The metabolism of radioactive glucose in vitro has been compared in anterior pituitary tissue (AP) from male and female rats. The pathways leading to the major products of glucose metabolism in AP, CO2, lactate, protein and amino acids, were equally active in the 2 sexes when expressed per unit weight of tissue. The female AP is 1.5-fold heavier than the male AP, however, and therefore the total metabolic activity of the AP is correspondingly greater in females of comparable body weight. Glucose assimilation by AP was increased with increasing concentrations of medium glucose. The fraction of assimilated glucose converted to the various products measured changed as the concentration of medium glucose was increased. At a concentration of medium glucose of 1.0 mg/ml, 24% of assimilated glucose was converted to amino acids, peptides and protein in both sexes. A comparable amount was oxidized to CO2, and much smaller fractions were recovered in glycogen and lipid. Male and female differences in glycogen synthesis, glycogen content and incorporation of glucose 14C into alanine, aspartic acid and an unidentified peptide were noted. The activity of the pentose cycle was measured, and in both sexes the contribution of this pathway was small (less than 5 %). The contribution of the pentose cycle was probably less in female AP compared to male AP at 2 concentrations of medium glucose. The similar pattern of carbohydrate metabolism in AP from the 2 sexes despite differing histologic composition suggests that the basic cell types within the anterior pituitary may share a common metabolic background to which are appended specialized functions of tropin elaboration. The quantitatively minor differences noted might equally reflect differences in hormonal environment, the state of hypothalamic activity or intrinsic metabolic differences in specific cell types. (Endocrinology75: 846,1964)