Pentti K. Siiteri (University of California at San Francisco) reported that DHEA inhibits triglyceride (blood fat) synthesis in a mouse model system by about 10%, reduces fatty acid synthesis by two-thirds, and inhibits prolactin synthesis by about 70-90% (an effect which should protect against breast cancer).

In related work, Gary Gordon (G.D. Searle, Skokie, 1L) reported that DHEA at a concentration of 60-240 micromolar also powerfully inhibited the maturation of pre-adipocytes (would-be fat cells) into full-fledged fat cells in tissue culture. At the same time, according to Siiteri, DHEA causes proteins related to "fat burning" to be made in greater amounts, including carnitine acetyl-CoA transferase. This appears to be one of the most central biochemical effects of DHEA.

Perhaps the latter effect helps to make up in some way for another rather shocking finding of Siiteri's, namely, that the number of mitochondria (energy-producing units) per unit volume of cytoplasm (cell sap) fell by half and that each remaining mitochondrion was smaller in the rat liver after DHEA administration. (Perhaps this loss of mitochondrial mass is a significant but previously unknown reason why animals given DHEA lose weight. In any case, it does not seem to cause any problems.) Interestingly, Siiteri found that DHEA also raised catalase levels by 50-100%. His only negative finding was that, alas, DHEA also increased cholesterol synthesis by about 50%.