Evidence for Increased Fatty Acid Transfer across the Placenta during a Maternal Fast in Rabbits

Edson, José; Hudson, D.G.; Hull, D

doi:10.1159/000240758

Cited by 61 publications

(33 citation statements)

References 2 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In the present study, the rabbits did not increase food intake throughout pregnancy (Fig. 2) in agreement with previous data (6,21,42). In fact, food intake was reduced by about 15% for the last 4 days of gestation, similar to the rat in which the food intake drops by 15-20% 2 days before term (10,20,38).…”

Section: Discussionsupporting

confidence: 94%

Some Aspects of Maternal Metabolism Throughout Pregnancy in the Conscious Rabbit

1984

View full text Add to dashboard Cite

SummaryStudies of maternal metabolism during pregnancy have focused principally upon the latter half of gestation. However, maternal metabolic adaptations to pregnancy may occur at all stages of pregnancy. To study maternal metabolism throughout pregnancy, we developed a chronically catheterized rabbit model in which animals could be studied under conscious, stress-free conditions when nonpregnant and then serially throughout pregnancy.Anesthesia produced marked hyperglycemia. In contrast, chronic catheterization and daily handling did not affect blood concentrations of glucose, lactate, ketone bodies, or free fatty acids, or food intake. Glucose concentration decreased with pregnancy to a value at term equal to 85% of the prepregnancy value. Lactate concentration rose significantly in the second half of pregnancy but changes in free fatty acids and ketoacid levels were not significant. These results are discussed from a comparative physiologic point of view, emphasizing the unique aspects of rabbit metabolism during pregnancy and the importance of performing such studies under conscious, stress-free conditions.The impact of pregnancy upon maternal metabolism of carbohydrates and lipids has been studied in the rat (14,20), guinea pigs (I I, 37), and man (8,18,30). In these species, most studies were performed over the latter third of gestation. It is probable that the timing and the magnitude ofmaternal metabolic changes during pregnancy may be related to such factors as the growth rate of the fetus and the placenta, the fetal and placental mass and metabolic rate at different stages of pregnancy, and the maternal diet. In particular, animal species with a relatively short gestation that produce a large fetal to maternal mass ratio at term (i.e., guinea pig, 0.50; rat, 0.17; and rabbit, 0.15) are of interest with regard to the maternal metabolic changes which occur during the entirety of gestation.The majority of metabolic studies during pregnancy have involved surgical, anesthetic, and handling stress. In particular, in the rabbit there have been no studies describing maternal metabolism at any time of pregnancy under chronic, stress-free, steady state conditions. The present paper describes our results in developing techniques for chronic catheterization of rabbits prior to pregnancy, permitting metabolic studies in the conscious

show abstract

Section: Discussionsupporting

confidence: 94%

Some Aspects of Maternal Metabolism Throughout Pregnancy in the Conscious Rabbit

1984

View full text Add to dashboard Cite

show abstract

“…This indeed may have been a complicating factor and we did not control for it, though we think its significance is minor relative to the size of the effect we observed (no increase in FFA for the first 2 h after the DEX injection; a 13-fold increase in FFA 30 min after the ACTH injection). In contrast, in an experiment by Edson et al (1975), fasting female rabbits for 48 h resulted in only a 2-fold increase in FFA levels. Thus we think the length of the fasting our rabbits experienced was too short to have had a significant impact on our results.…”

Section: Discussionmentioning

confidence: 76%

Increased corticosteroid binding capacity of plasma albumin but not of corticosteroid-binding globulin caused by ACTH-induced changes in free fatty acid concentrations in snowshoe hares and rabbits

Boonstra

Tinnikov²

1998

Journal of Endocrinology

View full text Add to dashboard Cite

Free fatty acids (FFAs) are rapidly mobilized by ACTH and have been shown to be potent endogenous modulators of steroid-protein interactions. We increased FFA in lagomorphs by ACTH and then separated the transient increase in glucocorticoid binding capacity of plasma into that accounted for by changes in binding to albumin and to corticosteroid-binding globulin (CBG). Sequential injections of dexamethasone and ACTH into both snowshoe hares and laboratory rabbits resulted in the rapid mobilization of FFA only after the ACTH injection. The maximum corticosteroid binding capacity increase paralleled that of the FFA increase in both species. In rabbits, CBG levels remained constant over the duration of the experiment. Corticosterone binding by rabbit albumin increased in a dose-dependent fashion in response to increases in FFA (oleic and linoleic acid) concentrations. Finally, by stimulating FFA release in snowshoe hares with ACTH and separating the increase in corticosteroid binding capacity through selective denaturing of CBG by heat, we determined that the increase in plasma binding capacity was a response to changes in binding by albumin, not CBG. Thus FFA released in response to stressors in lagomorphs may effect short-term increases in steroid binding.

show abstract

“…In previous investigations (Edson et al 1975;Elphick et al 1976) we demonstrated a rapid flux across the placenta of FFA with prevailing maternal levels determining the net flow to the foetus. This investigation has extended these observations by examining the differences in the transport across the rabbit placenta of the main fatty acids present in foetal adipose tissue.…”

Section: Checking Experimentsmentioning

confidence: 75%

The transfer of free fatty acids across the rabbit placenta.

Elphick¹,

Hull²

1977

The Journal of Physiology

View full text Add to dashboard Cite

SUMMARY1. The passage of fatty acids across the placenta was studied in 28 day pregnant rabbits (i) by comparing the fatty acid distribution in plasma free fatty acids (FFA) of umbilical cord artery and vein with that in maternal plasma and (ii) by infusing the doe at a constant rate with labelled palmitic, linoleic or arachidonic acids. During the infusion maternal and foetal plasma FFA specific activities were measured.2. The mean levels of all the fatty acids studied (from twelve to twenty carbon atoms) were similar in both the umbilical vein plasma and maternal arterial plasma FFA, except for arachidonic acid, which was higher in foetal blood. The relative distribution of the fatty acids in umbilical arterial plasma was similar to that in the vein, but at lower concentrations. The mean cord venous-arterial difference for each fatty acid correlated positively with the mean maternal arterial levels, with the exception of arachidonic acid.3. During the constant infusion experiments the specific activities of the fatty acids in the maternal and foetal circulating FFA pools rose rapidly during the first 4 min then rose only slowly. Palmitic and linoleic acids were cleared from the maternal circulation in a similar manner and crossed the placenta at similar rates.4. The average foetal specific activity in plasma FFA reached 15 % of the maternal level for both palmitate and linoleate. The figure for arachidonic acid was half that for palmitic acid infused at the same time.5. It is concluded that (i) all the major fatty acids present in foetal adipose tissue cross the placenta, (ii) the net transport of each fatty acid depends in part on maternal concentrations, (iii) the rate of metabolism of palmitic and linoleic acids is the same and both cross the placenta at the same rate. Proportionately less foetal arachidonic acid is derived from maternal FFA, and (iv) the results suggest a second placental source of arachidonic acid and possibly also of other fatty acids.

show abstract

Evidence for Increased Fatty Acid Transfer across the Placenta during a Maternal Fast in Rabbits

Cited by 61 publications

References 2 publications

Some Aspects of Maternal Metabolism Throughout Pregnancy in the Conscious Rabbit

Some Aspects of Maternal Metabolism Throughout Pregnancy in the Conscious Rabbit

Increased corticosteroid binding capacity of plasma albumin but not of corticosteroid-binding globulin caused by ACTH-induced changes in free fatty acid concentrations in snowshoe hares and rabbits

The transfer of free fatty acids across the rabbit placenta.

Contact Info

Product

Resources

About