摘要:

AbstractDaily injections of testosterone propionate to castrated mice resulted in a striking increase in kidney weight. Renal putrescine rose sharply and the amounts of spermidine and spermine were also increased. The activity of ornithine decarboxylase was enhanced to values of more than 1 000 times the control level within a few days of testosterone substitution. A moderate and temporary increase in the activity of the putrescine‐activated S‐adenosyl‐L‐methionine decarboxylase was observed. Testosterone injections produced a large increase of renal RNA but only a minor change in DNA. It is apparent that in mice distinct alterations in polyamine metabolism occur during the development of renal hypertrophy induced by testosterone adminis

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1978.tb06085.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

AbstractPigmented rats were kept under different light regimens for 1–20 days. Supramaximal light was used. The response of the iris sphincter in enucleated eyes with their cornea intact was tested in vitro. Pilocarpine at 6 × 10‐5M was used as a standard stimulus. In agreement with previous authors there was a marked difference between constant light treated (subsensitive) eyes and dark treated (supersensitive) ones. Animals pretreated to reach maximal sub‐ and supersensitivity and then shifted to the opposite regimen, showed that reversal was a gradual process starting within a few hours. Full reversal had not been reached at 72 h. The two curves of sensitivity vs time intersected around 24 h. The time constants of the two curves were approximately equal. Light regimens using intermittent light shifting every 1, 3, 6 or 12 h gave intermediate r

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1978.tb06086.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

AbstractIn non‐hydrated goats prolonged (3 h, 0.02 ml/min) intracerebroventricular (IVT) infusion of 0.35 M glycerol depressed the plasma vasopressin level during the entire infusion period which resulted in a conspicuous water diuresis outlasting the infusion by about 20 min. Since no compensatory drinking occurred during this sustained water diuresis it gradually induced pronounced dehydration (loss of>1 liter of total body water causing 5% increase in plasma [Na+] and osmolality). The same degree of dehydration was in other experiments induced by water deprivation. It then caused a 5‐fold increase in plasma vasopressin level.Corresponding IVT infusions of 0.35 M d‐glucose depressed plasma vasopressin level only during the first half of the 3 h infusion period. Consequently, the resulting water diuresis was transient and subsided before the glucose infusion was finished.Plasma renin activity increased during the IVT glycerol infusion and during water deprivation, but was largely unaffected by IVT glucose. Both IVT glycerol and glucose decreased renal sodium excretion.The possibility is discussed that the pronounced ability of IVT glycerol to depress the vasopressin release and thirst is not only due to dilution induced reduction of CSF [Na+], but also to an influence of glycerol on choroidal and/or transependymal Na+‐transporting mec

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1978.tb06087.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

AbstractPotassium depolarization of rabbit colon muscle elicited a contraction consisting of 2 distinct phases, an initial rapid phasic contraction and a tonic contracture. The tonic contraction was, in contrast to the phasic contraction, dependent on the extracellular calcium for its development. There was a correlation between the tension development and the increase of the cyclic GMP level in the K+‐depolarized muscle. Experimental conditions which abolished the tonic contracture,vizglucose omission and treatment with Ca2+‐antagonists (verapamil, SKF 525A) also inhibited the cyclic GMP response. The changes of the cyclic GMP levels were Ca2+‐dependent. K+‐ions also changed the cyclic AMP content an effect which was atropine sensitive. From the experimental data obtained in this investigation we suggest that the co‐variation of the tension and the cyclic GMP level in the depolarized colon muscle might depend on oscillations in a common intracellular factor, prob

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1978.tb06088.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

AbstractThe effect of secretin on bile flow, biliary clearance of14C‐erythritol and bile composition was studied in fasting, chloralose anesthetized cats. Secretin (2 U · kg‐1·h‐1) increased bile flow by 85% and increased the rates of excretion of Na+, Cl‐and HCO‐3. Bile flow increased from values below to values above the erythritol clearance, which did not change significantly. It is therefore concluded that secretin altered ductular transfer of fluid from a net reabsorption to a net secretion of a bicarbonate rich fluid. Secretin did not affect the sphlanchno‐hepatic hemodynamics or the overall function of the liver and Indomethacin did not significantly alter the respons

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1978.tb06089.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

AbstractThe effect of the nonionic detergent Triton X‐100 (TX‐100) on the Na permeability (PNa) properties of the nodal membrane in myelinated nerve fibres ofXenopus laeviswas analysed with potential clamp technique. Application of TX‐100 caused a rapid initial decrease in PNathat was reversible at wash out as well as a slow irreversible block. Both effects depended on [TX‐100] and duration of exposure. The reversible reduction of PNaat the steady state was 50% at 40–60µM TX‐100. The slope of the Hill plot for the reaction was 1.75 indicating a deviation from a first order reaction. The equilibrium dissociation constant (KD) for n = 1.75 was 0.9 × 10‐7(M1.75). KDcalculated from the rate constants for onset and offset of the reversible reaction (KD= k2/k1) was 1.5 × 10‐7(M1.75). The possibility that the action of TX‐100 involves membrane p

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1978.tb06090.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

