An extended developmental study of ?-glutamyltranspeptidase in rat liver plasma membranes: identification of specific patterns of changes in activity in the adult as well as the neonatal state

Sulakhe-Hemmings, Susan J.; Pulga, Vivian B.; Tran, Sam T.

doi:10.1007/bf00229098

Cited by 7 publications

(9 citation statements)

References 36 publications

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“…In accord with our previous findings [7,19,20], we show that this enzyme is expressed at low levels in the liver of rats fed the choline sufficient control diet and also that it is higher in females than in males. The response to the hepatocarcinogen diethylnitrosamine was found to be minimal in those rats on the choline sufficient control diet but markedly elevated in those on the choline deficient diet, coincident with the appearance of the hyperplastic premalignant nodules.…”

Section: Acceleration Of Hepatocarcinogenesis In the Ratsupporting

confidence: 79%

“…Following decapitation, blood was collected from the trunk of the rat , as we have done in the past [19][20][21][22], in chilled 50 ml beakers containing 70 µl of an anticoagulant solution containing 10.5 mg K + EDTA and 0.014 mg potassium sorbate. The whole blood was then centrifuged at 2000g at 4°C for 10 minutes.…”

Section: Preparation Of Samplesmentioning

confidence: 99%

“…Liver homogenate and plasma γGT activities were determined by our procedure using γ-glutamyl-ð-nitroanilide as substrate donor and glycylglycine as acceptor [7,[19][20][21][22]. Activity is expressed as nanmoles p-nitroaniline produced per min per mg liver homogenate protein or nanomoles p-nitroaniline produced per min per ml plasma.…”

Section: Assessment Of Samplesmentioning

confidence: 99%

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Administration of Diethylnitrosamine in the Immediate Postnatal Period Coupled with Exposure to a Choline Deficient Diet Accelerates Hepatocarcinogenesis in the Rat

Hemmings

Strickland²

2002

Cell Physiol Biochem

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The objectives of this study were to determine if the combination of: i. neonatal administration of diethylnitrosamine and ii. subsequent feeding of a choline deficient diet could accelerate hepatic premalignancy in the rat. The presence and size of premalignant nodules and the activity of the liver cancer enzyme marker g-glutamyltranspeptidase (gGT) were used as indicators of hepatic premalignancy. Three day old Fisher 344 rats were administered sc, saline or diethylnitrosamine (DENA): 100 mg/Kg. These were divided into choline sufficient (CS) and choline deficient (CD) groups with diets introduced to dams. On postnatal day 21 rats were weaned onto CS or CD diets. Rats in choline sufficient saline-injected (CS), choline sufficient DENA-injected (CS+DENA), choline deficient saline-injected (CD) and choline deficient DENA-injected (CD+DENA) groups were assessed on day 86. Livers of CS and CS+DENA rats were normal in appearance. Livers of CD rats were paler; those of CD+DENA rats contained visible, large, tan liver nodules. Identical results were observed in both sexes. Liver gGT activity was low and comparable in rats of CS and CS+DENA groups. Relative to liver homogenate gGT activity in the CS group, liver homogenate gGT was increased in the CD group: 14.5 fold in males and 18 fold in females; and further increased in the CD+DENA group: 78 fold in males and 54 fold in females. Plasma g-glutamyltranspeptidase exhibited the same trends as liver. The CD+DENA group demonstrated the largest increase in activity: 158 fold in males; 199 fold in females over that in the CS group. Male and female rats belonging to CS and CS+DENA groups were euthyroid; those in CD and CD+DENA groups were hypothyroid. Compared to hormone levels in the CS group, in the CD group, decreases in T3 were: 27% in males and 13% in females; decreases in T4 were: 29% in males and 5.6% in females. Compared to hormone levels in the CS groups, in the CD+DENA groups, decreases in T3 were: 25% in males and 18% in males; decreases in T4 were: 31% in males and 25% in females. Plasma glucose levels were comparable in rats of CS and CS+DENA groups. Relative to these levels, plasma glucose levels in rats of CD and CD+DENA groups were decreased 30% in males and females. Plasma transaminase levels were low and comparable in all groups. The protocol developed accelerated hepatocarcinogenesis in the Fischer 344 rat. In CD+DENA male and female rats, it produced, in 86 days, visible, large hyperplastic lesions displaying high levels of gGT and high levels of plasma gGT that are consistent with being at a well developed advanced premalignant stage of hepatocarcinogenesis without any sign of toxicity.

