The Journal of Membrane Biology

, Volume 80, Issue 3, pp 243–248 | Cite as

Forskolin increases osmotic water permeability of rabbit cortical collecting tubule

  • Mark A. Dillingham
  • Jin K. Kim
  • Michael F. Horster
  • Robert J. Anderson


Forskolin is a unique diterpene that may directly activate the catalytic subunit of adenylate cyclase. We therefore examined the effect of 50 μm forskohn on osmotic water permeability in rabbit cortical collecting tubules perfusedin vitro. Forskolin increased net volume flux (J v , from 0.30 to 1.22 nl/mm/min,P<0.02) in all tubules. The hydro-osmotic effect of forskolin was similar with respect to magnitude and time course to that produced by a maximal dose (250 μU/ml) of arginine vasopressin. An additive effect onJ v andL p was not observed when maximal concentrations of forskolin and arginine vasopressin were given simultaneously. The compound d(CH2)5Tyr(Et) VAVP, which noncompetitively inhibits the vasopressin receptor, significantly reduced collecting tubular hydro-osmotic response to arginine vasopressin. In contrast, the hydro-osmotic response to forskolin was maintained in the presence of d(CH2)5 Tyr(Et)VAVP. However, the hydro-osmotic response to forskolin could be inhibited by 1.0 μm guanine 5′-(β,γ-imido) triphosphate (GppNHp) and by the calmodulin inhibitor N-(6-amenohexyl)-5-chloro-1-naphthalenesulfonamide (W-7). These results demonstrate that forskolin exerts an hydro-osmotic effect in the mammalian nephron which occurs independent of the vasopressin receptor. Guanine nucleotide regulatory proteins may modulate the osmotic water permeability effect of forskolin. Finally, calmodulin is required for full expression of the effect of forskolin to increase osmotic water flux.

