Hepatic acetogenesis and ketogenesis in neonatal swine

Adams, Sean Harrison

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https://hdl.handle.net/2142/22459 Copy

Description

Title

Hepatic acetogenesis and ketogenesis in neonatal swine

Author(s)

Adams, Sean Harrison

Issue Date

1994

Doctoral Committee Chair(s)

Odle, Jack

Department of Study

Food Science and Human Nutrition

Discipline

Food Science and Human Nutrition

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

Ph.D.

Degree Level

Dissertation

Keyword(s)

• Biology, Animal Physiology
• Health Sciences, Nutrition

Language

eng

Abstract

Reports of low circulating ketone bodies ($\beta$-hydroxybutyrate, $\beta$-OHB & acetoacetate) in suckling piglets and evidence of minimal hepatic ketone body production from fatty acids in vitro suggested that, unlike previously-studied neonates, enhanced ketogenesis does not characterize the metabolism of the newborn pig. This apparent idiosyncracy of piglet metabolism prompted a series of studies examining development and regulation of ketogenesis in piglets, and the physiological implications of low ketonemia in piglets. The extent of alternative pathways (non-ketogenic routes of carbon flux into Krebs cycle intermediates, e.g.) of fatty acid $\beta$-oxidation was also assessed. Low ketogenic capacity in piglets was confirmed by the small change in plasma ($\beta$-OHB) relative to (C8:0) (regression slope) following a dose of C8:0. This slope was 1-2 orders of magnitude lower vs. that of mature pigs and newborn or mature rabbits. Minimal fatty acid carboxyl-carbon accumulated in ketone bodies after incubations of piglet liver homogenates or hepatocytes with (1-$\sp{14}$C) -C7:0, -C8:0, or -C16:0 in vitro, consistent with the in vivo results. The observed low activity of the ketogenic enzyme mitochondrial 3-hydroxy-3-methylglutaryl-CoA synthase (HMG-CoA synthase) increased plasma (insulin) with suckling (patterns opposite that seen in ketotic neonatal rats, e.g.) may in part explain attenuated ketogenic capacity in piglets. Piglets accumulated fatty acid carboxyl-carbon in acetate to a high degree relative to ketone bodies in incubations of liver tissue with radiolabeled fatty acids, a phenomenon previously unreported for any animal. It is thus speculated that acetate plays a more important physiological role than the ketone bodies in newborn piglets, an idea supported by the small contribution of ketone bodies to the energy budget of piglets ($<$3% of metabolic rate from ketone bodies at normal physiological plasma ($\beta$- OHB)), and the 10-fold higher plasma (acetate) relative to the (ketone bodies) in piglets.

Type of Resource

text

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http://hdl.handle.net/2142/22459

Copyright and License Information

Copyright 1994 Adams, Sean Harrison

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