Amiloride and Other Blockers of Electrolyte Flux As Inhibitors of Progesterone‐Stimulated Meiotic Maturation In Xenopus Oocytes

ABSTRACT Amiloride and seven of its analogues, as well as seven substances of other structural types, all of which control electrolyte transport, were tested for their effectiveness for inhibiting the progesterone‐stimulated meiotic maturation cycle of oocytes from the amphibian Xenopus luevis. Data were also collected on the ability of the oocytes to recover from the drug's inhibitory effect and on the toxicity of each drug. the data revealed that up to a 14‐fold difference exists in the inhibitory concentration 50% between substances, that recovery from the drug's inhibitory effect ranged from non‐reversible to almost complete reversibility and that toxicity, as measured by failure to exclude trypan blue, ranged from 0 to 57%. In some, but not all cases, the failure to recover from the drug's inhibitory effects could be correlated to the drug's toxic effects. Amiloride which has been shown to be a reversible inhibitor of cell proliferation in rapidly dividing mammalian cell populations has similar properties on the oocyte maturation division cycle of Xenopus.