No abstract

The amount of milk available to each member of the litter was varied by adjusting the number of mice pups to 4, 8 or 12 per dam. The total fatty acid content of the carcass of the young increased for 2 weeks, and there was more in the well-fed groups. The fatty acid contents decreased thereafter transiently in all groups until weaning. The milk diet contributed major quantities of lauric and myristic acids to peripheral tissues but not to the liver. Undernourishment during neonatal life was associated with a relative reduction in palmitoleic, oleic and linoleic acids in l·ipids of the carcass. In contrast the carcass of the progeny subjected to overall dietary abundance showed relative increase in palmitoleic, oleic and linoleic acids at the expense of stearic acid.

1. Lipid metabo dism was fo llo wed fo r 7 days in Ican and o bese-hyperglyceniic 11-week o ld Bar Harb o r mice by measuring tiie inc o rp o rati o n o f a single d o se (90 fiC) o f [l-l^C] acétate in the liver and extrahepatic tissues. 2. In the liver of control animais, microsomes were more active (han supernatant with respect to lipogenesis at timc 10 min. They were also more efficient in desaturating lab elled 18 :0 than 16 : 0. A portion of unlal)eMed fatty acid was elongated with [l-WC] acétate. The radioactivity of liver glyccrides dccrcased rapidly b ecause of the sécrétion of lipoproteins rich in lab elled 18 : 1. The turnover at the 2-position in triglycérides remaining in the liver appeared to b e slower than at positions 1 and 3. 3. In the adipose tissue, the renewal of 1-2 diglycerides was very rapid. The lab elling of 1-3 diglycerides in this tissue suggests the existence of a monoglyceride pathway opcrative in niuo. Triglycérides were b etter lab elled in muscle than in adipose tissue. 4. In ail tissues, the secondary altérations in the structure of « precursor » triglycérides .ind phospholipids during the 7-day period indicate that a sizeab le proportion was su bmitted to either complète or partial lipolysis. Transfers of ''^C hy elongation and/or desaturation occurred in the newly relcased fatty acids b efore acyl rearrangements, as a resuit the divergences b etween distri b ution and lipid structures o b served at time 10 min were slowly reduced. 5. In ob ese-hyperglycemic mice twice as much of the radioactivity otïcred was incorporated into total b ody lipids. The liver was the chief lipogenetic site, with microsomes as well as supernatant overloaded with radioactive triglycérides. The microsomal 9,10 dehydrogenase was very active, and the 2-position of triglycérides was dominated b y la b elled 18 : 1 throughout the experiment. 6. Both, the renewal of adipose tissue 1-2 diglycerides and the radioactivity of muscle triglycérides were higher than in lean littermates.

No abstract