A VERTEBRATE MODEL OF EXTREME PHYSIOLOGICAL REGULATION

Investigation of vertebrate regulatory biology is restricted by the mo dest response amplitudes In mammalian model species that derive from a lifestyle of frequent small meals. By contrast, ambush-hunting snakes eat huge meals after long intervals. In juvenile pythons during feedi ng, there are large and rapid increases In metabolism and secretion, I n the activation of enzymes and transporter proteins, and in tissue gr owth. These responses enable an economic hypothesis concerning the evo lution of regulation to be tested. Combined with other experimental ad vantages, these features recommend juvenile pythons as the equivalent of a squid axon in vertebrate regulatory biology.