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The challenge for any teacher in physical education lies within being able to stimulate students who do no like physical activities or for some other reason decides not to participate. The aim of this study was to examine factors within physical education that could be the reason for students not participating and what could be done better in order to stimulate the less motivated. The study is based on interviews with ten students that went to school in two different counties. They did not consider their level of interest in sports to be influenced by their family or friends. They pointed out other factors that had been the reason for them failing Physical education. The results show that the students, mainly the girls, felt that the problem was within the corriculum, not in the syllabus. For the most part they wanted more variaty, strenght training and also a different kind of group formation. Girls also prefered more individual sports, such as different kinds of dances over too much ballgames. The students wanted the subject to teach them more about things they could benefit from in the future. The conclusion was that it would be good for the students to be divided into groups that have the same aims and interests, if possible. The teacher had a big responsibility as well as the time-schedules.

The subject of this thesis was to study two intestinal barriers to oral drug bioavailability, drug efflux proteins of the ABC-transporter family, and in particular ABCB1/P-glycoprotein (Pgp), and the drug metabolizing enzyme cytochrome P450 (CYP) 3A4. At the onset of this thesis, similarities between CYP3A4 and Pgp in terms of their tissue distribution and gene regulation, along with overlapping substrate specificities, had generated the hypothesis that CYP3A4 and Pgp may have a complementary function and thus form a coordinated intestinal barrier to drug absorption and gut wall metabolism. In the first part of this thesis, a cell culture model of the intestinal epithelium that expressed both functional Pgp and CYP3A4 was developed. This model was then used to investigate the steroselective drug efflux and metabolism of R/S-verapamil. In summary, the results indicated that the two barriers in the cell culture model were in agreement with those in the human intestine. Both ABC-transporters and CYPs are regulated by drugs that interact with nuclear receptors. However, while the regulation of CYPs is quite well understood, less is known about how repeated drug administration regulates the most abundantly expressed ABC-transporters. Therefore, in the second part of this thesis, the effects of repeated drug administration on the gene regulation of four ABC-transporters and CYP3A4 were studied in intestinal epithelial cell lines in vitro and in the perfused human jejunum in vivo. The in vitro studies revealed that the ABC-transporters are induced by drugs that interact with slightly different sets of nuclear receptors. The in vivo study showed that repeated oral administration of St John’s wort decreased the bioavailability of verapamil, predominantly by induction of intestinal CYP3A4. This part of the thesis provides new information about the regulation of ABC-transporters, shows that the intestinal metabolism is the most significant barrier to oral bioavailability of verapamil and provides evidence for a clinically significant interaction between verapamil and St John’s wort in vivo.