Effects of insulin and anti-insulin serum treatments on levels of metabolites in rat mammary glands.

Abstract

The metabolic lesions produced by insulin insufficiency in lactating Sprague-Dawley rats were characterized. Guinea pig anti-insulin serum was used to produce acute insulin insufficiencies in lactating rats. Metabolite level changes in mammary tissue of animals receiving anti-insulin serum were observed. These changes were discussed in relation to activities of the Embden-Meyerhoff and pentose phosphate pathways. Calculations of the redox state of free nicotinamide adenine dinucleotides indicated that insulin insufficiency produced a shift in the redox state in mammary tissue. In addition, acute diabetes resulted in a decrease in the proportion of high energy phosphate bonds to the total adenine nucleotides in mammary tissue. These observations suggest that insulin's influence on mammary tissue metabolism was manifested primarily through its effects upon the redox state of free nicotinamide adenine nucleotides. This effect could possibly be attributed to reduced activity of the electron transport system. ...