Changes of hexose monophosphate pathway and methemoglobin reductase enzyme activity after radiation in guinea pigs

HMP pathway activity changes occurring after exposure to ionizing radiation (LD50 dose) have been investigated. The study was carried out on 18 experimental guinea pigs subjected to 5 successive exposures of 150 rads 3 or 4 days apart. The control animals were sham radiated but were otherwise treated identically as those of the experimental groups. Blood samples were taken by cardiac puncture before radiation and 30 min after each exposure of 150 rads. The red cells were re-suspended in their own plasma and HMP pathway activity was measured in the suspension. The pathway activity showed a consistent but minor reduction in the experimental group, which became statistically significant after the total dose of 750 rads (P less than 0.020). In a separate study the changes induced by ionizing radiation in the erythrocyte enzyme NADH-methemoglobin reductase were measured using the same experimental protocol. The enzyme activity in the red cells of the experimental group varied between 34.90 +/- 2.17 to 161.95 +/- 5.34 I.U./ml erythrocyte pack. Its activity declined toward the initial value after reaching the peak by the 12th day of ionizing radiation with 600 rads (P less than 0.001).     

Comparison of tracheal mucous transport in rats, guinea pigs, rabbits, and dogs

Tracheal mucous transport was measured using similar techniques in several species. One- to 10-microliter quantities of 99mTc-macroaggregated albumin (99mTc-MAA) were instilled via oral intubation in the distal trachea of rats, rabbits, and dogs. Tracheostomies were used for the instillation in guinea pigs. All animals were anesthetized with halothane for the instillation and allowed to recover immediately in restrainers. Clearance of the 99mTc-MAA in rats and guinea pigs was measured by a slit-collimated NaI scanner. In rabbits and dogs a series of gamma-camera scintiphotos were taken. Clearance was faster and more efficient in dogs than in the other species. No significant differences existed among the rats, rabbits, and guinea pigs in the percentages of the originally deposited material remaining at the instillation site after 1 h (P greater than 0.2). Mean values and standard deviations were 83 +/- 23%, 81 +/- 22% and 70 +/- 20% for rats, guinea pigs, and rabbits, respectively. However, in the dogs a mean of 14 +/- 12% remained at the original site of deposition after only 25 min indicating much more rapid clearance. Mean leading-edge velocities were 9.8 +/- 2.1 (SD) for dogs, 3.2 +/- 1.1 for rabbits, 2.7 +/- 1.4 for guinea pigs, and 1.9 +/- 0.7 mm/min for rats. Clearance patterns qualitatively among the species. In dogs the material moved as a few discrete boluses, whereas in the other species the activity spread toward the larynx. The relatively slow mucous transport of rats, rabbits, and guinea pigs could have important implications in inhalation toxicological studies.     

Bronchoalveolar eosinophilia in guinea pigs harboring inapparent infections of Paraspidodera uncinata

During the course of experiments examining the changes in cell populations in bronchoalveolar lavage (BAL) fluid in 3-11-wk-old guinea pigs, a marked increase in the numbers of eosinophils was observed in BAL fluid in untreated control animals from historical levels (observations made over the previous 2 yr) of 8.8 +/- 1.5% to levels greater than 16% and up to 44%. Repeated occurrence of this phenomenon in several different groups of guinea pigs that appeared clinically normal and the impact on our experimental studies led us to attempt to identify the cause of increased inflammatory cell numbers in these guinea pigs. Examination in 2 groups of animals of whole blood and lung tissue for the presence of bacteria or fungi revealed minor bacterial infections in one group but not the other, whereas both exhibited elevated eosinophil numbers. At necropsy, 41.7% and 60% of the animals in the 2 groups harbored the nematode Paraspidodera uncinata. Guinea pigs exhibiting eosinophil numbers in BAL fluid comparable to our historical levels were then inoculated with approximately 100 embryonated eggs of P. uncinata and developed elevated eosinophilia in BAL fluid compared to sham-inoculated animals (significant at 2 of the 3 examination times postinoculation). These findings suggest that P. uncinata is capable of causing changes in inflammatory cell populations in the lungs of guinea pigs and illustrate the importance of subclinical or inapparent infections in experimental design and interpretation.     

