飞行训练对飞行学员下丘脑-垂体-性腺轴功能的影响

目的 探讨飞行训练对飞行学员下丘脑－垂体－性腺轴功能的影响。方法 采用放射免疫法检测飞行基础学校毕业学员（１４０名）和飞行学院完成初教机（８２名）、高教机（２９名）训练阶段的学员的血清雌二醇、睾酮、催乳素、卵泡刺激素和黄体生成素５项指标。选择２０名场站地面战士作为对照组。结果 ①各学员组雌二醇、睾酮、催乳素、黄体生成素、卵泡刺激素和雌二醇／睾酮比值较对照组有不同程度改变;②其中尤以雌二醇、睾酮和雌二醇／睾酮比值改变明显;③各学员组自身比较结果显示,随着飞行时间的延长和训练强度的增大,飞行学员性激素水平的变化较大。结论 飞行训练对飞行学员下丘脑－垂体－性腺轴性激素分泌水平有一定影响,飞行因素引起的性激素失衡可能与飞行人员常见病的发生相关。     

Circadian rhythm of plasma levels of lipids, carbohydrates and various hormones in healthy pilots

Circadian variations of plasma lipids (cholesterol, total lipids, triglycerides, beta-lipoproteins), sugars and selected hormones (cortisol, testosterone, estradiol, aldosterone) were measured in 30 healthy pilots, aged 30-39 years. The control group consisted of 15 healthy nonpilots of similar age. Experimental data were statistically treated using cosinor analysis. In contrast to the ground-based personnel, the pilots showed in increase in the average daily content of lipids and hormones, a decrease in the average daily content of sugar, and an increase in the amplitude of cholesterol, triglycerides, total lipids, beta-lipoproteins, cortisol, testosterone and aldosterone. Estradiol rhythms were very similar in both groups. Acrophases of triglycerides, testosterone and estradiol were almost synchronized. Acrophases of other parameters were different in values which were greater than the acrophase drift range. The specific features of circadian rhythms of plasma lipids, carbohydrates and hormones seem to reflect the specific features of professional activities of pilots. The above investigations of circadian variations of plasma lipids, carbohydrates and hormones in healthy pilots represent the first attempt of recording circadian parameters of their biochemical substrates.     

Endocrine responses to marathon running.

We have examined the hormone status of ten healthy adult males who completed the Glasgow marathon. Serum thyroxine, free thyroxine, triiodothyronine and thyroid stimulating hormone were unaffected by the exertion. Serum cortisol as well as other steroid hormones, androstenedione, dehydroepiandrosterone sulphate and oestradiol showed distinct rises (p less than 0.01) but serum testosterone fell significantly (p less than 0.01). There was no change in sex hormone binding globulin capacity but a significant fall in LH levels (p less than 0.05) accompanied the fall in serum testosterone. The mechanism of the fall in serum testosterone in this situation requires clarification but it is unlikely to have adverse consequences.     

绝经后妇女原发性高血压患者性激素变化及胰岛素抵抗的关系

目的：探讨绝经后妇女原发性高血压（EH）患者性激素水平变化及与胰岛素抵抗的关系。方法：对33例绝经1年以上妇女原发性高血压患者（A组）,21例绝经1年以上无高血压健康妇女（B组）的血清雌二醇（E2）,孕酮（P）,睾酮（T）,血浆葡萄糖（G）,血浆胰岛素（INS）及胰岛素敏感指数（ISI）进行检测。结果：A组E2水平较B组明显降低,P水平显著增高,相关分析发现,E2与INS呈显著负相关,而E2与ISI呈显著正相关,P与INS呈显著正相关,与ISI呈显著负相关。结论：绝经后妇女原发性高血压患者存在严重的性激素失调,且与胰岛素抵抗并存,可能参与绝经后妇女原发性高血压的发生和发展。     

