DIBUTYRYL-CYCLIC-AMP DOES NOT INFLUENCE GLOMERULAR COLLAGEN OR BASEMENT-MEMBRANE PRODUCTION INVITRO

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  • 1 January 1980
    • journal article
    • research article
    • Vol. 95  (2) , 282-288
Abstract
Glomeruli isolated from normal renal cortex were incubated for 3 h with radiolabeled proline in the presence or absence of dibutyryl cyclic[c]AMP. Following incubation, glomerular basement membranes were purified with osmotic lysis followed by selective solubilization of the cell membranes and intracellular proteins with detergents. This technique permitted quantitative recovery of radiolabeled membranes synthesized under different incubational conditions. Dibutyryl cAMP did not affect the incorporation of radioactive precursor glomerular basement membrane (control = 14.72 .+-. 1.08 cpm/.mu.g of membrane protein; cAMP = 14.43 .+-. 1.13). Nondialyzable [14C]protein and hydroxy[14C]proline were also measured in the media and in the various glomerular cell fractions obtained during isolation of the basement membranes. Protein ([14C]proline) and collagen (OH[14C]proline) secretion into the media in incubations with cAMP did not differ from that in control incubations. OH[14C]proline content was greatest (.simeq. 23%) in the water-soluble fraction recovered after osmotic lysis, but significant amounts of OH[14C]proline were also associated with the detergent-solubilized cell fractions. Dibutyryl cAMP had no effect on either glomerular protein or collagen synthesis in these experiments. Total glomerular basement membrane production in mixed cell populations is not modulated via cAMP-coordinated mechanism. cAMP may modulate the amount or kind of collagen synthesis by individual glomerular cell types.