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Section: Acceleration Of Hepatocarcinogenesis In the Ratsupporting

confidence: 79%

Section: Preparation Of Samplesmentioning

confidence: 99%

Section: Assessment Of Samplesmentioning

confidence: 99%

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Administration of Diethylnitrosamine in the Immediate Postnatal Period Coupled with Exposure to a Choline Deficient Diet Accelerates Hepatocarcinogenesis in the Rat

Hemmings

Strickland²

2002

Cell Physiol Biochem

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“…In order to achieve these objectives, we chose the Fischer 344 rat, whose development we have studied 23,24 and exposure of these rats to either regular rodent chow or 10% flax chow from before birth until the 86th postnatal day. Ten per cent flax was chosen since reports in the literature ascribe beneficial results using this flax proportion.…”

Section: Introductionmentioning

confidence: 99%

“…19,20,[23][24][25] Results are expressed as nanomoles p-nitroaniline generated per ml plasma per minute (nmoles ml À1 min À1 ) for plasma, and nanomoles pnitroaniline generated per milligram protein per minute (nmoles mg À1 min À1 ) for liver fractions.…”

mentioning

confidence: 99%

The effects of dietary flaxseed on the Fischer 344 rat: I. Development, behaviour, toxicity and the activity of liver γ‐glutamyltranspeptidase

Hemmings

Barker

2003

Cell Biochemistry & Function

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The effect of exposure to, followed by consumption of, 10% flax chow from the 18th day of gestation to the 86th day after birth was examined in male and female Fischer 344 rats. Growth curves of the flax chow-fed rats were identical to those of regular chow-fed rats, as were such developmental milestones as pinna development, growth of hair and eye opening. Acoustical startle and the righting reflexes, developmental behavioural indices, were also the same. Blood glucose levels were comparable in flax chow-fed and regular chow-fed rats at all stages of development, indicating that flax is without effect on glucose balance. There were no signs of toxicity in the flax chow-fed rats since their plasma levels of alanine aminotransferase and gamma-glutamyltranspeptidase (gammaGT) were the same as those of regular chow-fed rats. The activity of gammaGT displayed an increase in the livers of flax chow-fed rats after puberty, more so in the male-four-fold-than in the female-1.38-fold. This is suggestive of an estrogenic effect which implicates an effect of an estrogenic flax lignan. An hepatobeneficial effect of the flax-induced increase in liver gammaGT is discussed. In summary, dietary 10% flax chow is without long-term effect on growth, development and behaviour, is non-toxic and may be hepatoprotective.

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The effects of dietary flaxseed on the Fischer 344 rat: II. liver γ‐glutamyltranspeptidase activity

Hemmings¹,

Westcott²,

Muir³

et al. 2004

Cell Biochemistry & Function

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The effect of 10% flax chow consumption from the 30th to the 130th day after birth was examined in male Fischer 344 rats. The effects of both the high lignan/high oil Norlin strain and a high lignan/low oil Solin strain of flaxseed were compared. Physically and behaviourally there were no differences in rats belonging to the three dietary groups at any time. At 50 and 100 days of dietary exposure, blood glucose levels were the same in Norlin and Solin flax chow-fed and as well as regular chow-fed rats; there were no signs of toxicity in the Norlin and Solin flax-fed rats since their plasma levels of alanine aminotransferase were the same and equal to those of regular chow-fed rats. The activity of gamma-glutamyltranspeptidase (gammaGT) displayed an increase in the liver homogenates of flax chow-fed rats. This increase was the same in Norlin and Solin flax-fed rats at 50 and 100 days. Thus the liver effect was not oil, but lignan, likely secoisolariciresinol diglucoside (SDG), induced and was effected early on, and sustained, after flax exposure. The degree of heat activation of liver homogenate gammaGT was the same in regular chow-fed and flax chow-fed rats. Compared to liver homogenate gammaGT activity, the soluble form of gammaGT was expressed at very low levels while the plasma membrane-bound form of gammaGT was expressed at very high levels in rat liver in both regular chow-fed and flax chow-fed rats. There was no effect of flax feeding on the soluble form of liver gammaGT which was expressed at a very low level. Flax feeding effected an increase in the activity of gammaGT in isolated plasma membrane fractions which mirrored that in liver homogenates: the same degree of increase was seen in Norlin flax chow-fed and Solin flax chow-fed rats. Flax consumption effects an increase in the activity of liver gammaGT at the level of the plasma membrane which is lignan dependent, physiologically relevant and may be linked to hepatoprotection against injury through an increase in reduced glutathione.

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An extended developmental study of ?-glutamyltranspeptidase in rat liver plasma membranes: identification of specific patterns of changes in activity in the adult as well as the neonatal state

Cited by 7 publications

References 36 publications

Administration of Diethylnitrosamine in the Immediate Postnatal Period Coupled with Exposure to a Choline Deficient Diet Accelerates Hepatocarcinogenesis in the Rat

Administration of Diethylnitrosamine in the Immediate Postnatal Period Coupled with Exposure to a Choline Deficient Diet Accelerates Hepatocarcinogenesis in the Rat

The effects of dietary flaxseed on the Fischer 344 rat: I. Development, behaviour, toxicity and the activity of liver γ‐glutamyltranspeptidase

The effects of dietary flaxseed on the Fischer 344 rat: II. liver γ‐glutamyltranspeptidase activity

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