CARBONIC-ANHYDRASES IN THE HUMAN ADRENAL-GLAND AND ITS DISORDERS - IMMUNOHISTOCHEMICAL AND BIOCHEMICAL-STUDIES OF THE ENZYMES

To study the possible roles of carbonic anhydrases (CA) in the human a drenal glands, an immunohistochemical study (using polycloncal antibod ies against CA I and II), and a biochemical assay of CA activity (base d on the change in pH caused by the hydration of CO2) were performed i n normal human adrenal tissue and adrenocortical adenomas. All of 10 n ormal adrenal glands showed positive staining for CA II in the zona gl omerulosa, whereas weak CA I-positive staining was detected in only 5 glands. A biochemical study of 3 normal human adrenal specimens also d emonstrated CA activity only in the outer adrenal cortex. Of 26 adreno cortical adenoma specimens (15 aldosteronomas, 6 nonfunctioning adenom as, and 5 Cushing's adenomas), CA I and II immunoreactivity was observ ed in only 3 and 5 aldosteronoma samples, respectively. A biochemical analysis of CA in 5 adenoma specimens (3 aldosteronomas, 2 nonfunction ing adenomas) detected enzymatic activity in 2 aldosteronomas. In all 26 specimens of non-neoplastic attached adrenals of adrenocortical ade nomas, CA II immunoreactivity was present in the zona glomerulosa cell s. These results indicate that CAs are present in the zona glomerulosa cells of the non-neoplastic human adrenals glands (but not in the maj ority of adrenocortical adenomas) and that CA II may constitute the ma jor form of the enzyme. Exclusive localization of CA II in the zona gl omerulosa cells in human adrenal glands may suggest a possible involve ment of CAs in aldosterone biosynthesis or secretion through ion trans port, or both. Our data also suggest that CA II can be used as an immu nochemical marker for the zona glomerulosa cells in human adrenal glan ds.