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Diffuse melanosis of the epithelial lining of an unusually large median raphe cyst of the penis is reported. Its light microscopic and ultrastructural features are described. The findings are discussed in the context of the published literature of genitourinary melanosis.

The hypothesis that heat shock protein (HSP) induction depends on inhibition of respiration was tested by examining the effects of heat shock o n tricarboxylic acid (TCA) cycle function. In control L929 cell cultures, glucose and exogenous pyruvate were converted primarily to lactate, and glutamine was extensively oxidized, accounting for more than one-half of the calculated ATP production. During heat shock at 42OC, lactate production from all of t h e labeled substrates and total unlabeled lactate production increased significantly while oxygen consumption increased slightly. TCA cycle oxidation of pyruvate decreased during this period while that of glutamine increased. Uncoupling of oxidative phosphorylation caused large increases in oxygen consumption at both 37OC and 42OC, indicating that the capacity of the respiratory chain is not exceeded during heat shock. The net effect of these alterations in substrate utilization were decreased ATP generation and increased NADH utilization. Both I4CO2 and lactate production declined during the 24-h period after cultures were returned to 37OC. On the basis of these data, we conclude that while inhibition of respiration plays no apparent role, other metabolic consequences of heat shock related to energy metabolism may be involved in HSP induction.Although the heat shock response results in dramatic induction of specific proteins and can easily be evoked in cultured cells, the mechanism responsible for activation of the underlying genes is still unknown. The problem is being approached from several directions, including sequencing of the genetic regulatory elements (Hackett and Lis, 1981;Mason et al

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