Serum testosterone responses to continuous and intermittent exercise training in male rats.

Serum testosterone (T) were investigated at rest and following exercise during 6 weeks of continuous and intermittent swimming training in male rats, and the regulatory mechanisms of the changes were discussed by evaluating serum luteinizing hormone (LH), and conducting GnRH (gonadotropin releasing hormone, 1.5 microg/kg body weight) or hCG (human chorionic gonadotropin, 25 IU/kg body weight) challenge tests. Relative to the resting level, serum T increased after intermittent exercise (6.47 +/- 1.58 vs 3.08 +/- 2.85 nmol/l), which was followed with the same changes in LH (12.81 +/- 4.21 vs 5.70 +/- 1.56 nmol/l). Serum T was lower after continuous exercise compared to the resting level (2.02 +/- 0.53 vs 10.96 +/- 3.11 nmol/l), while LH level was higher than that in sedentary group (11.23 +/- 5.61 vs 5.00 +/- 1.61 nmol/l). No significant changes were observed in resting T during and after intermittent training. A lower resting T level was shown at the end of 3 weeks of continuous training as compared to the sedentary group (1.88 +/- 0.69 vs 12.36 +/- 2.10 nmol/l), but it increased after 6 weeks of training. Serum T increased significantly in the intermittent training group after hCG treatment as compared to the saline treatment (52.42 +/- 12.10 vs 6.81 +/- 6.22 nmol/l), but insignificantly in the continuous training group. The similar increases in serum LH were observed in all the groups after GnRH treatment.

Comparisons of serum testosterone and corticosterone between exercise training during normoxia and hypobaric hypoxia in rats.

The purpose of this study was to compare the effects of continuous and intermittent exercise training on serum testosterone [T] and corticosterone concentrations [Cort] during normoxia and hypobaric hypoxia. Male rats swam with loads of 3% (normoxia) or 2.25% (462 mmHg) body mass for 60 min in the continuous training groups, and 15 min separated by a 7-min rest x 4, with 60-min total exercise duration in the intermittent training groups, 5 days week(-1) for 6 weeks. Serum [T] were measured at rest and following exercise after 6 weeks of training. Serum [Cort] were measured immediately after an acute period of exercise or after 6 weeks of training at rest and following exercise. Continuous exercise induced decreases in [T] under both conditions. Intermittent exercise showed a tendency to increase [T] during normoxia, but caused a suppression during hypobaric hypoxia. The [Cort] was elevated by a similar margin after an acute period of exercise during both conditions. After 6 weeks of training, however, [Cort] increased slightly after exercise during normoxia. A lower resting [Cort], which was increased after exercise, was found in the training groups during hypoxia. No relevant relationship was found between the behaviours of [T] and [Cort] after exercise during either conditions.

Tokishakuyakusan effect on DNA polymerase alpha activity in relationship to DNA synthesis before and/or after the LH/FSH surge in rats.

DNA polymerase alpha activity in ovaries of mature cycling rats during the normal estrous cycle changed in a cyclic manner with a peak at 1800 h in proestrus. Tokishakuyakusan (TS) in vivo did not affect the changes in DNA polymerase alpha and beta activities during the estrous cycle. LH and FSH at 1000 or 1700 h in proestrus increased DNA polymerase alpha activity, but the DNA polymerase alpha activity induced by LH or FSH was not significantly affected by the addition of TS. DNA polymerase beta activity did not change with LH, FSH or TS. In PMS-treated or -untreated immature rats, TS enhanced ovarian DNA polymerase alpha activity but had no significant effect on LH or FSH action. In ovaries, incubated in vitro, in untreated mature or immature rats, TS enhanced ovarian DNA polymerase alpha activity but had no significant effect on LH or FSH action. These results suggest that TS stimulates ovarian DNA polymerase alpha activity in relationship to DNA synthesis and does not affect the effect of LH or FSH on the activity by preovulatory follicle before and/or after the LH/FSH surge.

Endothelin-renin-angiotensin-atrial natriuretic peptide system in ovaries: an intraovarian ERAANP system.

In a recent investigation of the ovary, high levels of endothelin-1 (ET-1), the renin-angiotensin system (RAS), and atrial natriuretic peptide (ANP) were identified. It was determined that ET, RAS, and ANP, alone or together, affected ovarian function. It is important that mutual relationships of these vasoactive and hormonal peptides, which coexist in the ovary, are examined to determine their in vivo functions. This study, using immature rats treated with pregnant mare's serum gonadotropin (PMS), examined the effects of ET-1, angiotensin II (Ang II) and ANP, individually or in combination, on steroidogenesis by granulosa cells (GCs) cultured for 72 h. ET-1 Ang II, and ANP, alone or combined, also had a mutual effect on steroidogenesis. Concomitantly with previous findings on the ovary, the authors propose that the intraovarian endothelin-renin-angiotensin-ANP system (ERAANPS) functions as a novel intraovarian regulator system.

A proposal of ovarian ERAANPS (endothelin-renin-angiotensin-atrial natriuretic peptide system) and effects of tokishakuyakusan, keishibukuryogan, shakuyakukanzoto and unkeito on the ERAANPS.

We have previously shown the presence in a high concentration of endothelin-1 (ET) in the corpus luteum and renin-angiotensin system (RAS) and binding sites for atrial natriuretic peptide (ANP) in the ovarian follicle. The present study was undertaken to identify the existence of ET, renin, angiotensin II and the binding site for ANP in the ovary at proestrus and examine in vivo the effects of herbal medicines [Tokishakuyakusan (TS), Keishibukuryogan (KB), Shakuyakukanzoto (SK) and Unkeito (UT)] on them. ET, all components of RAS and binding sites for ANP were found at high levels in the ovary. TS, KB, SK and UT decreased the ET levels in ovary, while components of RAS and binding sites for ANP have the propensity to increase. However, ET, renin, angiotensin II and ANP levels in plasma were not at all affected before and after treatment with TS, KB, SK or UT. Taken together with previous observations showing the existence of ET, RAS and the binding site for ANP in the ovary, we propose here the ERAANPS (endothelin-renin-angiotensin-ANP system) in the ovary as a functional regulator. Further, these results suggest that TS, KB, SK or UT may regulate the ovarian ERAANPS.

Effects of tokishakuyakusan, keishibukuryogan, shakuyakukanzoto and unkeito on ovarian endothelin, renin and angiotensin II in pregnant mare's serum gonadotropin-treated immature rats.

We have previously proposed the ovarian ERAANPS (endothelin-rein- angiotensin-atrial natriuretic peptide system). The present study was undertaken to examine in vivo the effects of herbal medicines [Tokishakuyakusan (TS), Keishibukuryogan (KB), Shakuyakukanzoto (SK) and Unkeito (UT)] on endothelin-1 (ET), renin and angiotensin II (A II) in the ovaries, of immature rats treated with 10 IU PMS for 48 h. ET and all components of renin-angiotensin system (RAS) were found at high levels in the ovary. Concomitant treatment with PMS plus TS, KB, SK or UT, especially TS and UT, tended to decrease the ET levels in ovary, while components of RAS tended to increase. However, ET, renin and A II levels in plasma were not at all affected after treatment with TS, KB, SK or UT. These results suggest that TS, KB, SK or UT may regulate the ovarian ERAANPS.