OBJECTIVETo investigate the influence of fructus schisandrae (FS) on the function of the pituitary-testis axis and carbohydrate metabolism in male rats undergoing experimental navigation and strenuous exercise.

METHODSThirty-four SD rats were randomly allocated into three groups, quiescent control (A), stress control (B) and FS (C). Those in Groups B and C received 10 days of Benford's high-intensity training, followed by 7 days of intragastric administration of normal saline and FS, respectively. Blood samples were immediately obtained at the end of the experiment for the measurement of the levels of serum testosterone (T), corticosterone (CORT), luteinizing hormone (LH) and blood glucose (Glu) by radioimmunoassay. The pituitary gland and testis tissues were also collected for the observation of their ultrastructures under the electron microscope.

RESULTSGroup A showed a significantly lower Glu level and a higher T level than B ([5.22 +/- 2.13] mmol/L versus [9.41 +/- 2.56] mmol/L, and [0.61 +/- 0.68] ng/ml versus [0.10 +/- 0.15] ng/ml, P < 0.01), but there was no significant difference in the CORT level between the two groups ([4.67 +/- 1.19] ng/ml versus [7.25 +/- 6.20] ng/ml, P > 0.05). Compared with Group B, both the Glu and CORT levels were remarkably decreased in Group C ([5.09 +/- 1.64] mmol/L and [3.55 +/- 3.52] ng/ml, P < 0.05 and P < 0.01), but the T level showed no significant change ([0.11 +/- 0.12] ng/ml, P > 0.05). And there were no significant differences in the serum LH level among the three groups (P > 0.05). Ultrastructural pathology showed a significant reduction of secretory granules in the pituitary cells in Group B as compared with A, and a markedly increased number of granules in the cytoplasm in Group C in comparison with B. Such changes as mitochondrial swelling, increase of electron density and decrease or disappearance of mitochondrial cristae were also found in the Leydig cells of Group B. No significant differences were observed in the testicular cells between Groups and C.

CONCLUSIONExperimental navigation and high-intensity training significantly suppress the function of the pituitary-testis axis in rats. Intragastric administration of fructus schisandrae can protect the pituitary-testis axis and reduce the blood Glu level in the stressed rats.