The objective of our study was: (1) to compare the influence of moderate exercise on circulatory afterresponse in mildly hypertensive (n = 8) and normotensive male subjects (n = 9); (2) to examine the circulatory response to 3-min hyperoxic inactivation of arterial chemoreceptors at rest and during postexercise period in both groups. Hypertensive men (HTS) with a systolic blood pressure (SBP) 148 ؎ 5 mm Hg, diastolic blood pressure (DBP) 92.4 ؎ 4 mm Hg; and normotensive men (NTS), with a SBP 126 ؎ 3 mm Hg, DBP 75.6 ؎ 1.3 mm Hg, were submitted to 20-min of moderate exercise on a cycloergometer (up to the level of 55% of each subject's resting heart rate reserve). Finger arterial BP was recorded continuously with Finapres, impedance reography was used for recording stroke volume, cardiac output and arm blood flow. In HTS a significant decrease in SBP by 14.5 ؎ 3.4 mm Hg, DBP by 8.9 ؎ 1.9

testi s as a control (6-OHDA experiments ). Animals were weaned on day 25, and were sacrificed between days 42 and 70: After the testes had been weighed, they were fixed with Bouin's solution, embedded in paraffin, sliced and Stained with hematoxylin and eosin for histological examination. Statistical analysis was performed by the t-test.Results and discussion. The table shows the testicular weights and the incidence of growth retardation. Denervation caused a significant reduction in the right testicular weight a s compared to th e left except in the group operated on the 21st day of life. The incidence of rats with a righttestis weight which was less than 75% of the left testicular weight decreased with inCreasing age at the time of operation. From the gradual reduction in the incidence from 100% (operatio n at day 13) to 43% (operation at day 21), it may be speculated that there might be a critical time period up to the age of 15 days for the nervous system in promoting testicular growth. After the rats are 15 days 01d, the neural effect may be overridden by hormonal activities, since g0nadotropins and testosterone levels in blood dramatically increase during days 15-20 after birth8,9. 9 6-OHDA, which destroys sympathetic nerve terminals, was injected into the right testis. This local chemical sympathectomy retarted testicular growth in treated rats (B l-B6), and there was also a gradual reduction in the incidence at the 75% criteria level. No compensatory hypertrophy Was observed in the untreated (left) testes up to at least 42 days after birth in the operated group (A3, B1-B5); i.e., the weights of the left testes of the operated rats did not differ from those in control animals. Photographs of the histological preparations of the denervated or 6-OHDA-treated testes are shown in the figure. Seminiferous epithelial cells of denervated testes were degenerated and reduced, some portions of the seminiferous tubules were destroyed, digest-Experientia 38 (1982), Birkh~user Verlag, CH-4010 Basel/Switzerland