Increased erythrocyte glutathion reductase activity in a hemoglobin Porto Alegre (β9 Ser → Cys) carrier

Erythrocyte glutathion reductase activity in a homozygous carrier of hemoglobin Porto Alegre have been found to be increased three times as compared to a normal subject and the level of reduced glutathion is also increased to twice the value found for a normal subject.The time course of the decrease of glutathion reductase activity, in the stored hemolyzate, is found to be inversely correlated to the proportion of hemoglobin Porto Alegre disulfide polymer formed. Our results strongly suggest that during the in vitro formation of the disulfide polymer, a molecule of glutathion reductase is also involved by disulfide bridge formation, which appear to explain the rapid decrease of the enzyme activity upon storage, in spite of the fact that glutathion reductase is a very stable enzyme.     

Changes in phospholipase A2 in myometrium of the guinea pig uterus during pregnancy.

Phospholipase A2 activity has been measured in membrane and cytosolic fractions from non-pregnant and pregnant guinea pig myometrium has been studied. Enzyme activity was measured with 1-stearoyl-2- [3H]arachidonoyl-phosphatidylcholine exhibiting Michaelis-Menton kinetics with Km of 83.8 +/- 21.6 and 53.2 +/- 14.1 for membrane and cytosolic enzymes respectively. Fractionation of the myometrium from non-pregnant guinea pigs suggested that 35% of the activity was membrane associated compared with 20% (P < 0.01) in tissue from pregnant animals. In the presence of 1 mM calcium total activity rose from 3.03 +/- 0.41 to 1737 +/- 368 nmol/h per uterus between non-pregnant and late pregnancy. Calcium activated the membrane enzyme, but the effect was greater late in pregnancy with almost a 6-fold increase in activity at 1 mM calcium compared with a doubling in membrane from non-pregnant guinea pigs. The K0.5 for calcium activation was about 150 microM. Immunoblotting with anti-human-110 KDa phospholipase A2 showed in guinea pig uterus a 34 KDa form of the enzyme that, consistent with changes in activity, showed a fifteen-fold increase in quantity between non-pregnant and late pregnancy. The data are consistent with dramatic increases in the capacity for arachidonic acid release and prostaglandin production in the guinea pig myometrium late in pregnancy.     

褪黑素对顺铂的听觉中枢毒性的影响

目的：研究顺铂的中枢听觉毒性以及褪黑素对其的保护作用。方法：用顺铂和不同浓度褪黑素分别在豚鼠左右腹腔注射7d后,用分光光度计测量听皮层脑组织LDH活力、MDA、NO含量。结果：顺铂注射7d后各组的体重均下降,其中以单独注射顺铂组和10mg·kg^-1·d^-1褪黑素加顺铂组下降趋势最明显,较处理前有显著差异（P〈0．01）。顺铂组动物听皮层LDH活力水平明显高于生理盐水组（P〈0．01）;褪黑索能显著降低顺铂引起的听皮层脑组织中的LDH增高（P〈0．05）。豚鼠腹腔注射顺铂7d后听皮层MDA含量较腹腔注射生理盐水组明显增高（P〈0．01）;同时腹腔注射褪黑素能降低听皮层组织MDA含量（P〈0．05）。各药物作用后听皮层的NO含量变化统计学比较无显著性意义。结论：腹腔注射顺铂能够作用于听皮层引起细胞损伤。褪黑素对顺铂所致的听皮层细胞损伤有防护作用,机制可能与其抗自由基作用有关。     

Role of thromboxane receptors in Forssman shock in guinea pigs

Forssman shock is a bronchospastic reaction mounted in guinea pigs on intravenous administration of an antiserum obtained from rabbits immunized against sheep erythrocytes. The involvement of thromboxane receptors in Forssman shock was determined with SQ 30,741, which was characterized as a selective antagonist of these receptors in guinea pig airways in vitro and in vivo. A volume of antiserum producing consistent, sublethal bronchoconstriction was given either alone (control) or 3 min after SQ 30,741 (0.03, 0.3, or 1.0 mg/kg iv) to urethan-anesthetized guinea pigs. In controls, maximum reductions in dynamic compliance (-59 +/- 6%, P less than 0.01) and increases in airways resistance (383 +/- 97%, P less than 0.01) were detected 1 min after antiserum. Both responses were significantly inhibited by SQ 30,741, either partially at 0.03 mg/kg or completely at 0.3 mg/kg. An accompanying thrombocytopenia was not abated by SQ 30,741. In separate experiments, bronchospasm was reduced by aerosol administration of 0.1% SQ 30,741 and completely prevented by aspirin (10 mg/kg iv). When Forssman antiserum was injected in lethal quantities to other guinea pigs, SQ 30,741 (1 mg/kg iv) attentuated only the resistance component of bronchospasm and did not prevent death. These data demonstrate that thromboxane receptor stimulation is a pivotal step in the pulmonary manifestations of sublethal Forssman shock but is less crucial in more severe forms of the reaction.     

