Influence of physical training,aortic constriction and exogenous anterior pituitary hormones on the heart weights of hypophysectomized rats

Summary Studies were conducted with hypophysectomized rats to determine the effects of chronic exercise (training), injections of exogenous hormones, aortic constrictions and combinations there of on the weight of the heart. In addition, the role of growth hormone on cardiac weight was reinvestigated. The hypophysectomized rats that were trained for 10 weeks or longer had significantly heavier heart weights than their nontrained counterparts. When daily injections of a single exogenous hormone of ACTH, GH, ICSH or TSH were made into trained and nontrained animals, there was no trained group that had significantly heavier heart weights than their control group. Rats having aortic constrictions or receiving DOCA injections also had significantly heavier heart weights than their controls. When various dosages of GH (0.2 mg to 6.0 mg) were injected daily for three weeks, no evidence was obtained that indicated that the presence of this hormone resulted in cardiac enlargement. It was concluded that under the experimental condition of this study, cardiac enlargement can occur in hypophysectomized rats when the work demands on the heart have been increased.Supported in part by funds provided by the Iowa Heart Association.     

The endoproteolytic maturation of progastrin and procholecystokinin

The homologous brain-gut propeptides, procholecystokinin (proCCK) and progastrin, both undergo extensive posttranslational maturation in specific neuroendocrine cells. The process comprises multiple endoproteolytic cleavages at mono- and dibasic sites, in addition to exoproteolytic trimmings and amino acid derivatizations. Knockout of prohormone convertases (PCs) in mice and studies in cell lines indicate that PC1, PC2 and, to a minor extent, PC5, are responsible for most of the endoproteolytic cleavages of both prohormones. Progastrin in antral G-cells is cleaved by PC1 at two di-Arg sites, R36R37 and R73R74, whereas, PC2 only cleaves at the single di-Lys site, K53K54. Pituitary corticotrophs and intestinal TG-cells, both of which express gastrin, do not cleave K53K54 due to lack of PC2. In proCCK five monobasic (R25, R44, R50, K61 and R75) as well as a single dibasic site (R85R86) can all be cleaved by both PC1 and PC2. But the cleavage differs in a cell-specific manner in that PC1 is responsible for the entire endoproteolytic cleavage in intestinal endocrine I-cells, except for perhaps the K61 site. In contrast PC2 is responsible for most endoproteolysis of proCCK in the cerebral CCK-neurons, which do not express PC1 in significant amounts. Moreover, PC5 appears to contribute to a minor extent to the neuronal proCCK and to the antral progastrin processing. This review emphasizes that prohormone convertases play a decisive but substrate and cell-specific role in the biosynthetic maturation of gastrin and CCK.     

Metabolic,body temperature and hormonal responses to repeated periods of prolonged cycle-ergometer exercise in men

Summary This study was designed to find out whether rest intervals and prevention of dehydration during prolonged exercise inhibit a drift in metabolic rate, body temperature and hormonal response typically occurring during continuous work. For this purpose in ten healthy men the heart rate (t _c), rectal temperature (T _re), oxygen uptake (VO₂), as well as blood metabolite and some hormone concentrations were measured during 2-h exercise at approximately 50% maximal oxygen uptake split into four equal parts by 30-min rest intervals during which body water losses were replaced. During each 30-min exercise period there was a rapid change in T _re and t _c superimposed on which, these values increased progressively in consecutive exercise periods (slow drift). The VO₂ showed similar changes but there were no significant differences in the respiratory exchange ratio, pulmonary ventilation, mechanical efficiency and plasma osmolality between successive periods of exercise. Blood glucose, insulin and C-peptide concentrations decreased in consecutive exercise periods, whereas plasma free fatty acid, glycerol, catecholamine, growth hormone and glucagon concentrations increased. Blood lactate concentrations did not show any regular drift and the plasma cortisol concentration decreased during the first two exercise periods and then increased. In conclusion, in spite of the relatively long rest intervals between the periods of prolonged exercise and the prevention of dehydration several physiological and hormonal variables showed a distinct drift with time. It is suggested that the slow drift in metabolic rate could have been attributable in the main to the increased concentrations of heat liberating hormones.     

