Increased urea synthesis and/or suppressed ammonia production in the African lungfish, Protopterus annectens, during aestivation in air or mud.

The objective of this study was to elucidate how the African lungfish, Protopterus annectens, ameliorated ammonia toxicity during 12 or 46 days of aestivation in air or in mud. Twelve days of aestivation in air led to significant increases in contents of urea, but not ammonia, in tissues of P. annectens.