花色豚鼠与白化豚鼠静脉血电解质、酸碱平衡及血气的比较学研究

目的比较研究花色豚鼠与白化豚鼠静脉血电解质、酸碱平衡及血气情况。方法分别取健康成年花色豚鼠和白化豚鼠,利用便携式多功能麻醉机经异氟烷吸入麻醉后,腹主静脉取血,经NOVA血气．电解质分析仪全自动分析测定电解质、酸碱平衡及血气等指标。结果花色豚鼠的Cl-、pH、SBC、PO2、SV O2、O2ct均显著低于白化豚鼠（P〈0．05,P〈0．01）,而PCO2显著高于白化豚鼠（P〈O．05）。结论花色豚鼠的携氧能力明显低于白化豚鼠,可以作为血瘀证和亚健康模型研究较好的实验动物。     

PCO(2) in the large intestine of mice, rats, guinea pigs, and dogs and effects of the dietary substrate.

PCO(2) in the lumen and serosa of cecum and colon was measured in rats, guinea pigs, and dogs to examine the relationship between serosal PCO(2) and the incidence of intestinal necrotic lesions after administration of gas-carrier contrast agents in rodents. The effects of the dietary substrate were tested in a group of mice maintained on a diet based on glucose as the only carbohydrate source. The anesthetic used was a fentanyl-fluanison-midazolam mixture (rodents) and pentobarbital (dogs). PCO(2) was measured in vivo and postmortem, and the kinetics of the postmortem serosal PCO(2) [transmural CO(2) flux (J(CO(2)))] was calculated. PCO(2) in the cecal serosa and lumen, respectively, was 64 +/- 4 and 392 +/- 18 Torr in rats, 67 +/- 3 and 276 +/- 17 Torr in guinea pigs, and 73 +/- 6 and 137 +/- 7 Torr in mice on glucose-based diet. In the colon serosa and lumen of dogs, PCO(2) was 30 +/- 6 and 523 +/- 67 Torr, respectively. Serosal PCO(2) increased rapidly after death in rats and slower in guinea pigs and mice, and the slowest change was observed in dogs. Compared with dogs, serosal PCO(2) and J(CO(2)) of rats and guinea pigs were significantly higher. Serosal PCO(2) of guinea pigs was similar to that of rats, whereas the J(CO(2)) of guinea pigs was significantly lower. These data suggest a causal relationship between the ability of the cecal and colonic wall to act as a barrier to CO(2) diffusion and the presence of characteristic gas-carrier contrast agent-induced intestinal lesions in mice and rats and their absence in guinea pigs, dogs, and other species.     

