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Role of fructose 2,6-bisphosphate in mammary gland of fed, starved and re-fed lactating rats.

ABSTRACT: The fructose 2,6-bisphosphate (Fru-2,6-P2) content and intracellular concentration of lactating mammary gland was measured in fed, starved and re-fed rats. There was little or no change on starvation, and about 1.5-fold rise on re-feeding, contrasting with estimated glycolytic changes of about 10-fold. The 6-phosphofructokinase (PFK-1) activity of mammary extracts was highly sensitive to added Fru-2,6-P2 under all conditions examined, and appeared to approach saturation at physiological concentrations of this effector. The activity of mammary PFK-1 measured under optimal and 'physiological' conditions suggested that this enzyme operates in vivo at about 24% of maximal rate, and is likely to be an important rate-limiting factor in mammary glycolysis.

SUBMITTER: Ward S

PROVIDER: S-EPMC1152973 | biostudies-other | 1985 Dec

REPOSITORIES: biostudies-other

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Arteriovenous glucose differences across the mammary gland of the fed, starved, and re-fed lactating rat.

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