Enzymatic adaptations in newborn pig liver

Swiatek, Kenneth R.; Chao, Kuen-Lan; Chao, Hsiang-Lin; Cornblath, Marvin; Tildón, J. Tyson

doi:10.1016/0304-4165(70)90359-4

Cited by 23 publications

(9 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In late gestation (80-90 %) the hepatic glycogen content and the activities of G6Pase and PEPCK in the liver and kidney of the fetal pig were higher than those in most other species at a similar stage of gestation (Ballard & Hanson, 1967;Jones & Ashton, 1976;Callikan & Girard, 1979;Susa, Gruppuso, Widness, Domenech, Clemons, Sehgal & Schwartz, 1984;Fowden et al 1991Fowden et al , 1993. The glucogenic capacity of the fetal pig therefore appears to be high compared with that of other species in late gestation, which is consistent with the relatively low fat content of the piglet and its greater dependence on glucose as a metabolic fuel in the immediate postnatal period (Swiatek et al 1970;Randall, 1978;Mellor, 1988).…”

Section: Discussionsupporting

confidence: 61%

“…However, nothing is known about the effects of such treatment on gluconeogenic enzyme maturation, although hepatic glucose-6-phosphatase (G6Pase) activity is known to rise at birth in this as in other species (Swiatek, Chao, Chao, Cornblath & Tildon, 1970;Mersmann, 1971;Fowden et al 1992). Therefore, in the present study the effects of a 6 day infusion of cortisol on gluconeogenic enzyme activities in liver and kidney were investigated in immature fetuses and compared with the normal ontogenic changes in enzyme activity that occur in late gestation and at birth.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

The glucogenic capacity of the fetal pig: developmental regulation by cortisol

Fowden¹,

Apatu²,

Silver³

1995

Experimental Physiology

View full text Add to dashboard Cite

SUMMARYIn the present study, the ontogenic changes in gluconeogenic enzyme activities and in hepatic glycogen and ,-adrenergic receptor levels were investigated in fetal pigs from 70 days of gestation until delivery at term (114 + 2 days). The values were compared with those observed in fetuses infused subcutaneously with cortisol for 6 days beginning at 82-84 or 92-94 days of gestation. Tissue glucose-6-phosphatase (G6Pase) activity increased with increasing gestational age in the liver, kidney and duodenum of control fetal pigs. At birth, there was a further increase in G6Pase activity in the liver but not in the kidney or duodenum. In the kidney, there was a similar gestational increase in phosphoenolpyruvate carboxykinase (PEPCK) activity. These changes in enzyme activities closely paralleled the prepartum increase in fetal plasma cortisol and were accompanied by increases in hepatic glycogen content and f-adrenergic receptor density. At 98-100 days, there were significant increases in G6Pase activity in the liver, kidney and duodenum of the cortisol-infused fetuses, whereas at 88-90 days only renal G6Pase was significantly elevated by cortisol infusion. Cortisol infusion also increased hepatic ,-receptor density at 88-90 days and hepatic glycogen content at both gestational ages. There were no changes in hepatic PEPCK, hepatic or renal fructose diphosphatase and aspartate amino transferase activities during cortisol infusion or with increasing gestational age. When the data from all the piglets were combined, irrespective of age or treatment, there were significant positive correlations between log plasma cortisol and G6Pase activity in the liver, kidney and duodenum. Similar positive correlations were observed between hepatic ,/-adrenoceptor density and log plasma cortisol and between the latter values and the hepatic glycogen content. These findings show that cortisol induces tissue G6Pase activity in the fetal pig and suggest that the prepartum rise in endogenous cortisol may be responsible for the increase in fetal glucogenic capacity observed towards term in this as in other species.

show abstract

Section: Discussionsupporting

confidence: 61%

Section: Introductionmentioning

confidence: 99%

The glucogenic capacity of the fetal pig: developmental regulation by cortisol

Fowden¹,

Apatu²,

Silver³

1995

Experimental Physiology

View full text Add to dashboard Cite

show abstract

“…Previous findings show that hepatocytes isolated from 2-to 3-wk-old piglets manifest the complete gluconeogenic/glycolytic enzymatic machinery similar to that found in the larger pigs. Furthermore, it is well established that the isolation of intact, viable hepatocytes from 2-to 3-wk-old piglets is more likely than with larger pigs (13,15,40). Thus, while we acknowledge the potential for an age effect, we think it unlikely that species differences noted herein simply reflect the age of each animal model.…”

Section: Discussionmentioning

confidence: 79%

Regulation of hepatic glucose metabolism by leptin in pig and rat primary hepatocyte cultures

