Abstract
The dose response to exogenous glucagon (10−9 to 5 X 10−7M) and Cyclic-AMP (10−5 to 10−3M) on gluconeogenesis from 5mM lactate was determined during incubation of hepatocytes from fed or fasted sucklings (S) (16 - 19 days old) and adult rats (A). Hepatocytes from fed sucklings had a blunted response to glucagon when compared to fed adult cells (% over basal, x ± S.E.M.: 50% ± 8 (S) vs 135% ± 15% (A). With fasting for 24 hours, the response to glucagon by adult cells was completely blunted, but not significantly affected in sucklings. When glucagon receptor was bypassed by stimulation of gluconeogenesis with exogenous Cyclic-AMP, a similar response as with glucagon was obtained. Dibutyril Cyclic AMP did not improve their response. Theophylline 10−3M increased by 25% the response to Cyclic-AMP of all groups but did not restore it to the level found in hepatocytes of fed adults. We conclude that the observed resistance to glucagon in suckling cells extends past the level of the receptor. The resistance to Cyclic-AMP is not primarily mediated through phosphodiesterase activity. A similar resistance is acquired when adult rats are fasted. Glucagon resistance in sucklings may reflect a similar cellular adaptation as that seen in adults when fasted and may be unrelated to their maturity. (Grant from Canadian MRC # MA - 6328)
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Beaudry, MA., Boodhoo, A. & Schiff, D. 221 GLUCAGON AND CYCLIC-AMP ACTION ON GLUCONEOGENESIS IN HEPATOCYTES FROM SUCKLING AND ADULT RATS. Pediatr Res 15 (Suppl 4), 476 (1981). https://doi.org/10.1203/00006450-198104001-00230
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DOI: https://doi.org/10.1203/00006450-198104001-00230