Sleep deprivation and daily torpor impair object recognition in Djungarian hamsters

Sleep has been shown to play a facilitating role in memory consolidation, whereas sleep deprivation leads to performance impairment both in humans and rodents. The effects of 4-h sleep deprivation on recognition memory were investigated in the Djungarian hamster (Phodopus sungorus). Because sleep during the first hours after daily torpor has many similarities to recovery from sleep deprivation, the effects of spontaneous torpor on object recognition were also assessed. A 4-h sleep deprivation, starting immediately after an object learning task, diminished the ability of the hamsters to: (1) discriminate between an already encountered object (target) and a novel object presented in a novel context, (2) retrieve a target within a complex spatial scene, and (3) detect a spatial rearrangement of familiar objects in a familiar context. Plasma stress hormone levels were similar in sleep-deprived and control hamsters. The occurrence of a daily torpor episode during retention was associated with impaired old-new object discrimination performance in the more effortful complex spatial scene task only, and in a two-object choice situation in a novel context no torpor-induced deficit was found. Our results show that post learning sleep deprivation and daily torpor induce a deficit in familiar object retrieval performance in a complex spatial scene, while sparing familiarity-based recognition and novelty processing. Sleep deprivation during the first 4 h of memory consolidation hampered also recency memory for discrete objects. Stress was not a factor contributing to the sleep deprivation-induced impairment.     

自拟安胃汤联合兰索拉唑对老年胃溃疡患者胃肠激素及IL-6水平的影响

目的探讨老年胃溃疡患者给予自拟安胃汤联合兰索拉唑治疗对胃肠激素及白细胞介素(IL-6)水平的影响。方法选取2018年1月至2020年12月在本院治疗的老年胃溃疡患者84例作为研究对象,按照随机数字表法分成观察组(42例)和对照组(42例),对照组给予兰索拉唑治疗,观察组给予自拟安胃汤联合兰索拉唑治疗,比较两组患者胃肠激素及IL-6水平。结果两组治疗后胃泌素(GAS)、胃动素(MOT)水平明显提高(P<0.05),观察组水平较对照组明显更高(P<0.05);两组治疗后IL-6水平明显降低(P<0.05),与对照组相比,观察组明显更低(P<0.05)。结论老年胃溃疡患者给予自拟安胃汤联合兰索拉唑治疗,能够改善胃肠激素及IL-6水平,应用价值较高。     

Pediatric reference intervals for aldosterone, 17α-hydroxyprogesterone, dehydroepiandrosterone, testosterone and 25-hydroxy vitamin D3 using tandem mass spectrometry

Objectives

To determine age and sex-specific pediatric reference intervals for aldosterone, 17α-hydroxyprogesterone, dehydroepiandrosterone, testosterone, and 25-hydroxy vitamin D₃.

Background and design

Reference intervals were determined for neonates and children 0-18 years of age. The study was conducted at both Children's National Medical Center and Georgetown University using outpatient blood samples obtained between January 1, 2004 and June 30, 2008.

Methods

Serum samples were analyzed using isotope dilution liquid chromatography tandem mass spectrometry (LC/MS/MS) with deuterium-labeled internal standards at Children's National Medical Center and Georgetown University Medical Center Bioanalytical Core Laboratory.

Results and conclusions

This is the first study to provide pediatric reference intervals of steroid hormones for children from birth to 18 years of age using LC/MS/MS. Reference intervals were established for aldosterone, 17α-hydroxyprogesterone, dehydroepiandrosterone, testosterone, and 25-hydroxy vitamin D₃. All the analytes exhibited at least some age dependence. Sex differences between early and late childhood and adolescence were found for 17α-hydroxyprogesterone and testosterone. Seasonal differences were apparent for 25-hydroxy vitamin D₃.     

