When only mg of progesterone was applied topically, the plasma level rose 39 percent, whereas saliva level rose 5-fold. This indicates that only a small portion of the added progesterone entered the plasma, whereas the saliva clearly showed a hefty increase of bioavailable progesterone. When an 88-fold larger dose was applied topically, the plasma level rose only -fold while the simultaneous saliva level rose 57-fold. This indicates that only the saliva reflected the great increase in absorbed bioavailable progesterone. The progesterone found in the saliva obviously was blood-borne, but it should be clear that the portion of the blood carrying the progesterone was not the plasma (serum) but, rather, was via red blood cells.
There are 20 different R groups, and so 20 different amino acids. Since each R group is slightly different, each amino acid has different properties, and this in turn means that proteins can have a wide range of properties. The following table shows the 20 different R groups, grouped by property, which gives an idea of the range of properties. You do not need to learn these, but it is interesting to see the different structures, and you should be familiar with the amino acid names. You may already have heard of some, such as the food additive monosodium glutamate, which is simply the sodium salt of the amino acid glutamate. Be careful not to confuse the names of amino acids with those of bases in DNA, such as cysteine (amino acid) and cytosine (base), threonine (amino acid) and thymine (base). There are 3-letter and 1-letter abbreviations for each amino acid.
Alcohols are among the most common organic compounds . They are used as sweeteners and in making perfumes, are valuable intermediates in the synthesis of other compounds, and are among the most abundantly produced organic chemicals in industry. Perhaps the two best-known alcohols are ethanol and methanol (or methyl alcohol). Ethanol is used in toiletries, pharmaceuticals, and fuels, and it is used to sterilize hospital instruments. It is, moreover, the alcohol in alcoholic beverages . The anesthetic ether is also made from ethanol. Methanol is used as a solvent , as a raw material for the manufacture of formaldehyde and special resins , in special fuels, in antifreeze , and for cleaning metals.