Summary
In situ hybridization is a morphologic method of localizing specific DNA or RNA sequences
at the individual cell level. The technique can be applied to frozen or fixed tissues
and cytologic preparations; various types of probes can be utilized and the reaction
can be visualized by autoradiography using isotopic markers or by colorimetric methods.
In the field of endocrinology, in situ hybridization has seen numerous applications;
the detection of viral infections, the characterization of tumors with markers of
endocrine differentiation, the determination of hormone synthesis by normal cells
and neoplasms. Ectopic hormone production and the production of other substances such
as growth factors and cytokines have been established using this new methodology and
it has been used to examine production of specific receptors by individual cells in
many endocrine tissues. The data that have emerged allow structure-function correlations
that have not previously been possible using molecular techniques that are applied
to homogenized tissues or even using the most sophisticated morphologic methods such
as immunohistochemistry and electron microscopy.
Key words
In situ hybridization - RNA - DNA - hormone synthesis