Quantitative monitoring of brain function,vital signs,and hormonal response during acute insulin-induced hypoglycemia

Acute insulin-induced hypoglycemia provokes changes in central nervous system activity and release of counterregulatory hormones. The clinical relationship between central nervous system activity, hormone secretion, and vital signs has not to our knowledge been previously reported. We used computerized electroencephalographic (CEEG) analysis to monitor 5 nondiabetic subjects during acute insulin-induced hypoglycemia (0.75 U/kg intravenous push). Their glucose nadir was 38±6 mg/dl (mean ± 1 SD). A three-phase pattern of change in CEEG power in response to hypoglycemia was observed: phase 1 was characterized by an increase in total CEEG power (natural log of activity = 9.1±1.3 µV²) over baseline (8.7±1.2 µV²) in the theta, delta, and beta frequency bands. This phase preceded and coincided with the glucose nadir. During phase 2, power in all frequency bands fell significantly below baseline. A nadir in CEEG power (8.0±1.6 µV²) occurred 40 to 55 minutes after insulin injection as glucose levels were rising. During phase 3 there was a return to baseline in CEEG power and frequency spectra. Heart rate increase just before phase 1; peak heart rate (91±8 beats/min) coincided with peak CEEG power and was significantly higher than basal rate (71±11,P<0.05). A significant increase in respiratory rate occurred during phase 1 of the CEEG and persisted through phase 2. A significant decrease in mean blood pressure (nadir = 73±6 mm Hg) below preinsulin blood pressure (81±8 mm Hg,P<0.05) coincided with the nadir of CEEG power in phase 2. Blood pressure returned to basal levels during phase 3. Peak plasma epinephrine (652±207 versus 46±30 pg/ml), norepinephrine (500±219 versus 273±107 pg/ml), and pancreatic polypeptide levels (1,023±689 versus 114±24 pg/ml) were all significantly elevated over respective basal concentrations (P<0.05). Peak hormone levels occurred during CEEG phase 2. This study demonstrates a temporal association of changes in CEEG power, vital signs, and hormonal secretion. These techniques may be applicable for further investigation of the clinical neuroendocrinology of the response to acute hypoglycemia.Supported in part by the Diabetes Research and Education Fund and the Juvenile Diabetes Foundation.The authors thank Diane Ogorzalek and Patsy Thomas for secretarial assistance and Pediatric Endocrine Unit nurses Debra Pitarra and Joyce Hylton. Baiba Pironis performed the catecholamine assays. Specific reagents for the human pancreatic polypeptide assay were provided through the courtesy of Dr Ronald Chance, Lilly, Indianapolis, IN. Presented in part at the 70th Annual Meeting of the Endocrine Society, New Orleans, June 1988, and at the Annual Meeting of the American Society of Anesthesiology, San Francisco, October 1988.     

Hormones and Sexuality in Postmenopausal Women: A Psychophysiological Study

Sexual function, including vaginal atrophy, and hormonal status, were studied in 42 naturally postmenopausal women. Vaginal pulse amplitude and subjective sexual responses during self-induced erotic fantasy and during erotic films were compared with responses of a small number of premenopausal women. As predicted, vaginal atrophy was related to estrogens but not to complaints of vaginal dryness and dyspareunia. No significant relationship was found between hormones and sexual function. Unexpectedly, most of the few correlations that did reach significance involved prolactin. The fact that prolactin was negatively associated with sexual desire, sexual arousal and vaginal lubrication during sexual activity, suggests that psychosocial factors are more important titan hormone levels in postmenopausal sexual function. Comparisons with a number of premenopausal women revealed that although postmenopausal women displayed lower vaginal pulse amplitude responses prior to erotic stimulation than the premenopausal women, this difference disappeared during subsequent erotic stimulation. We argued that this finding can be interpreted as being supportive of the notion that complaints of vaginal dryness and dyspareunia should not be attributed to vaginal atrophy associated with menopause. Rather, vaginal dryness and dyspareunia seem to reflect sexual arousal problems.