QUANTITATIVE HISTOLOGIC DISTRIBUTION OF ADENOSINE-3',5'-MONOPHOSPHATE IN THE RAT ADRENAL AND EFFECT OF ADRENOCORTICOTROPIN

Adaptations of both the enzymatic radioisotope displacement and the luminescence methods for measurement of adenosine-3',5'-monophosphate in picomole amounts in sub-milligram samples (e.g., fresh-frozen microtome sections of tissue or 10 µl homogenate) were made and applied to establishing the quantitative histologic distribution of adenosine-3',5'-monophosphate in the adrenals of untreated and adrenocorticotropic hormone-treated rats. A sharp peak in concentration of 24 pmoles/mg wet weight (1.3 pmoles/µg protein-nitrogen) was observed in the reticular zone of the untreated rats and the values fell off rapidly in the medulla to a minimum of less than one-third the peak value, and in the fasciculata and glomerulosa to less than one-half. The adrenocorticotropic hormone injections caused a second peak to appear in the outer fasciculata with a height comparable to that in the reticularis, but the concentrations in all zones were elevated. These two peaks were about 30 pmoles/mg wet weight (2 pmoles/µg protein-nitrogen), and the concentrations also fell to a minimum in the medulla, about one-third the peak values, and to relatively low values in inner fasciculata and glomerulosa, almost one-half the peak value.