bluuebunny/crossref_metadata_2025 huggingface dataset:
Role of magnesium in contraction of glycerinated muscle fibers
Authors: Watanabe Shizuo , Sargeant Tania , Angleton Marita
Published: December 2017

The first phase of the magnesium effect, the increase in tension with increasing concentration of magnesium, up to about 25 µm, is abolished by the metal chelators DCTA and EDTA, but not by EGTA. DCTA is much stronger than EDTA in abolishing this first phase. The second phase of the magnesium effect, the decrease in tension with increasing concentration of magnesium, from about 25 µm to about 1 mm, is reduced when the concentration of ATP is decreased from 5 mm to about 0.5 mm. The third phase, the increase in tension with increasing concentration of magnesium to above 1 mm, is also reduced by metal chelators. However, EGTA is the strongest and DCTA is the weakest in reducing this third phase. From these observations, it is suggested that the first and the second phases are due to Mg (probably in the form of Mg-ATP complex) and that the third phase reflects the effect of a small amount of Ca which has been well established ( J. Biochem., Tokyo 50: 236–244, 1961 and J. Biol. Chem. 234: 2764–2769, 1959).
Fat metabolism of the hedgehog during the hibernating cycle
Authors: Konttinen A. , Rajasalmi M. , Sarajas H. S. S.
Published: December 2017

Lipid constituents of the serum, liver, omental fat, and brown fat were studied in nonhibernating, hibernating, and arousing hedgehogs. In the hibernating state the serum free fatty acid (FFA) content was decreased, with an associated hypoglycemia. The serum glyceride-glycerol also was reduced in hibernation, while the serum total cholesterol, its fractions separated electrophoretically, and the serum phospholipids showed the opposite trend. In the hibernating animals there was a threefold rise in the brown fat FFA content which suggests an intense breakdown of fats (hydrolysis of triglycerides) in this tissue during hibernation. During arousal, as the blood glucose level rose, the serum FFA decreased further. Meanwhile, there was an increase in the FFA content of the omental and brown fats, with a concomitant decrease in the liver FFA. It seems evident that during arousal the combustion of FFA exceeds their release from the fat stores.
Formation of hepatic lymph
Authors: Krebs J. S. , Brauer R. W. , Bollman J. L. , Leong G. F.
Published: December 2017

Samples of hepatic lymph collected from isolated perfused rat livers or from livers of whole rats, during continuous infusion of BSP, showed two types of response with respect to content of BSP. One of these was characterized by lymph BSP concentrations below those in blood plasma, and a chromatographic composition of lymph BSP different from that in both plasma and bile. In the other response BSP concentrations in lymph were grossly higher than those in plasma, and the chromatographic composition of the BSP was identical with that in bile. The second response was observed whenever bile flow was deliberately arrested, but it also occurred when bile was apparently flowing freely, suggesting that a type of nonobstructive, nonhemolytic jaundice could exist, based on failure of labile mechanisms which normally prevent diffusion of biliary substances into the extracellular space. The chromatographic composition of the BSP in responses of the first type suggests that part of the BSP in hepatic lymph normally arises from the hepatic cells, rather than from either the blood plasma or the bile.
Vasodepressor responses elicited by diencephalic stimulation in dogs
Authors: Gorten Ralph J. , Smith Orville A. , Rushmer Robert F.
Published: December 2017

Tachycardia and peripheral vasoconstriction are the usual means by which the cardiovascular system, under nervous control, attempts to compensate for a lowering of pressure in the systemic arteries. When such compensatory efforts are absent during sudden, unexpected periods of hypotension, an alteration in central nervous system control should be suspected. The possibility of producing such alterations in the control of the circulation under experimental conditions was studied in five anesthetized dogs. Diencephalic areas were found in which electrical stimulation evoked a lowering of arterial pressure in the absence of tachycardia. Electrodes were chronically implanted in these areas so that stimulation could be performed in the unanesthetized state. The observed effects on the cardiovascular system were not always the same as those induced while the animals were anesthetized. The decrease in arterial pressure was usually less in extent. Occasionally an actual rise in pressure occurred, followed after the period of stimulation by a decrease in arterial pressure and heart rate.
Transient changes in electrical potential differences across frog skin
Authors: Kidder George W. , Cereijido Marcelino , Curran Peter F.
Published: December 2017

The time course of changes in potential difference across frog skin ( Rana pipiens) following rapid changes in composition of the bathing solutions has been investigated. Increasing Na concentration in the outside solution results in a rapid rise in potential difference which is nearly complete in 0.4–0.5 sec. Analysis of the time course of this change strongly suggests the presence of a barrier to Na movement located quite near the anatomical outside of the skin. The change in potential difference following changes in the K concentration of the inside solution is much slower, and is consistent with the location of the K-sensitive barrier 150–250 µ from the inner surface of the skin.
Biliary excretion of dihydro-11-keto-progesterone-4-C14 by isolated perfused liver
Authors: Leong G. F. , Cazes D. M. , Berliner M. L. , Berliner D. L.
Published: December 2017