不同飞行条件下飞行员血清催乳素、雌二醇、醛固酮的变化

目的探讨不同飞行应激条件下飞行员血清催乳素、雌二醇、醛固酮水平的变化。方法应用放射免疫分析法,对40名飞行员按不同分组检测飞行训练前后血清催乳素、雌二醇、醛固酮水平,并进行对比分析。结果不同飞行时间、不同飞行场次、不同飞行载荷、不同飞行高度飞行后血清雌二醇水平分别为(137.98±15.89)pg/mL和(134.52±13.17)pg/mL、(131.59±17.45)pg/mL和(119.83±19.45)pg/mL、(132.26±14.90)pg/mL和(122.57±17.41)pg/mL、(126.67±14.85)pg/mL和(121.53±19.92)pg/mL,与飞行前比较差异有统计学意义(P<0.01和P<0.05);血清催乳素、醛固酮水平飞行前后比较差异无统计学意义(P>0.05)。结论在不同飞行应激条件下,战斗机飞行员飞行训练后血清雌二醇水平降低,血清催乳素、醛固酮水平无变化。     

绝经后妇女原发性高血压患者性激素变化与胰岛素抵抗的关系

目的　探讨绝经后妇女原发性高血压 (EH)患者性激素水平变化及与胰岛素抵抗的关系。方法　对 3 3例绝经 1年以上妇女原发性高血压患者 (A组 )、2 1例绝经 1年以上无高血压健康妇女 (B组 )的血清雌二醇 (E2 )、孕酮 (P)、睾酮(T)、血浆葡萄糖 (G)、血浆胰岛素 (INS)及胰岛素敏感指数 (ISI)进行检测。结果　A组E2 水平较B组明显降低 ,P水平显著增高。相关分析发现 ,E2 与INS呈显著负相关 ,而E2 与ISI呈显著正相关 ;P与INS呈显著正相关 ,与ISI呈显著负相关。结论　绝经后妇女原发性高血压患者存在严重的性激素失调 ,且与胰岛素抵抗并存 ,可能参与绝经后妇女原发性高血压的发生和发展。     

健康老年男性脂肪负荷餐后雄激素水平的改变

 目的探讨健康老年男性富含三酰甘油脂蛋白(TRL)清除延迟与性激素水平改变的关系.方法与脂肪耐量试验同时采集空腹、脂肪负荷餐后(餐后)3 h、8 h静脉血.测定血浆三酰甘油(TG)、高密度脂蛋白-胆固醇(HDL-C)、总胆固醇(CHO)和血浆睾酮(T)、雌二醇(E2)、垂体泌乳素(PRL)、促黄体生成激素(LH)、促卵泡激素(FSH)动态变化水平.结果健康老年男性TRL清除延迟发生率7.8%.TRL清除延迟组较清除正常组基础T水平低、E2水平相对高(P＜0.01或P＜0.05).餐后高TG应答和(或)TRL清除延迟导致血浆T水平降低、E2水平升高(P＜0.01或P＜0.05),T/E2比值失衡.血浆PRL、LH、FSH改变差异无统计学意义(P＞0.05).结论 TRL清除延迟是致动脉粥样硬化的危险因素,也是导致健康老年男性T/E2比值失衡的直接原因,可能与动脉粥样硬化发生发展有关.     

Flight influence on the plasma level of renin-angiotensin-aldosterone system and atrial natriuretic peptide

Plasma levels of the renin-angiotensin-aldosterone system (RAAS) and atrial natriuretic peptide (ANP) were studied in healthy male pilots, and in a ground crew control group. Plasma concentrations of angiotensin I (A I), angiotensin II (A II) and aldosterone (Aldo) were measured in the pilots before and after flight by radioimmunoassay. Results showed that the plasma concentrations of A I, A II, and Aldo were much higher after flight than before flight, and were different from samples taken from the control group (p less than 0.001). On the other hand, the ANP levels in the pilot group did not differ significantly from the control group, before or after flight. There was no significant difference of the four hormones within the control group over the course of the study. This suggests that the development of hypertension in pilots may relate to the reaction of the RAAS.     

