This paper presents a narrative summary of an increasingly important trend in medical education by addressing the merits of community-based distributive medical education (CBDME). This is a relatively new and compelling model for teaching and training physicians in a manner that may better meet societal needs and expectations. Issues and trends regarding the growing shortage and imbalanced distribution of physicians in the USA are addressed, including the role of international medical graduates. A historical overview of costs and funding sources for medical education is presented, as well as initiatives to increase the training and placement of physicians cost-effectively through new and expanded medical schools, two- and four-year regional or branch campuses and CBDME. Our research confirms that although medical schools have responded to Association of American Medical Colleges calls for higher student enrollment and societal concerns about the distribution and placement of physicians, significant opportunities for improvement remain. Finally, the authors recommend further research be conducted to guide policy on incentives for physicians to locate in underserved communities, and determine the cost-effectiveness of the CBDME model in both the near and long terms.

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Adenosine 3'5'-cyclic phosphate stimulated the conversion of added cholesterol to pregnenolone in "coupled" rat adrenal mitochondria provided with succinate, and in "leaky" mitochondria fortified with reduced nicotinamide adenine dinucleotide phosphate. Adenine nucleotides other than adenosine 3',5'-cyclic phosphate did not duplicate these actions. The cyclic nucleotide was also effective in supernatants from sonically disrupted mitochondria. The minimum effective concentration was 50 micromoles per liter or less. The results suggest that adenosine 3',5'-cyclic phosphate stimulates corticosteroidogenesis by activating the mitochondrial enzymes which are rate-limiting in the utilization of cholesterol.

The reactions which result in the conversion of pregnenolone to progesterone and of progesterone to deoxycorticosterone in undisrupted microsomal preparations from rat adrenal glands were stimulated by homologous serum. The active materials were shown to be firmly associated with serum proteins. The dialysable fraction of serum was either without effect on these transformations or was inhibitory. The enzyme systems involved were partially solubilized by exposure of the microsomal preparation to prolonged sonic treatment or to 1% Triton N-101. After either treatment, 35-40% of the original specific activity of the steroid 21-hydroxylase system responsible for the conversion of progesterone to deoxycorticosterone was found in the supernatant fraction after high-speed centrifuga-J Reprint requests to S. R. hydroxysteroid dehydrogenase activity, but did not activate 5-ene-3oxosteroid isomerase in the microsomal fraction. This finding suggested that activation of 5-ene-3/?-hydroxysteroid dehydrogenase was responsible for stimulation of progesterone synthesis from pregnenolone. The results indicate that the protein-bound factor in rat serum which was capable of stimulating the conversion of progesterone to deoxycorticosterone in microsomal preparations from rat adrenal glands was different from that which activates the conversion of pregnenolone to progesterone. Moreover, these diverse factors appeared to act by different mechanisms.-60°C. The frozen