AbstractThe aim of the present study was to investigate whether substances known to antagonize algogenic agents can block an experimentally induced increased sensory nerve activity in the dental pulp of the cat. Increased neural activity following repeated brief heat stimulation has been shown to be characteristic of the individual cat and can be utilized for intraindividual comparative studies on such increased activity. When indomethacin, diclofenac sodium or naproxen were given intravenously as a pretreatment prior to stimulation, a consistent blocking effect on expected impulse activity as compared to the impulse activity in the control teeth was produced. Indomethacin produced a dose‐dependent inhibition (ID500.04–0.2 mg/kg). Diclofenac sodium (5 mg/kg) inhibited nerve activity by 51–91% and naproxen (15 mg/kg) by 92–95%. Methysergide (0.02–0.08 mg/kg) did not show such blocking effect. When the drugs were administered during a state of established increased neural activity no effect on the current impulse activity was obtained. The present results suggest that prostaglandins may be involved in certain stages of heat induced pulp inflammation and act as mediators of increased intradental sensory nerve exc

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1978.tb06091.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

AbstractThe importance of the sympatho‐adrenal system for the pancreatic hormonal response to exercise and, furthermore, the role of glucagon and catecholamines for the hepatic glycogen depletion during exercise were studied. Rats were either surgically adrenomedullectomized and chemically sympathectomized with 6‐hydroxydopamine or shamtreated. Two weeks later the rats had either rabbit‐antiglucagon serum or normal rabbit serum injected. Subsequently the rats either rested or swam with a tail weight for 75 min. Immediately afterwards cardiac blood was drawn and liver and muscle tissue collected. In control rats in spite of an increase in blood glucose concentrations during exercise plasma insulin concentrations were unchanged, while glucagon concentrations increased. In sympathectomized rats, compared to control rats, glucagon concentrations increased less, and insulin concentrations were higher, although glucose concentrations were lower during exercise. Sympathectomy completely abolished the exercise‐induced decrease in liver and muscle glycogen concentrations, whereas neither glycogen depletion nor plasma catecholamine concentrations were influenced by the administration of glucagon antibodies. These findings indicate that the sympatho‐adrenal system enhances glucagon secretion as well as muscular and hepatic glycogen depletion but inhibits insulin secretion in exercising rats. The increase in glucagon concentrations, however, does not enhance hepatic glycogen depletion at the work

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1978.tb06092.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

AbstractVascular reactions in the cat lower leg muscles in response to short‐term (10 min) hemorrhagic hypotension (˜80 mmHg) were studied before and after regional blockade of the β‐adrenoceptors. In the muscle region with intact β‐adrenoceptors, hemorrhage raised vascular resistance by about 80% and caused a dilatation of the precapillary sphincters, the latter effect evidenced in terms of a 35% increase of the capillary filtration coefficient. Concomitantly, an absorption of extravascular fluid to the blood stream occurred, a process tending to compensate for the reduction of intravascular fluid volume. After regional β‐blockade there was quite a marked augmentation of the hemorrhage induced increase of vascular resistance whereas the inhibition of precapillary sphincter tone and the transcapillary fluid absorption were almost abolished. These observations indicate that bleeding is associated with a significant β‐adrenergic dilator influence in both the resistance vessels and precapillary sphincters of skeletal muscle and that the β‐dilator mechanism may be essential for the important, compensatory fluid gain from the extravascular to the intravascular space during hemorrhage. The observed β‐adrenergic mediation of the net transcapillary fluid absorption could be ascribed to resetting of the pre‐/postcapillary resistance ratio, leading to decreased capillary hydrostatic pressure, and to the dilator influence in the precapillary sphincters, leading to an increased number of the patent capillaries available for the transca

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1978.tb06093.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

AbstractThe present experiments were undertaken to study the balance between vascular α‐ and β‐adrenoceptors in canine subcutaneous adipose tissue during sympathetic nerve stimulation and noradrenaline injections. Propranolol potentiated and prolonged the vasoconstrictor response to close i.a. injections of noradrenaline. The vasoconstriction induced by brief nerve stimulation (0.5 to 8 Hz) was, however, unaltered by the β‐adrenoceptor blockade. During prolonged nerve stimulation the vasoconstrictor response was well maintained at 1.5 Hz but at 4 Hz there was a gradual escape. The escape phenomenon at 4 Hz was diminished by propranolol. The β1‐selective antagonist practolol, like propranolol, potentiated and prolonged the vasoconstriction induced by noradrenaline injections and reduced the vasoconstrictor escape during prolonged nerve stimulation at 4 Hz. Furthermore, the vasodilatation induced by noradrenaline injection or nerve stimulation during α‐adrenoceptor blockade was diminished by practolol. Practolol also blocked the lipolytic response to noradrenaiine and nerve stimulation. The β2‐selective antagonist H35/25 blocked the effects of the β2‐selective agonist salbutamol but failed to alter noradrenaline as well as nerve stimulation induced vascular and lipolytic β‐adrenoceptor responses. The present results provide further support for the hypothesis that vascular β‐adrenoceptors in adipose tissue are humoral (noninnervated), preferentially activated by circulating noradrenaline. Moreover, both vascular and lipolytic β‐adrenoceptors activated by noradrenaline in adipose tissue are best c

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1978.tb06094.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY