We didn’t even suspected these peptides and counter regulators of peptides were there until carcinoid patients came along and taught us what they really do – by making too much of these. That’s why these tumors are so sophisticated, so enigmatic, because there are probably 3 or 4 more hormones that we don’t even know about in our bodies ...
Peptides (from Gr.: πεπτός, peptós "digested"; derived from πέσσειν, péssein "to digest") are short chains of amino acid monomers linked by peptide bonds. The covalent chemical bonds are formed when the carboxyl group of one amino acid reacts with the amino group of another.
• Know the structure, properties and functions of eicosanoids • Know the pathways of eicosanoid metabolism and clinical implications • Clinical Implications of eicosanoids • Steroid hormone biosynthesis • Mechanism of action of steroid hormones General properties of eicosanoids--Small molecules, from polyunsaturated fatty acids. 20 Cs.
Proteins and peptides are fundamental components of cells that carry out important biological functions. Proteins give cells their shape, for example, and they respond to signals transmitted from the extracellular environment. Certain types of peptides play key roles in regulating the activities of other molecules.
Peptides, however, may be subdivided into oligopeptides, which have few amino acids (e.g., 2 to 20), and polypeptides, which have many amino acids. Proteins are formed from one or more polypeptides joined together. Hence, proteins essentially are very large peptides.
A major difference between peptide and steroid hormones is the fact that peptide hormones will bind to receptors on the cells they are effecting, and induce a cascading effect. Steroid hormones on the other hand, will travel to the nucleus and have major effects.