Relationship between Propionate Metabolism and TCA cycle in Mammary Gland Slices of Normal, Starved and Alloxan Diabetic Sheep

Abstract

This study was designed to elucidate the relationships between the propionate metabolism and TCA cycle in mammary gland, and how the relationships were influenced by starvation and alloxan treatment. The following results were obtained in a study of the influence of citrate or succinate on the ¹⁴C-propionate metabolism and those of propionate on the metabolism of ¹⁴C-citrate or ¹⁴C-succinate in mammary gland slices of normally fed, starved and alloxan diabetic sheep.
In normal and starved condition, the ¹⁴C-propionate consumption and the transfer of ¹⁴C from IT-propionate into CO₂ and lipid increased by the addition of citrate and succinate. The consumption of ¹⁴C-citrate and ¹⁴C-succinate and the transfer of ¹⁴C from ¹⁴C-citrate and ¹⁴C-succinate into CO₂ and lipid decreased by the propionate addition. Effects of citrate and succinate on the propionate metabolism and those of propionate on the metabolism of citrate or succinate in starved condition were larger than the cases of normal condition. Effects of citrate on the propionate metabolism and those of propionate on the citrate metabolism disappeared following treatment of alloxan. But the effects of succinate on the propionate metabolism were observed in alloxan diabetes, and the effects of succinateon the propionate metabolism and those of propionate on the succinate metabolism were larger than the case of normal and starved condition.
As mentioned above, there were some relationships between the propionate metabolism and TCA cycle, and these relationships changed due to starvation and alloxan treatment.(Supported by NIH grant HD 02375)