Role of the availability of substrates on hepatic and renal gluconeogenesis in the fasted late pregnant rat

Journal Article · Tue Apr 01 04:00:00 EST 1986 · Metab., Clin. Exp.; (United States)

DOI:https://doi.org/10.1016/0026-0495(86)90144-7· OSTI ID:5810210

Zorzano, A; Lasuncion, M A; Herrera, E

Studies were conducted to examine the role of gluconeogenetic substrate availability on glucose production in the fasted late pregnant rat. Virgin and 21-day pregnant rats were studied after 24 hours' food deprivation. Pregnant animals showed decreased circulating glucose and gluconeogenic amino acid and increased plasma glycerol concentration. Glucose formation was studied in vivo two, five, and ten minutes after the intravenous administration of two concentrations of /sup 14/C-alanine, /sup 14/C-pyruvate, or /sup 14/C-glycerol. Concentrations of 0.2 mmols of /sup 14/C-glycerol or /sup 14/C-pyruvate, but not of /sup 14/C-alanine, enhanced /sup 14/C-glucose production in pregnant rats, whereas 1 mmol of any of the three /sup 14/C-substrates always enhanced /sup 14/C-glucose production in these rats. Both 1 mmol/L and 5 mmol/L /sup 14/C-alanine increased /sup 14/C-glucose formation in 90-minute-incubated liver slices of fasted pregnant rats, in spite of decreased cytosolic activity of alanine aminotransferase. The three substrates enhanced in vitro renal gluconeogenesis in pregnant rats. Under all experimental conditions studied, labeled glycerol was converted more efficiently into glucose than equivalent amounts of any other substrate used, and this difference was greater in pregnant, than in virgin animals. Results indicate that, in spite of enhanced gluconeogenetic activity, maternal glucose production in the fasted state at late gestation is limited by the deficiency of certain substrates, such as amino acids. It is proposed that glycerol derived from enhanced maternal adipose tissue lipolysis constitutes a preferential gluconeogenetic substrate in comparison with others, such as alanine, that are more efficiently transferred through the placenta to the fetus.

• Research Organization: Centro Ramon y Cajal, Madrid, Spain
• OSTI ID: 5810210
• Journal Information: Metab., Clin. Exp.; (United States), Journal Name: Metab., Clin. Exp.; (United States) Vol. 4; ISSN METAA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ALANINES
ALCOHOLS
ALDEHYDES
AMINO ACIDS
AMINOTRANSFERASES
ANIMALS
BIOLOGICAL AVAILABILITY
BIOSYNTHESIS
BODY
CARBOHYDRATES
CARBON 14 COMPOUNDS
CARBOXYLIC ACIDS
DIGESTIVE SYSTEM
ENZYMES
FASTING
GLANDS
GLUCOSE
GLYCEROL
HEXOSES
HYDROXY COMPOUNDS
IN VITRO
ISOTOPE APPLICATIONS
KETO ACIDS
KIDNEYS
LABELLED COMPOUNDS
LIVER
MAMMALS
MONOSACCHARIDES
NITROGEN TRANSFERASES
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANS
PREGNANCY
PYRUVIC ACID
RATS
RODENTS
SACCHARIDES
SUBSTRATES
SYNTHESIS
TRACER TECHNIQUES
TRANSFERASES
VERTEBRATES