Capacity for substrate utilization in oxidative metabolism by neurons, astrocytes, and oligodendrocytes from developing brain in primary culture

Abstract

Neuron, astrocyte, and oligodendrocyte cultures which were established from developing rat brain were examined for their utlization of glucose, ketone bodies, and free fatty acids by oxidative processes. ¹⁴CO² production was measured in these cells from [1-¹⁴C] or [6-¹⁴C]glucose; [1-¹⁴C] and [1-¹⁴C], [6-¹⁴C], or [6-¹⁴C]palmitate; and [3-¹⁴C]acetoacetate and D(-)-3-hydroxy[3-¹⁴C]butyrate. Pyruvate dehydrogenase (EC 1.2.4.1.) abd 3-oxoacid-CoA transferase (EC 2.8.3.5.) activites were found at high levels in each of the cell population. Astrocytes and oligodendrocytes produced much more ¹⁴CO² from [1-¹⁴C]glucose than from [6-¹⁴C]glucose, indcating substantial hexose monophosphate shunt activity. This process was not as active in neurons. All three cell populations readily utilized the ketone bodies for oxidative metabolism at rates 7–9 times greater than they utilize glucose. Only astrocytes were able to utilize fatty acids for ¹⁴CO² production, and the rate of utilization was greater than of the ketone bodies. We found that the metabolic patterns of thesse brain cells which were derived from the developing brain complement the nature of the diet of the duckling animal which is rich fat and low in carbohydrate. They readily utilized the ketone bodies or fatty acids and spared glucose for processes that metabolites of fat cannot fulfill.