This study examined 188 preservice science teachers' professional growth along three dimensions--self-regulated learning (SRL) in a science pedagogical context, pedagogical content knowledge, and self-efficacy in teaching science--comparing four learner-centered, active-learning, peer-collaborative environments for learning to teach higher order scientific-inquiry thinking. Three environments supported different SRL components using the "IMPROVE" self-regulatory model: cognitive-metacognitive alone (CogMet), motivational alone (Mot), or all three components (CogMetMot). The fourth environment provided no SRL support. Findings indicated that preservice teachers in the three SRL-scaffolding conditions outperformed their unscaffolded peers on all professional growth measures: SRL (cognition, metacognition, motivation), pedagogical knowledge (declarative, procedural, conditional), and self-efficacy in teaching science. Moreover, the CogMetMot group exhibited the highest scores on all measures. Implications concern SRL scaffolding to enhance preservice science teachers' professional growth. (Contains 6 tables.)