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Support for oxygen demand as a proximal stimulant of postprandial cardiac hypertrophy in carnivorous reptiles
Author(s) -
Slay Christopher E,
Hicks James W
Publication year - 2011
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.25.1_supplement.lb530
Subject(s) - postprandial , medicine , specific dynamic action , endocrinology , cardiology , muscle hypertrophy , biology , meal , diabetes mellitus
In carnivorous reptiles, particularly those animals which utilize intermittent (“sit‐and‐wait”) feeding strategies, the processes associated with digestion result in a large increase in aerobic demand. This increased metabolic demand, referred to as specific dynamic action (SDA), is notable for the large scope and duration of elevated oxygen consumption. Previous work (Secor and Diamond, 1995; Andersen et al, 2005) has demonstrated a 40% increase in ventricular mass of Burmese pythons ( Python molurus ) during the first 48 hours of the postprandial period. We hypothesize that insufficient oxygen supply during this period of elevated oxygen demand may serve as the proximal cue for postprandial cardiac hypertrophy. We have exposed both American alligators ( Alligator mississippiensis ) and Burmese pythons to 12% O 2 during the postprandial period and have observed, in each case, an increase in ventricular mass above levels found in fasted animals and animals digesting in normoxic environments. Ultrasonography seems to indicate an increase in ventricular dilation in those animals with postprandial cardiac hypertrophy, supporting earlier evidence that cardiac hypertrophy serves to increase stroke volume and increase oxygen delivery capacity. We hope to demonstrate functional consequences of these postprandial cardiac hypertrophies in future studies. CES would like to acknowledge support from the NSF GK‐12 Fellowship (DGE‐0638751 to UCI) and an NSF Graduate Research Fellowship. Additional funding was provided by NSF grant IOS 0922756 to JWH.