豚鼠眼形觉剥夺后恢复期的生物学参数变化规律探讨

目的探讨豚鼠眼球形觉剥夺后恢复期的生物学参数变化规律。方法普通级2～3周龄豚鼠30只,随机分为两组：①实验组：20只,右眼采用半透明眼罩遮盖进行形觉剥夺4周,随后去遮盖3周,左眼作为自身对照;②正常对照组：10只,双眼不进行任何干预,开放饲养7周。形觉剥夺前、形觉剥夺4周后及去遮盖后第2、6、10、14和21天,测量豚鼠双眼生物学参数：睫状肌麻痹后行带状光检影测量屈光度;A超测量前房深度、晶体厚度和眼轴长度,计算出玻璃体腔长度。结果经过4周形觉剥夺,实验组豚鼠右眼向近视漂移,屈光度为（-2.88±2.30）D,诱导了（-5.50±1.9）D相对近视。去遮盖后,豚鼠右眼重新正视化,屈光度恢复的快速期发生在6 d内,14 d时双眼屈光度差值差异无显著性（t=-2.049,P=0.080）,为（-0.18±0.26）D;右眼玻璃体腔长度缩短,14 d时双眼玻璃体腔长度差值差异无显著性（t=1.652,P=0.14）,为（0.0234±0.0400）mm;右眼眼轴长度缩短,14 d时双眼眼轴长度差值差差异无显著性（t=1.443,P=0.192）,为（0.0183±0.0359）mm。与正常对照组右眼相比,去遮盖6 d,屈光度差异为（-0.48±0.36）D,差异无显著性（t=-1.325,P=0.206）,而2 d时玻璃体腔和眼轴长度差异分别为（0.0961±0.0630）mm、（0.0621±0.0386）mm,差异无显著性（t=1.652,P=0.14;t=1.607,P=0.125）。结论 2～3周龄豚鼠去除形觉剥夺后可以重新进行正视化,伴随玻璃体腔和眼轴长度缩短;去遮盖6 d内为眼生物学参数恢复的主要时期。     

强噪声对豚鼠认知功能和血清某些生化指标的影响

目的：探讨强噪声对豚鼠认知功能和血清应激激素、代谢酶、神经肽、脑红蛋白等的影响,筛选噪声性认知功能损伤的敏感指标。方法：将24只豚鼠进行5 d的认知功能训练,第6天随机分为2组（n=12）：噪声组和对照组。噪声组在120 dB噪声下连续暴露4h后,用Morris水迷宫测试豚鼠的认知能力;用Elisa试剂盒检测豚鼠血清神经肽Y（NPY）、神经肽P（NPP）、脑红蛋白（NGB）、C反应蛋白（CRP）、皮质醇（CORT）、促肾上腺皮质激素（ACTH）、促肾上腺皮质激素释放激素（CRH）、肾上腺素（E）、去甲肾上腺素（NE）、血管紧张素Ⅱ（AngⅡ）、醛固酮（ALD）、催产素（OT）、血管升压素（VAP）含量、谷草转氨酶（ALT）、谷丙转氨酶（AST）、乳酸脱氢酶（LDH）、肌酸激酶（CK）的活性;用回归分析评价各项敏感指标对认知功能的影响及程度。结果：Morris水迷宫测试显示,与对照组相比,噪声组豚鼠的平均逃避潜伏期明显延长,跨越平台次数和目标象限停留时间均明显降低（P<0.01）。Elisa检测发现,除AngⅡ外,噪声组豚鼠血清中上述指标均与对照组有明显的统计学差异（P<0.05,P<0.01）,其中变化显著且对认知功能影响较大的指标依次为CORT、NPY、NE、NGB、NPP、CK。结论：强噪声急性暴露引起豚鼠认知功能显著下降,可能与外周血应激激素、代谢酶、神经肽、脑红蛋白等生化指标的异常有关,并初步筛选出了CORT、NPY、NE、NGB、NPP、CK等与噪声性认知功能损伤有关的敏感指标群。     

Antigenic determinants of hen egg-white lysozyme in delayed hypersensitivity. II. Antigenicity and immunogenicity of the N- and C-terminal peptide.

Various small fragments of (see article) which is one of the immunodominant groups of hen egg-white lysozyme (HL), were tested for macrophage migration inhibition (MMI) of peritoneal exudate cells (PEC) from guinea pigs immunized with HL. P17 was split in the middle with cyanogen bromide. The terminal portion of (see article) showed positive MMI, whereas the non-terminal half of P17, P17i (sequence 13-27) only showed very weak MMI activity. A fragment derived from the middle portion of P17, P17m (sequence 11-22), was inactive. When P17 were reduced and alkylated, one of the resultant peptides, P17N (sequence 1-[CM-Cys-6]-27) still has MMI activity with PEC taken from guinea pigs immunized with HL, although no antibody reacting with it was detected, but P17C (sequence 123-[CM-Cys-127]-129) was inactive. The peptides P17 and P17N were both immunogenic in guinea pigs in respect to the delayed hypersensitivity response. Again P17t and P17N were immunodominant groups, but the reactivity of P17i in MMI assay of this group of animals was greater than that in guinea pigs immunized with HL. The reactivities of HL with PEC taken from guinea pigs immunized with P17 or P17N were generally weaker than those of the antigens used for immunization.     