The rates of biliary excretion of dihydro-11-keto-progesterone-4-C14 and of its metabolites were studied in the isolated perfused rat liver. The half-life of this steroid in the perfusing blood was 2.5 min, and at 40 min about 75% of the injected steroid had been excreted in bile. Formation of water-soluble steroids (WS St) took place at a rapid rate and by 60 min 100% of the steroids in blood were found to be water soluble. During the entire study the steroids excreted in bile were water soluble and accounted for 97.2–100% (avg. 98.2%). No dihydro-11-keto-progesterone was found to be excreted in the bile. The rate of disappearance from the blood, excretion in the bile, and degree of formation of WS St of this compound when compared with corticosterone and cortisol shows the following pattern: dihydro-11-keto-progesterone > corticosterone > cortisol.
Effect of hemolysis on excretion and accumulation of iron in the rat
Authors: Kaufman Richard M. , Pollack Simeon , Anderson Pearl , Crosby William H.
Published: December 2017

Two groups of rats were injected intraperitoneally with tracer amounts of Fe59 Cl3 and the rate of loss of radioactivity was measured over a period of 105 days. Both groups of rats were maintained on a regular rat pellet diet but the experimental group also received acetylphenylhydrazine weekly in order to induce hemolytic disease. At the end of the experiment all rats were killed and the body iron content of each determined. It was observed that the fraction of body iron lost daily was markedly increased in rats undergoing hemolysis. Further, these rats accumulated iron in excess of normal, indicating that iron absorption was increased to a greater extent than was iron excretion.
Effects of fibrinolytic agents and heparin on intravascular clot lysis
Authors: Lewis Jessica H. , Kerber C. W. , Wilson John H.
Published: December 2017

Clots were prepared in glass or siliconized cannulae and inserted into jugular veins 5 cm distal to semiconstricting ligatures. Clots prepared in glass tubes propagated rapidly unless heparin was administered. Clots prepared on siliconized surfaces showed less tendency to grow. Heparin was the most effective agent in causing decrease in clot size (thrombolysis). The thrombolytic effects of the fibrinolytic agents were somewhat less than heparin and did not correlate well with their in vitro activities. Staphylokinase, dog fibrinolysin, and bromelain proved too toxic for adequate testings. Following Thrombolysin or Actase infusions the plasma fibrinolytic titers rose and the profibrinolytic and antifibrinolytic titers fell. Following streptokinase (SK) the plasma fibrinolytic titer rose but no changes in antifibrinolysin or profibrinolysin were observed. It was postulated that the apparent rise in fibrinolysin following SK may have been due to simultaneous adsorption of activator and profibrinolysin onto the substrate followed by in situ activation. Heparin caused no detectable changes in the dogs' fibrinolytic factors.
Noradrenaline and normetadrenaline metabolism in portal cirrhosis
Authors: Goodall McC. , Alton Harold , Henry Martha
Published: December 2017

Four patients with moderate to severe portal (alcoholic) cirrhosis were injected intravenously with dl-noradrenaline-2-C14. Urine was collected via an indwelling catheter at 10-min intervals for 1 hr and thereafter for 6 and 24 hr. The metabolic products of noradrenaline were separated, identified, and their radioactivity measured. The same subjects were also injected with dl-normetadrenaline-1-C14, the O-methylated metabolic product of noradrenaline, and the urine samples similarly processed. The results seem to indicate that in portal cirrhosis noradrenaline metabolism is altered. In the period immediately following the injection of noradrenaline there is a slight decrease in the catechol-O-methyl transferase activity but thereafter it is either unchanged or slightly increased. Further, the cirrhotic shows a distinct predilection for conjugating both noradrenaline and normetadrenaline. This is reflected by a significant increase in the sulfate conjugate of both of these compounds. The monoamine oxidase activity is decreased slightly throughout the collection periods. This is reflected by a decrease in the formation of 3-methoxy-4-hydroxymandelic acid following an injection of both noradrenaline and normetadrenaline.
Nucleic acid content of turkey heart with a note on hemodynamic findings
Authors: Sumner Robert G. , Hoyle Thomas C. , McIntosh Henry D. , Whalen Robert E.
Published: December 2017

