Abstract: OBJECTIVE:To study the development mechanism of kidney-Yang deficiency through the establishment of support vector machine models of relevant hormones of the pituitary-target gland axes in rats with kidney-Yang deficiency syndrome.METHODS:The kidney-Yang deficiency rat model was created by intramuscular injection of hydrocortisone,and contents of the hormones of the pituita- ry-thyroid axis:thyroid stimulating hormone(TSH),3,3',5-triiodothyronine(T_3) and thyroxine(T_4);hormones of the pituitary-adrenal gland axis:adrenocorticotropic hormone(ACTH) and Cortisol(CORT);and hormones of the pituitary-gonadal axis:luteinizing hormone(LH),follicle-stimulating hormone(FSH),and testosterone(T),were determined in the early,middle,and advanced stages.Ten support vector regression(SVR) models of the hormones were established to analyze the mutual relationships among the hormones of the three axes.RESULTS:The feedback control action of the pituitary-adrenal axis began to lose efficacy from the middle stage of kidney-Kong deficiency.The contents all hormones of the three pituitary-target gland axes decreased in the advanced stage.Relative errors of the jackknife test of the SVR models all were less than 10%.CONCLUSION:Imbalances in mutual regulation among the hormones of the pituitary-target gland axes,especially loss of effectiveness of the pituitary-adrenal axis,is one pathogenesis of kidney-Yang deficiency.The SVR model can accurately reflect the complicated non-linear relationships among pituitary-target gland axes in rats with of kidney-Yang deficiency.

Key words: Kidney Yang deficiency, Support vector regression machine, Pituitary-thyroid axis, Pituitary-adrenal axis, Pituitary-gonadal axis