Analysis of the regulation of basal metabolism in dependence on environmental factors and body weight

Abstract

Analysis of the regulation of basal metabolism in dependence on environmental factors and body weight. In large-scale experiments carried out over a period of about 15 years, white rats were subjected to chronic treatment with antithyroid drugs, substances counteracting LANGERHANS' islets (mostly alloxan), hormone fragments, and native hormones respectively. The O~-consumption (mostly in an artificial microclimate) was measured in each test. The test batches were either gradually diminished by killing the animals one after another, to yield histological series in chronological order, or a whole batch was pooled together at the end of a test. In all experiments a relationship could be established between O2-consumption and the histology" "(histochemical tests included) of liver and endocrine glands. In a recent experiment, moreover, serum enzymes and the level of blood sugar were determined; a chromatographic analysis of thyroid hormone fractions and blood cells-counts were made. Combining these methods led to numerous variables suitable for numerical treatment. Besides a treatment of the data by elementary methods (variance analysis, t-test, U-test, linear 2-dimensional regression analysis), multidimensional space models, employing traditional and novel calculi were used. The regression equations in 23-dimensional statements were linear, quadratic and cubic. In a concordance analysis 25 variables were carried along. To develop a satisfactory theory, the coefficients of the differential equations underlying the material were determined by means of an approximation method suited for random samples subject to variance. For solution, integrals, polynomials of e-functions, using mostly the regression calculus in two steps were sought. The oscillations caused by environmental factors were extracted as the differences between the function values of the optimal particular and real integral and the empirical ordinates. This isolated swinging remainder was analysed following FouriEr. The spectra or the oscillation portions themselves were brought into functional relation with one another by means of functional operators always controlled by hetero-and auto-correlation. The model of the control of metaboIism by the diencephalicpituitary-thyroid-system could thus be reduced to an n-dimensional linear space model, which, however, is not quite satisfactory.