Raman

Donkin

Spurlock

2004

American Journal of Physiology-Regulatory, Integrative and Comp

View full text Add to dashboard Cite

Direct effects of leptin on gluconeogenesis in rat hepatocytes are equivocal, and model systems from other species have not been extensively explored in assessing the regulation of glucose metabolism by leptin. Therefore, the goal of the present study was to compare the effects of leptin on gluconeogenesis in pig and rat hepatocyte cultures as well as to investigate an underlying mechanism of action at the level of phosphoenolpyruvate carboxykinase (PEPCK). In rat hepatocytes, leptin exposure (3 h, 50 and 100 nM) attenuated glucagon-stimulated hepatic gluconeogenesis by 35 and 38% (P < 0.05), respectively. However, leptin did not produce any significant acute effect in pig hepatocytes. Leptin exposure for 24 h failed to produce any significant effect on gluconeogenesis in either rat or pig hepatocytes cultured in the presence of glucagon or dexamethasone. Mechanistically, there was a 25-35% decrease (P < 0.05) in glucagon-induced PEPCK mRNA levels in rat but not pig hepatocytes cultured with leptin. This effect on PEPCK mRNA was not due to an alteration in the relative abundance of the leptin receptor or the ability of PEPCK to respond to cAMP. The nonuniformity of the effects of leptin on gluconeogenesis in pig and rat hepatocytes indicates differences in leptin action between species. Furthermore, the unique action of leptin in porcine hepatocytes points to the utility of this model system for biomedical research and also underscores the value of comparative studies.

show abstract

“…In addition, plasma GH concentrations continuously increase as newborn pigs are fasted, whereas GH concentrations in older pigs increase and plateau during early periods of fasting (Swiatek et al, 1968b). Others (Swiatek et al, 1968a;Mersmann and Phinney, 1973;Curtis, 1974) have demonstrated that gluconeogenesis, fatty acid oxidation and temperature regulation, which are defective in newborn pigs, are ameliorated by 3 days of age. Lower GH concentrations in newborn Ossabaw pigs may indicate advanced metabolic maturity; however, the metabolic significance of lower plasma GH is not evident.…”

Section: Resultsmentioning

confidence: 99%

Fasting Plasma Hormones and Metabolites in Feral and Domestic Newborn Pigs

Kasser

Martin

Gahagan

et al. 1981

Journal of Animal Science

View full text Add to dashboard Cite

Newborn Yorkshire and Ossabaw (feral) pigs were examined under thermoneutral conditions to determine whether survival rate during fasting differs between these breeds and whether any blood-borne factors are associated with improved survival. Newborn pigs were removed from the sow before suckling. Body composition was determined on 10 newborn Ossabaw and 12 newborn Yorkshire pigs. Another group of animals (eight Ossabaw, 12 Yorkshire) was fasted for 72 hr, with blood samples drawn at birth and 12 and 24 hr into fasting. Glucose, free fatty acid (FFA), growth hormone (GH), insulin, thyroxine (T4), triiodothyronine (T3), cortisol and glucagon concentrations were measured in plasma of fasted pigs. Concentrations of carcass lipid, dry matter and ash were higher in newborn Ossabaw pigs than in newborn Yorkshire pigs. Survival through 72 hr of fasting was lower among Yorkshire pigs. Yorkshire and Ossabaw pigs had similar concentrations of metabolites and hormones at birth, with the exceptions of lower plasma GH and higher T3 concentrations in Ossabaw pigs. Higher plasma T3 concentrations would indicate a greater potential for fatty acid oxidation. During fasting, Ossabaw pigs had lower plasma GH and T4 concentrations and higher glucagon and FFA concentrations. Increased survival among newborn Ossabaw pigs may have been due to increased availability of FFA during fasting, and to a greater potential for gluconeogenesis through increased oxidation of fatty acids and higher plasma glucagon concentrations. This would suggest that maternal treatments that would increase storage of fat and(or) increase the capacity for oxidation of fat in utero would improve survival of newborn pigs.

show abstract

Enzymatic adaptations in newborn pig liver

Cited by 23 publications

References 20 publications

The glucogenic capacity of the fetal pig: developmental regulation by cortisol

The glucogenic capacity of the fetal pig: developmental regulation by cortisol

Regulation of hepatic glucose metabolism by leptin in pig and rat primary hepatocyte cultures

Fasting Plasma Hormones and Metabolites in Feral and Domestic Newborn Pigs

Contact Info

Product

Resources

About