Simulator induced syndrome: evidence for long-term aftereffects

Pilots have experienced various adverse symptoms hours and even days following flight simulator training. This study surveyed pilots undergoing simulator training in an attempt to provide an initial gauge of the extent, severity, and possible risk factors of long-term (greater than 1 day) simulator aftereffects. A three-part voluntary and anonymous questionnaire was used to gather data. We studied pilots of varying experience undergoing advanced flight training which included the use of flight simulators. Some 238 pilots participated in the study, and 196 completed the follow-up survey concerning long-term effects. Nine (4.6%) pilots experienced adverse symptoms 24 h or more after completion of their last simulator training, which they attributed to their recent simulator experience. Symptoms reported included: recurrent visual flashbacks, continued balance disturbance, and hand-eye discoordination. Three pilots (1.5%) reported difficulties flying aircraft. Pilot flight experience level, total simulator time, length of simulator session, and sex were not predictive of risk. This study suggests that long-term (greater than 1 day) adverse aftereffects may occur following simulator training.     

Thoracolumbar pain among fighter pilots.

High +Gz forces place high stress on the spinal column, and fighter pilots flying high-performance fighter aircraft frequently] report work-related thoracic and lumbar spine pain. The aim of this study was to determine whether +Gz exposure causes work-related thoracolumbar spine pain among fighter pilots. A questionnaire was used to establish the occurrence of thoracic and lumbar spine pain during the preceding 12 months and during duties over the whole working career among 320 fighter pilots and 283 nonflying controls matched for age and sex. Thirty-two percent of the pilots and 19% of the controls had experienced pain in the thoracic spine during the preceding 12 months (odds ratio [OR] = 2.3; 95% confidence interval [CI] = 1.5-3.5; p = 0.002 for the pilots). Among the pilots, the OR increased up to 6.1 (95% CI = 1.6-23.1; p = 0.0007) with the number of +Gz flight hours. There was no difference between the groups with regard to lumbar pain during the preceding 12 months, but over their whole working careers fighter pilots (58%) had experienced lumbar pain during their duties more often than controls (48%) (OR = 1.8; 95% CI = 1.3-2.6; p = 0.002). The greater the number of +Gz flight hours, the greater the occurrence of lumbar spine pain when on duty (OR = 26.9; 95% CI = 6.2-116; p = 0.0001 for the most experienced fighter pilots). The same was not true with regard to the number of +Gz flight hours and lumbar pain during the preceding 12 months. Age had no effect on pain in the thoracic or lumbar spine. Fighter pilots flying high-performance aircraft have more work-related thoracic and lumbar spine pain than controls of the same age and sex. The difference is explained by the pilots' exposure to +Gz forces.     

Acute hormonal responses in elite junior weightlifters.

To date, no published studies have demonstrated resistance exercise-induced increases in serum testosterone in adolescent males. Furthermore, few data are available on the effects of training experience and lifting performance on acute hormonal responses to weightlifting in young males. Twenty-eight junior elite male Olympic-style weightlifters (17.3 +/- 1.4 yrs) volunteered for the study. An acute weightlifting exercise protocol using moderate to high intensity loads and low volume, characteristic of many weightlifting training sessions, was examined. The exercise protocol was directed toward the training associated with the snatch lift weightlifting exercise. Blood samples were obtained from a superficial arm vein at 7 a.m. (for baseline measurements), and again at pre-exercise, 5 min post-, and 15 min post-exercise time points for determination of serum testosterone, cortisol, growth hormone, plasma beta-endorphin, and whole blood lactate. The exercise protocol elicited significant (p less than or equal to 0.05) increases in each of the hormones and whole blood lactate compared to pre-exercise measures. While not being significantly older, subsequent analysis revealed that subjects with greater than 2 years training experience exhibited significant exercise-induced increases in serum testosterone from pre-exercise to 5 min post-exercise (16.2 +/- 6.2 to 21.4 +/- 7.9 nmol.l-1), while those with less than or equal to 2 years training showed no significant serum testosterone differences. None of the other hormones or whole blood lactate appear to be influenced by training experience.(ABSTRACT TRUNCATED AT 250 WORDS)     

