3.33 (3 votes) In earlier studies, researchers at Louisiana State University had found that estrogen - or more precisely, having ovaries - made adult rats exposed for the first time to THC, the primary ingredient in marijuana and hashish, less sensitive to THC's negative effects on tests of learning and memory. A new study, reported at the Experimental Biology 2009 meeting in New Orleans, finds that when rats are first exposed to THC during the equivalent of adolescence, however, estrogen loses its protective effect. When these rats were again exposed to THC as adults, they performed more poorly on tests of learning and memory - diminished response time,cheap trx suspension trainer, increase in errors - than did similar rats that had not been exposed to THC when younger. Dr....