Fig. 4. The levels of HSP70 and HSP90, and putative HIF in the last two developmental stages studied (3, Gosner stage 39; and 4, Gosner 42). For all proteins the level increases significantly (P<0.05) from stage 3 to stage 4. Values are means and s.e.m. (indicated as lines above the bars). The number of tadpoles was seven for developmental stage 3 and ten for stage 4 in the case of HSP70; four and nine, respectively, for HSP90, and five and 37, respectively, in the case of putative HIF.