Substance P-induced effects in guinea pig lungs: effects of thiorphan and captopril

The effects of the neutral metalloendopeptidase inhibitor, thiorphan, and the angiotensin-converting enzyme inhibitor, captopril, on the changes in airway opening pressure (PaO), pulmonary arterial pressure (Ppa), and weight induced by intravascular administration of substance P were examined in isolated perfused and ventilated guinea pig lungs. Administration of 1 nmol substance P without enzyme inhibitors resulted in a significant (P less than 0.01) increase in the peak PaO during ventilation from 12.4 +/- 0.5 to 22.4 +/- 2.2 cmH2O; there were small statistically insignificant increases in Ppa. The changes in PaO peaked approximately 30 s after peptide infusion and returned to preinfusion values by 5 min. In the presence of combined thiorphan (5.6 microM) and captopril (7.7 microM) the magnitude of the Pao response at 30 s (41.5 +/- 3.8 cmH2O) and at 5 min (40.0 +/- 3.6 cmH2O) after peptide infusion was significantly greater than in control lungs (P less than 0.05). The effects of substance P on PaO in the presence of the various inhibitors were not related to amount of peptide recovered in the lung effluent. Reverse-phase high-performance liquid chromatographic analysis of [3H]Pro2,4 substance P perfused through the lungs demonstrated that the major products were consistent with intact substance P, substance P 1-4, and smaller peptides; only minor amounts of products consistent with substance P 1-7, 1-9, or 3-11 were identified. These data support our previous findings showing that the physiological effects of intravascular substance P are limited by peptide degradation; the latter process, once begun, proceeds rapidly to nearly complete peptide degradation.     

Temperature dependence of the maternal-fetal electrical potential difference in guinea pigs

An electrical potential difference (PD) is measured between maternal organism and fetus in the pregnant guinea pig. To investigate whether the PD is generated by active or passive forces these studies examined the temperature dependence of the PD in guinea pigs at 55-61 days gestation. Anesthesia was induced (ketamine, 44 mg/kg) and maintained (halothane, 1.5%) in 5 pregnant guinea pigs. The animals were subjected to alternating 1 hour periods of cooling and recovery, changing core body and intrauterine temperature about 5 degrees C. PD was monitored continuously with Ag/AgCl electrodes placed in the maternal abdominal cavity and the amniotic fluid. The resting PD (+/- SEM) was 24.1 +/- 2.8 mV. Analysis of covariance indicated that PD decreased slowly with time and increased significantly with lowered temperature. A second group of 4 guinea pigs was studied after beta blockade with propranolol (0.1 mg iv, repeated hourly). In this group the resting PD was 20.7 +/- 3.6 mV. The PD decreased gradually with time and decreased consistently during cooling. In the propranolol group the relation between PD and temperature yielded a calculated activation energy of 11.7 +/- 0.8 kcal/mol (Q10 = 1.9, 30-40 degrees C). These results are consistent with the hypothesis that at least some of the PD is generated by an energy-dependent electrogenic ion pump, or by selective passive diffusion of ions across a lipid membrane during which a significant energy barrier is overcome. They are not consistent with the generation of the PD exclusively by passive streaming of ions through water-filled channels. During cooling catecholamines are presumably released, favoring the generation of the PD.     