Reproductive hormonal profiles of endurance-trained and untrained males

This study compares the resting reproductive hormonal profiles of untrained (N = 11) and endurance-trained (N = 11) males. Testosterone, free testosterone, estradiol, luteinizing hormone (LH), prolactin, and cortisol were measured by radioimmunoassay in resting blood samples (8 h fast) collected every 60 min for 4 h. The endurance-trained group had been active for (mean +/- SE) 12.4 +/- 6.7 yr, 6.6 +/- 0.2 d.wk-1, 68.5 +/- 4.4 min.d-1, while the untrained group was sedentary. Neither group had histories of hypothalamic-pituitary-testicular disorders. The overall 4 h mean testosterone and free testosterone levels were significantly (P less than 0.05) lower in the trained group (4.99 +/- 0.46 vs 7.25 +/- 0.67 ng.ml-1, and 17.2 +/- 1.4 vs 23.6 +/- 0.6 pg.ml-1, for the trained and untrained groups, respectively). The LH of the endurance-trained group was higher (15.3 +/- 1.9 vs 11.7 +/- 1.2 mIU.ml-1, P = 0.06); however, LH pulse frequency and amplitude did not differ between groups. An enhanced estradiol feedback to the hypothalamus-pituitary could not account for the elevated LH, as estradiol levels were similar in the groups. Prolactin and cortisol levels were normal and did not differ between groups. The results suggested normal hypothalamic-pituitary function existed in the trained subjects, and prolactin and cortisol were not causative factors in the lowered resting testosterone and free testosterone levels. The findings indicate that chronic endurance training lowers testosterone and free testosterone in males possibly by impairing testicular function.     

高+G_z应激对高性能战斗机飞行员尿中睾酮、皮质醇和醛固酮含量的影响

目的 探讨高+G_z应激对高性能战斗机飞行员尿中睾酮(T)、皮质醇(C)和醛固酮(Ald)含量的影响,为飞行员身体机能评价提供依据.方法 56名高性能战斗机飞行员,收集离心机训练(+7.0 G_z或+8.0 G_z)前、后的尿标本,分别检测尿中T、C和Ald含量,对不同时间的尿标本检测结果进行统计学处理.结果 高+G_z暴露后飞行员尿中T含量、Ald含量和尿中T/C比值明显降低,尿中C含量明显升高,其结果与暴露前比较差异有统计学意义(t=4.658、2.139、2.086、2.262,P<0.05或P<0.01).结论 高+G_z应激对高性能战斗机飞行员尿中T、C和Ald含量影响显著.尿中T和C含量与血清T和C水平之间有一致性变化,应进一步研究将尿液激素含量检测作为飞行员机能评价手段的可行性.     

Neuromuscular adaptations and serum hormones in females during prolonged power training

Training-induced adaptations in the neuromuscular and endocrine systems were investigated in seven females during prolonged power type strength training. Great (p less than 0.05) changes occurred primarily during the earlier weeks of the 16-week training especially in the time of force production (from 161 +/- 107 to 93 +/- 65 ms to produce a 500 N force) and, correspondingly, in the average forces in the earlier positions of the (absolute) force-time curve of the leg extensor muscles. These changes were accompanied by significant (p less than 0.05) increases in the neural activation of the trained muscles in the earliest positions of the IEMG-time curve. Hypertrophic changes, as judged from muscle fibre area data of both FT and ST types, were only slight (ns.) during the entire training period. No statistically significant changes occurred during the training in mean concentrations of serum testosterone, free testosterone, follicle stimulating hormone (FSH), luteinizing hormone (LH), cortisol, progesterone, estradiol (E2) or sex hormone-binding globulin (SHBG). However, the individual mean serum levels of both total and free testosterone correlated significantly (r = .81-.95, p less than 0.05-0.01) with the individual changes during the training in the time of force production and in the forces in the force-time curve of the trained muscles. The present results in female subjects indicate the important role of training-induced adaptations in the nervous system for muscular power development. In females testosterone may be of great importance for muscular power and/or strength development during prolonged training and an important indicator of the trainability of an individual.     

Simulator induced syndrome in Coast Guard aviators

The incidence of adverse symptoms in Coast Guard aviators undergoing flight simulator training was determined. A voluntary, multi-part questionnaire was completed by 238 pilots. During the first simulator flight 64.3% of pilots reported at least one adverse symptom, 39.4% during the last flight. Simulator induced syndrome (SIS) was present in 47.1% of subjects during the first simulator flight, 23.5% during their last flight. Most subjects reported their symptoms as mild, with some symptoms rated as moderate or severe in nature. There was no statistically significant association (p greater than 0.05) between the development of SIS and flight experience, simulator experience, length of simulator session, or self-determined motion sickness susceptibility. There was a significant association (p less than 0.05) between SIS development and the use of simulators with computer-generated imagery (CGI). Nine pilots experienced adverse symptoms at least 2 d after their last simulator flight. In conclusion, this study revealed that SIS occurs frequently, is more common when CGI is present, may recur, suggests an adaptative process, and may not be associated with some factors previously claimed.     

