Abstract: Certain embodiments of the invention provide a method (i.e., Enzyme Linked Oligonucleotide Sorbent Assay (ELOSA)) for the detection and/or quantification of a test oligonucleotide (e.g., a small oligonucleotide) in a test sample, such as a biological fluid, comprising: a) contacting the test sample with i) a capture reagent bound to a solid support, wherein the capture reagent comprises an oligonucleotide comprising a nucleic acid sequence complementary to the test oligonucleotide; and ii) a competition oligonucleotide operably linked to an enzyme, wherein the competition oligonucleotide comprises a nucleic acid sequence complementary to the capture oligonucleotide; thereby creating a reaction mixture; b) contacting the reaction mixture with a substrate that specifically binds to the enzyme, thereby generating an enzyme-substrate reaction product; and c) measuring the concentration of the enzyme-substrate reaction product, so as to detect and/or quantify the test oligonucleotide.

Abstract: Recombinant nucleotide sequences encoding mutated prolactin are described. Expression of the sequences result in mimics of a phosphorylated prolactin corresponding to a selected species. A particularly preferred mimic is mutated at serine 179 (corresponding to human PRL) where serine is substituted by an aspartate residue. This aspartate mutant is a very effective antagonist and shows no ability to stimulate Nb2 to cell proliferation.