哮喘豚鼠肺、肝组织中还原型谷胱甘肽、γ谷氨酰半胱氨酸合成酶及其重链mRNA的表达

目的研究支气管哮喘（简称哮喘）豚鼠肺、肝组织中还原型谷胱甘肽（GSH）、γ谷氨酰半胱氨酸合成酶（γ-GCS）活性及其重链（γ-GCSh）mRNA表达的差异和变化。方法取健康雄性豚鼠30只,随机分为哮喘组（A组）、地塞米松治疗组（B组）及对照组（C组）,每组10只。采用腹腔内注射联合雾化吸入卵清蛋白复制哮喘豚鼠模型,用生物化学反应比色法检测各组豚鼠肺、肝组织中还原型谷胱甘肽（GSH）、总谷胱甘肽（TGSH）和γ-GCS的活性,用逆转录-聚合酶链反应（RT-PCR）法检测各组豚鼠肺、肝组织中γ-GCSh mRNA的表达。结果A组豚鼠与B组、C组比较肺内γ-GCS活性及γ-GCSh mRNA的表达明显升高,相应的总谷胱甘肽水平增加（P均〈0.01）,但GSH水平较对照组、治疗组下降（P〈0.05）;肝脏组织内γ-GCS活性、γ-GCSh mRNA的表达、TGSH及GSH浓度A、B、C三组比较差异无统计学意义（P均〉0.05）。结论哮喘豚鼠肺内γ-GCS、TGSH及γ-GCSh mRNA表达增高,并可能在抗氧化损伤中发挥重要作用,而TGSH、GSH、γ-GCS及γ-GCSh mRNA在哮喘豚鼠肝脏局部表达无变化。     

间歇性低压低氧对过氧化氢心肌细胞损伤的保护作用

目的:观察慢性间歇性低压低氧对过氧化氢所致心肌细胞损伤的保护作用及其机制。方法:雄性豚鼠20只,随机分为两组(n=10):对照组(non-IHH)、低氧组(IHH)。低氧组豚鼠于低压氧舱接受28 d(海拔5 000 m、每天6 h)的低压低氧处理。胶原酶方法急性分离心肌细胞。细胞动缘探测系统测定过氧化氢对各组细胞收缩力的变化。生化方法测定各组丙二醛(MDA)、乳酸脱氢酶(LDH)及超氧化物歧化酶(SOD)和过氧化氢酶(CAT)的变化。结果:①过氧化氢可使心肌细胞出现收缩、舒张紊乱,但IHH处理使其出现的潜伏期明显延长。②给予过氧化氢(300μmol/L,10 min)使来自于non-IHH或IHH的心肌细胞LDH、MDA含量均明显增加,但IHH心肌细胞LDH、MDA含量明显低于non-IHH心肌细胞的LDH、MDA含量。③经IHH处理组的心肌细胞SOD,CAT活性均明显高于non-IHH组。给予过氧化氢使来自于non-IHH或IHH的心肌细胞SOD,CAT活性均明显降低,但IHH心肌细胞SOD,CAT活性明显高于non-IHH心肌细胞的SOD,CAT活性。结论:IHH具有对抗过氧化氢心肌细胞损伤的作用,可能与其增强抗氧化酶活性有关。     

Hyponatremia-induced brain edema in guinea pigs is reduced by treatment with the novel anion transport inhibitor L-644,711

Cerebral edema in various disease states may result from astroglial swelling due to increased NaCl uptake mediated by enhanced Cl-HC03 exchange. We evaluated this mechanism in the pathogenesis of cerebral edema in acute hyponatremia by administering L-644,711, a fluorenyloxyacetate derivative that functions as an anion exchange inhibitor, to guinea pigs with severe reductions in serum Na+ concentration. Acute hyponatremia was induced for 54 hr by daily injections of arginine vasopressin (10 U/day) and 5% dextrose in water (7.5% body wt/day). Experimental animals received L-644,711, 20 mg/kg/day, while controls were given an equal volume of the diluent. This regimen lowered the serum Na from normal levels to 108 +/- 3 and 109 +/- 4 mM in experimental and control animals, respectively. Drug treatment resulted in less cerebral edema characterized by a reduction in brain total tissue water 432 +/- 4 vs 466 +/- 8 ml/100 g dry wt experimental vs control, P less than 0.005. This difference was composed mainly of less expansion of the intracellular water space, 287 +/- 11 vs 323 +/- 9 ml/100 g dry wt experimental vs control, p less than 0.005. The cerebral cortical Na+ +Cl content was reduced from 55.5 +/- 1.3 (control) to 39.5 +/- 1.1 mEq/100 g dry wt (experimental), p less than 0.01. These results indicate that treatment of guinea pigs with L-644,711 decreases brain NaCl content and attenuates cerebral edema during severe acute hyponatremia without normalizing the serum Na+ concentration.     

Endometrial arylamidase activity in the guinea pig: changes during the oestrous cycle, decidualization and ovarian steroid hormone treatment.

