthesized within the thyroid cell. Hormone stored as colloid re-enters the cell through endocytosis and moves back toward the basal membrane, where T4 is secreted. 

Finland follitropin alfa protein Gonal-F Recombinant human FSH in its alpha glycoform expressed in CHO cells Hormone... 

Fejes-Toth G, Naray-Fejes-Toth A. Isolated principal and intercalated cell hormone responsiveness and Na-K-ATPase activity. 

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