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Objective: To study the aging male rats reduced androgens and metabolic relationship between the mechanism of androgen to reduce the occurrence, especially in Leydig cell number, morphology and secretory function changes. Methods: take nine months (young) and 12,15,18,21-month-old (middle-aged) male SD rats 6 month age group, blood testing Metabolic indicators of change, including high-density lipoprotein (high density lipoprotein, HDL), LDL (low density lipoprotein, LDL), triglycerides (triglyceride, TG), total cholesterol (total cholesterol, TC), glucose (glucose, Glu), insulin (insulin, INS ), glucagon (immunoreactive glucagon, IRG), leptin (Leptin, LP) content; detection of serum hormone changes, including total testosterone (total Testosterone, tT), luteinizing hormone (luteinizing hormone, LH), follicle stimulating hormone (follicle-stimulating hormone, FSH); through tissue slices of rat Leydig cell morphological changes; using human chorionic gonadotropin (human chorionic gonadotrophin, hCG), forskolin (Forskolin) stimulated in vitro rat Leydig cells, relatively medium concentration of testosterone; using deoxynucleotidyl transferase-mediated dUTP nick end labeling (deoxynucleotidyl transferase mediated dUTP nick end labeling assay, TUNEL) testing methods rat Leydig cells apoptosis; separation weighing visceral fat, visceral fat calculation / body weight ratio and Lee's index. Results: The serum of aged rats tT [(1.26 ± 0.65) ng / ml] than young rats [(3.24 ± 0.38) ng / ml] was significantly lower (P lt; 0.01); testosterone secretion in aged rats Index ( testosterone secretion index, TSI) [(0.07 ± 0.05) ng / mIU] than young rats [(0.21 ± 0.01) ng / mIU] decreased significantly (P lt; 0.01); different age rat Leydig cell morphology have more significant differences; aged rats in vitro Leydig cells was significantly decreased (P lt; 0.05); in aged rats Leydig cells of TUNEL-positive rate (17.36% ± 1.31%) than young rats (7.02% ± 1.05%) was significantly higher (P lt; 0.01); groups and youth groups in aging rats IRG, HDL, LDL, TG, TC and visceral fat were significantly different (P lt; 0.05). Conclusion: Serum tT aged rats were significantly lower than young rats, metabolic parameters with lower serum tT Occurrence changed; androgen in aged rats may be associated with reduced Leydig cell function decline, reducing the number of mesenchymal cells and pituitary related functional decline.
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