Neuroendocrine responses to psychological workload of instrument flying in student pilots.

BACKGROUND: Information processing and stress tolerance are necessary features for instrument flying (IFR), especially among student pilots. Psychological workload of IFR flight may lead to stress reactions such as neuroendocrine activity. METHODS: Neuroendocrine responses to an IFR flight with Vinka piston-engined primary trainer were studied in 35 male volunteers who participated in the basic military flying course of the Finnish Air Force (FAF). The student pilots performed a 40-min IFR flight mission and a control session on land in randomized order between 11.00 h and 15.00 h. The IFR flight included 3 NDB approaches and was evaluated by flight instructors. Blood samples were collected 15 min before, 5 min and 60 min after the flight as well as control session, and. Plasma ACTH, beta3-endorphin (BE), cortisol, prolactin, adrenaline (A) and noradrenaline (NA) were measured. Psychological evaluations included psychomotor test (Wiener), Multi Coordination and Attention Test, ability tests and personality tests (CMPS and 16 PF). The overall psychological evaluation was made by an aviation psychologist. RESULTS: Plasma ACTH was significantly higher before and 5 min after the flight compared with control levels, but plasma BE increased significantly only before the flight. Plasma cortisol was significantly elevated before and 5 min after the flight. Plasma prolactin, NA and A increases were significant 5 min after the flight. High A levels after the flight correlated significantly with poor IFR flight performance as well as with poor psychomotor test results. CONCLUSIONS: The plasma prolactin and NA increases after the flight represented a direct type of stress reaction to the flight situation. The plasma BE response to IFR flight was an anticipatory stress reaction, but plasma ACTH, cortisol and A responses included both anticipatory and direct types of stress reactions. Psychological factors, flight performance and neuroendocrine responses to IFR flight appear to be associated with each other. Therefore, neuroendocrine reactions as a response to the psychological workload of military flying could be used for identifying stress tolerance in military pilots.     

Hormonal changes after parabolic flight: implications on the development of motion sickness

Twenty-two different humoral parameters including stress-, gastrointestinal- and volume-regulating hormones were measured before and within 45 min after parabolic flight maneuvers of twenty healthy adult subjects. We compared hormonal data of motion sickness-affected participants with those unaffected. Changes in cortisol and vasoactive intestinal peptide plasma levels were significantly different (p less than 0.002 and p less than 0.004) between the two groups with increasing plasma levels of both hormones during motion sickness but decreasing levels within the control group. Growth hormone and prolactin plasma levels increased by 400% and 115% within the motion sickness-affected group and to a smaller degree (120% and 40% increases, respectively) within the control group, while ACTH levels were almost unchanged within both groups. Pancreatic polypeptide and gastrin plasma levels as well as plasma levels of insulin and C-peptide were significantly decreased within both groups after the parabolic flight. Plasma renin, aldosterone, atrial natriuretic peptide and cyclic GMP levels were unchanged within the control group. Within the motion sickness-affected group, plasma renin and aldosterone levels were decreased and atrial natriuretic peptide levels increased after the flight. Humoral parameters of the thyroid gland were neither changed within the groups nor different between the groups. The present data confirm previous results that increases in plasma levels of certain stress hormones participate in motion sickness. Furthermore, increases in vasoactive intestinal peptide levels participate in motion sickness. These increases could explain some of the gastrointestinal symptoms in motion sickness and might serve as markers for a discrimination between regular stress and motion sickness.     