Key Words

forskolin collecting tubule adenylate cyclase water permeability vasopressin 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. Arenare, B., Forrest, J.N. 1983. Forskolin stimulates maximal water flow and urea permeability and is synergistic with vasopressin in the toad urinary bladder.Clin. Res. 31:514AGoogle Scholar
  2. Awad, J.A., Johnson, R.A., Jakobs, K.H., Schultz, G. 1983. Interactions of forskolin and adenylate cyclase: Effects on substrate kinetics and protection against inactivation by heat and N-ethylmaleimide.J. Biol. Chem. 258:2960–2965Google Scholar
  3. Burg, M., Grantham, J., Abramow, M., Orloff, J. 1966. Preparation and study of fragments of single rabbit nephrons.Am. J. Physiol. 210:1293–1298Google Scholar
  4. Clark, R.B., Goka, T.J., Green, D.A., Barber, R., Butcher, R.W. 1982. Differences in the forskolin activation of adenylate cyclases in wid-type and variant lymphoma cells.Mol. Pharmacol. 22:609–613Google Scholar
  5. Cooper, D.M.F. 1983. Receptor-mediated stimulation and inhibition of adenylate cyclase.Curr. Top. Membr. Transp. 18:67–84Google Scholar
  6. Cuthbert, A.W., Spayne, J.A. 1982. Stimulation of sodium and of chloride transport in epithelia by forskolin.Br. J. Pharmacol. 76:033–035Google Scholar
  7. Downs, R.W., Jr., Aurbach, G.D. 1982. The effects of forskolin on adenylate cyclase in S49 wild type and cyc-cells.J. Cyclic Nucleotide Res. 8:235–242Google Scholar
  8. Fradkin, J.E., Cook, G.H., Kilhoffer, M.C., Wolff, J. 1982. Forskolin stimulation of thyroid adenylate cyclase and cyclic 3′5′-adenosine monophosphate accumulation.Endocrinology 111:849–856Google Scholar
  9. Hall, D.A., Grantham, J.J. 1980. Temperature effect on ADH response of isolated perfused rabbit collecting tubules.Am. J. Physiol. 239:F595–601Google Scholar
  10. Hildebrandt, J.D., Honoue, J., Birnbaumer, L. 1982. Guanine nucleotide inhibition of cyc-S49 mouse lymphoma cell membrane adenylate cyclase.J. Biol. Chem. 257:14723–14725Google Scholar
  11. Horster, M.F., Zink, H. 1982. Functional differentiation of the medullary collecting tubule: Influence of vasopessin.Kidney Int. 22:3609–3615Google Scholar
  12. Hudson, T.N., Fain, J.N. 1983. Forskolin-activated adenylate cyclase.J. Biol. Chem. 258:9755–9761Google Scholar
  13. Ishikawa, S., Kim, J.K., Schrier, R.W. 1983. Furtherin vivo evidence for antagonist to antidiuretic action of arginine vasopressin.Am. J. Physiol. (in press) Google Scholar
  14. Ishikawa, S., Schrier, R.W. 1982. Effect of arginine vasopressin antagonist on renal water excretion in glucocorticoid and mineralocorticoid deficient rats.Kidney Int. 22:587–593Google Scholar
  15. Jacobs, K.H., Schultz, G. 1983. Occurrence of a hormone-sensitive inhibitory coupling component of the adenylate cyclase in S49 lymphomas cyc-variants.Proc. Nat. Acad. Sci. USA 80:3899–3902Google Scholar
  16. Kim, J., Dillingham, M., Summers, S., Schrier, R.W. 1984. Effects of vasopressin antagonist on the cellular action of vasopressin in isolated tubules.Kidney Int. 25:304Google Scholar
  17. Levine, S.D., Kachadorian, W.A., Levin, D.N., Schlondorff, D. 1981. Effects of trifluoperazine on function and structure of toad urinary bladder.J. Clin. Invest. 67:662–672Google Scholar
  18. Litosch, I., Saito, Y., Fain, J.N. 1982. Forskolin as an activator of cyclic AMP accumulation and secretion in blowfly salivary glands.Biochem. J. 204:147–151Google Scholar
  19. Nishikawa, M., Hidaka, H. 1982. Role of calmodulin in platelet aggregation.J. Clin. Invest. 69:1348–1355Google Scholar
  20. Saito, Y., Wright, E.M. 1983. Bicarbonate transport across the frog choroid plexus and its control by cyclic nucleotides.J. Physiol. (London) 336:635–648Google Scholar
  21. Seamon, K.B., Daly, J.W. 1981a. Forskolin: A unique diterpene activator of cyclic AMP-generating systems.J. Cyclic Nucleotide Res. 7:201–224Google Scholar
  22. Seamon, K., Daly, J.W. 1981b. Activation of adenylate cyclase by the diterpene forskolin does not require the guanine nucleotide regulatory protein.J. Biol. Chem. 256:9799–9801Google Scholar
  23. Seamon, K.B., Daly, J.W. 1982. Guanosine 5′-(β,-Imido) triphosphate inhibition of forskolin-activated adenylate cyclase is mediated by the putative inhibitory guanine nucleotide regulatory protein.J. Biol. Chem. 257:11591–11596Google Scholar
  24. Seamon, K.B., Padgett, W., Daly, J.W. 1981. Forskolin: Unique diterpene activator of adenylate cyclase in membranes and intact cells.Proc. Natl. Acad. Sci. USA 78:3363–3367Google Scholar
  25. Siegl, A.M., Daly, J.W., Smith, J.B., 1982. Inhibition of aggregation and stimulation of cyclic AMP generation in intact human platelets by the diterpene forskolin.Mol. Pharmacol. 21:680–687Google Scholar
  26. Tanaka, T., Ohmura, T., Hidaka, H. 1982a. Hydrophobic interaction of the Ca2+ calmodulin complex with calmodulin antagonists.Mol. Pharmacol. 22:403–407Google Scholar
  27. Tanaka, T., Ohmura, T., Yamakado, T., Hidaka, H. 1982b. Two types of calcium-dependent protein phosphorylations modulated by calmodulin antagonists.Mol. Pharmacol. 22:408–412Google Scholar

Copyright information

© Springer-Verlag 1984

Authors and Affiliations

  • Mark A. Dillingham
    • 1
    • 2
  • Jin K. Kim
    • 1
    • 2
  • Michael F. Horster
    • 1
    • 2
  • Robert J. Anderson
    • 1
    • 2
  1. 1.Department of MedicineUniversity of Colorado Health Sciences CenterDenver
  2. 2.The Institute of PhysiologyUniversity of MunichMunichWest Germany

Personalised recommendations