Adenylate cyclase activity of renal cortical carcinoma and its relation to histology and ultrastructure
Hunt, N.H.; Shortland, J.R.; Michelangeli, V.P.; Hammonds, J.C.; Atkins, D.; Martin, T.J.
Cancer Research 38(1): 23-31
1978
ISSN/ISBN: 0008-5472 PMID: 618579 Document Number: 131314
Tissue morphology and adenylate cyclase activity were studied in 23 patients with renal cortical carcinoma. EM and examination of glycogen distribution demonstrated that tumors were composed of cells with predominantly proximal tubular cell characteristics or cells with distal tubular cell characteristics. Light microscopy was not suitable for this classification. Basal (unstimulated) adenylate cyclase activity in membranes prepared from control uninvolved renal cortex was 155 .+-. 25 (mean .+-. SE; n, 19) pmol cyclicAMP/mg protein per 15 min. In tumors with proximal characteristics, the basal adenylate cyclase activity was 754 .+-. 120 (n, 14) and, in those with distal characteristics, 247 .+-. 32 (n, 4) pmol cAMP/mg protein per 15 min. Adenylate cyclase activity in control tissue was stimulated by parathyroid hormone, prostaglandins, E1 and E2, glucagon and NaF. Tumor adenylate cyclase responded poorly and infrequently to parathyroid hormone, responded subnormally to prostaglandins E1 and E2 and NaF, and did not respond to glucagon. Basal adenylate cyclase activity and the hormone responsiveness of the enzyme were modified in the established tumor. High rates of cAMP production may occur in malignant cells, an observation that was made, to the present time, with several in vivo tumors. This differs from much published in vitro evidence that associates malignant transformation with low adenylate cyclase activity and cellular cAMP levels.