1. As suggested by comparative studies done in various species, amino acid arylamidases (amino peptidases) may play a role in blastocyst implantation. 2. Histochemical studies of the guinea pig endometrium indicate that arylamidase increases in the stroma during pregnancy but is depleted in the vicinity of the blastocyst during implantation. 3. To further explore the possible significance of arylamidases in uterine function, endometrial arylamidase activity was measured in guinea pigs during the reproductive cycle, decidualization and after ovariectomy with and without estrogen (E) and/or progesterone (P) treatment. Arylamidase activity was maximal during pro-oestrus-oestrus (40.0 +/- 10.0 mu/mg protein). 4. Enzyme activity was markedly depleted in decidualized endometrial stroma (12.3 +/- 1.6, P less than 0.01); reduced by ovariectomy (20.5 +/- 2.7); and stimulated by E (29.2 +/- 1.2); P had little effect (21.9 +/- 3.5). 5. The physiological significance of modulation of endometrial arylamidase activity by steroid hormones is discussed.     

A comparison of the effect of inhaled diuretics on airway reflexes in humans and guinea pigs.

The effects of nebulized diuretics on citric acid-induced cough and airway obstruction in guinea pigs and capsaicin-induced cough and increase in airway resistance in humans have been studied. Half-maximum inhibition of cough in the guinea pig was produced by 1.3 mM furosemide and 0.25 mM hydrochlorothiazide. Cough was inhibited by 78 +/- 9% by 3 mM furosemide (P less than 0.05) and 89 +/- 11% by 3 mM hydrochlorothiazide (P less than 0.01). At the same time, airway obstruction was inhibited by 50 +/- 9% (P less than 0.001) and 42 +/- 15% (P less than 0.05), respectively. Nebulized furosemide (3 mM) was without effect on the airway obstruction produced by inhaled histamine or acetylcholine in the guinea pigs. Intravenously administered furosemide (270 nmol/kg) did not affect citric acid-induced responses. In humans, aerosolized furosemide (9 mM) and hydrochlorothiazide (3.4 mM) reduced the percent increase in respiratory resistance from 22.1 +/- 3.7 and 15.6 +/- 3.4 to 10.5 +/- 4.9 and 9.4 +/- 3.3%, respectively (P less than 0.05), but were without effect on cough due to capsaicin. Thus both furosemide and hydrochlorothiazide inhibited airway obstruction in the guinea pig and reduced the capsaicin-induced increase in airway resistance in humans. However, whereas coughing was inhibited in the guinea pig, neither drug affected cough in humans. This difference in the action of the loop diuretic and thiazide, which interact differently with Na(+)-K(+)-Cl-transport within the airway mucosa, on the cough and airflow obstruction in guinea pig and humans supports the view that different sensory limbs are involved in these reflexes.(ABSTRACT TRUNCATED AT 250 WORDS)     

Thyroxine and triiodothyronine in milk of cows, goats, sheep, and guinea pigs

Milk was collected for the first 21 days of lactation twice daily from dairy cows and once daily from goats, sheep, and guinea pigs. Thyroxine (T4) and triiodothyronine (T3) were extracted from 100 microliter of milk using acidified ethanol. T4 and T3 were reconstituted in 100 microliter buffer and measured by radioimmunoassay. Concentrations (ng/ml) of T4 and T3 for milk of cows, goats, sheep, and guinea pigs, respectively, were: 0.97 and 0.94, 1.24 and 0.52, 0.99 and 0.79, and 1.41 and 0.53. T4 concentration for guinea pig milk was significantly higher than for cow and sheep milk, but not for goat milk (P less than 0.05). T3 was found in higher concentration in milk of cows and sheep than in milk of goats and guinea pigs (P less than 0.05). Species differences in conversion of T4 to T3 in mammary gland cells are suggested. Summations of T4 and T3 concentrations in milk indicated no differences among the four species. Regression analyses of changes in milk production, T4 and T3 concentrations, total T4 and T3 in milk per day, and ratios of T4 to T3 revealed variations in patterns. Concentrations of T4 or T3 tended to decrease as lactation progressed over 21 days. Total T3 tended to increase, and the ratio of T4 to T3 tended to decrease. Amounts of T4 and T3 available to offspring from milk were calculated to be minor sources (4 to 7%) of total requirements for maintenance of metabolic functions.