Serum estradiol, progesterone, testosterone, FSH and LH levels in postmenopausal women with Alzheimer's dementia

Several studies have suggested that estrogen replacement therapy lowers the risk of Alzheimer's dementia (AD) among postmenopausal women. Other studies have evaluated serum levels of sex hormones and gonadotropins in women with AD. Estrogens (E(1) and E(2)), luteinizing hormone (LH) and follicular stimulating hormone (FSH), dihydroepiandrosterone and sex hormone binding albumin, which normally responds to circulating testosterone, have been investigated by others using the same protocol in postmenopausal women with AD, older than 65 years. Others have studied in elderly women with AD, also using one protocol, fewer sex hormones and/or gonadotropins. We have studied the serum levels of estradiol, progesterone, testosterone, LH and FSH in the same serum sample of postmenopausal women with AD and other dementias and compared them to a group of controls. We are not aware of a similar study in the literature. All patients were diagnosed on clinical grounds and screened by the mini mental score examination (MMSE). Forty eight women had AD (Group A), mean age 72 years and age range 60-84 years, s even had other types of dementia (Group B), mean age 63.5 years and age range 53-74 years and 33 women had no cognitive impairment and were studied as controls (Group C). Group C women had mean age of 65 years and their age ranged between 55-73 years. Estradiol, progesterone and testosterone were measured by radioimmunoassay (RIA), while FSH and LH by radioimmunometric assay (IRMA). Our results showed that estradiol was significantly lower in Group A as compared to Group C (P=0.04). There was no significant difference in the levels of the other four hormones in the three Groups as studied by the Mann-Whitney U and the Pearson's statistical test. Our results were not influenced by differences due to sex, age, ethnic group or education since these factors were either similar or comparable in all Groups studied. All but two of the subjects, with mild alcoholism, smoking, increased BMI and chronic diseases, had all five hormones studied within reference limits. We consider that the absence of difference we found in the four hormone levels, in Groups A, B and C may be related to free hormones, to the different stage of AD of our patients, to intra assay variability, to assay sensitivity or to other non specified factors. Future study may be directed towards whether a primary or secondary hypogonadism exists in AD and whether hormones are contributing to or are the result of brain degeneration in AD.     

特技飞行对心钠素、环核苷酸及血管紧张素Ⅱ的影响

用放射免疫法测定了16名飞行员复杂特技飞行前后的血浆心钠素(ANF)、环磷酸鸟苷(cGMP)、环磷酸腺苷(cAMP)以及血管紧张素II(ATII)含量,并以16名地勤人员作对照结果发现,飞行前空地勤人员血浆ANF、cGMP、cAMP及ATII含量均无明显差异(P>0.05).特技飞行后立即,飞行组血浆ANF、cGMP及cAMP明显增高,与对照组相比,差异十分显著(P<0.001),但血浆ATII水平未见明显变化(P>0.05).至特技飞行后6h,飞行组血浆ANF含量已恢复至正常(P>0.05),但cGMP及cAMP仍维持在较高水平,与对照组相比,差异仍较显著(P相似文献   

Effects of a diet regimen on pituitary and steroid hormones in male ice hockey players.

Serum concentrations of androgens, cortisol, androgen binding proteins, pituitary hormones, together with anthropometric variables and sports performance were studied in two different elite male ice hockey teams. One of the teams (DIF, n = 22) participated in a special dietary program including reduction in fat from approximately 40 per cent of total energy intake (E%) to less than 30 E% and an increase in carbohydrate intake from 45 E% to about 55 E%, while the other (SSK, n = 21) served as a control group and had no special dietary program. The study covered a 7-month period. Basal values of serum testosterone, sex hormone binding globulin (SHBG), non-SHBG-bound testosterone (NST), cortisol, dehydroepiandrosterone sulfate (DHAS) and LH did not differ between the two teams. Serum concentrations of testosterone, SHBG, NST and cortisol increased significantly during the study period in the DIF group and were, with the exception of SHBG, significantly higher than in the SSK group at the end of the study (33.0 vs 26.8 nmol/l, p less than 0.05; 22.5 vs 18.3 nmol/l, p less than 0.05; and 548 vs 464 nmol/l, p less than 0.01). The ratio between NST and cortisol which was used as an index of anabolic/catabolic steroid balance did not change in either group during the study. A significant decrease in the serum concentrations of LH during the observation period was found in the SSK group. The endocrine differences between the teams may be explained by a relative negative energy balance in DIF, together with a reduced fat and increased carbohydrate intake.(ABSTRACT TRUNCATED AT 250 WORDS)