Localization of Hormones by Autoradiography and Other Histochemical Techniques

Informuation al)ollt the localization of hormones, that is, their cellular amid subcellular sites of niamiufacture, storage, transport or action, is still fragmemitary. Progress in techmiiques within the last decade has l)rovided valuable information and promise for future research. In the elucidation of the subcellular distributiomi of homniones, biochemnical approaches, utilizing centrifugal fractiomiatiomi with radioactively labeled comnpoumids of high specific activity (28), are ahead of pictorial techmiiques. rrhus uptake kiiietics amid cellular protein-binding factors could be studied for estradiol (9, 29, 48), aldosterone (22) and testosterone (2). The histochemist is challenged to confirm amid supplement the biochemical data by a different techmiical approach. Most im1)ortamit, however, is the potemitial of the morphologist to provide information about individual cells within the topographic context. The histologic or histochemnical investigatiomi, leaving the tissue structures relatively intact, may produce results which cannot be obtained otherwise, especially in tissues with pronoumiced heterogeneous cell types such as ovary, pituitary amid braimi. Therefore, histochemical informiiatiomi provides an indispemisable link between physiology amid morphology. In the localization of hormomies two miiajor problems exist, mianiely (a) to obtain authemitic amid meaningful results with regard to hormone distribution in situ, and (b) to interpret the demonstrated pattern of localizatiomi. Hormmiones, in general, are not boumid chemically withimi the tissues, but held omily by weak adsorptive forces. It is therefore a rerequisite to prevent or comitrol diffusion whenever the tissue is subjected to nomiphysiologic conditions dumimig homnogenizatiomi, imicubation, histologic “fixation,” dehydration, clearing, embedding, wet moumiting amid the like. Information degradation durimig tissue preparatiomi has led umiwary investigators to publish