In order to study the marked disparity in thickness of the left and right ventricular (LV and RV) walls of the turkey heart, DNA, RNA, and protein content of LV and RV myocardium were determined in fowl aged 4, 6, and 11 weeks and at maturity. DNA concentration in RV tissue was significantly greater than that in LV tissue in each bird and at each age. DNA concentration in both ventricles, moreover, decreased with increasing age. Protein concentration in both ventricles increased as did protein-to-DNA ratios. Although RNA concentration showed less consistent changes with age, the RNA-to-DNA ratio increased. It was concluded that the predominant cellular change with age was hypertrophy. In addition, electrocardiograms and hemodynamic data were obtained on birds in each group. Although pulmonary artery pressure is comparable to that in other laboratory animals, a markedly elevated systemic blood pressure develops between the ages of 6 and 11 weeks. The role of hypertension as a determinant of cellular size in the LV was not elucidated by this study.
Brain-stem inhibition of electrodermal (galvanic skin) activity
Authors: Glasser Richard L. , Perez-Reyes Mario , Tippett Joe W.
Published: December 2017

Spontaneous and evoked electrodermal potentials were recorded from the footpads of cats subjected to vagotomy, midmesencephalic decerebration, and serial transections of the central neuraxis from the intercollicular level to the uppermost cervical spinal segments. Eight animals were decerebellated while in the midmesencephalic condition. Electrodermal activity was profoundly depressed by midmesencephalic decerebration. Subsequent decerebellation and transections through the caudal half of the mesencephalon and the rostral third of the pons produced little alteration. However, serial transections through the middle and caudal thirds of the pons progressively enhanced electrodermal activity. Further augmentation was obtained following transection of the spinal cord. These data indicate that the brain stem contains an extensive electrodermal inhibitory system consisting of pontile and medullary components. Maximal suppression of electrodermal activity in the midmesencephalic animal requires the integrity of both components of this system. Distinguishing characteristics between the brain-stem electrodermal inhibitory system and the somatic reticular inhibitory system are discussed.
Canine gastric blood flow and its distribution
Authors: Delaney John P. , Grim Eugene
Published: December 2017

Total gastric blood flow in the dog as estimated by the K42 clearance technique agreed within 5% with measured total venous outflow. Extraction of the isotope by the stomach was found to be such that 30–60 sec following injection the organ contained a fraction of the injected dose that was the same as the fraction of the cardiac output that perfused the organ. By comparison with the radioactive microsphere method, the K42 clearance technique was also found to be reasonably accurate for determination of the distribution of the total flow within the organ. Mean total gastric blood flow in intact dogs, unoperated upon except for femoral arterial and venous catheterization, was 49 ml/min per organ or 0.54 ml/min per gram. This was distributed 80% to corpus and 20% to antrum. The corpus flow was partitioned among the mural tissues: mucosa 72%, submucosa 13%, and muscle serosa 15%.
Effects of exercise and administration of aspartic acid on blood ammonia in the rat
Authors: Barnes Richard H. , Labadan Beatriz Alcazar , Siyamoglu Bahriye , Bradfield Robert B.
Published: December 2017

The rise of blood ammonia following a short period of exercise can be partially prevented by the prior oral administration of either aspartic acid or the mixed potassium and magnesium salts of aspartic acid. These compounds will also prolong the time required for the rat to reach physical exhaustion due to forced swimming. As an extension of these observations, it has been found that daily feeding of ammonium carbonate over a 4-week period will also prevent the rise of blood ammonia due to exercise and will prolong exhaustion time of rats that are forced to swim. These same changes have been observed in rats that were exercised daily by short periods of forced swimming and, after 3 weeks of this type of physical training, were tested for blood ammonia response to exercise and time required for exhaustion. It is concluded that both daily ammonium carbonate feeding and training result in adaptation of enzymes in the ornithine cycle so as to increase the rate of blood ammonia removal.
Effect of hypoxia on pulmonary artery pressure of dogs
Authors: Wilcox Benson R. , Austen W. Gerald , Bender Harvey W.
Published: December 2017

The mechanism by which the pulmonary artery pressure rises in response to hypoxia has never been clearly demonstrated. This problem was reinvestigated in experiments utilizing separate pulmonary and systemic perfusion systems. These vascular beds were perfused in such a fashion that a change in pulmonary artery pressure could only result from changes in vasomotor tone. Alveolar-pulmonary vein hypoxia was usually associated with a slight fall in pulmonary artery pressure. Systemic hypoxia resulted in elevation of pulmonary arterial pressure in 10 of the 12 animals tested with a constant-flow and constant-pulmonary venous pressure. In addition, all animals with systemic desaturation showed an increased venous return. When the "cardiac output" (pump output) was increased to match this return, the elevation in pulmonary artery pressure increased. It was concluded that the pulmonary arterial pressure elevation seen with hypoxia is the result of active pulmonary vasoconstriction coupled with an increased pulmonary blood flow.
Pituitary-adrenal function during acute prochlorperazine administration in the dog
Authors: Cushman Paul , Hilton James G.
Published: December 2017

Increased plasma 17-OH corticosteroid concentrations, as compared to controls, were observed after 4, 6, and 8 hr of prochlorperazine infusions into normal anesthetized dogs. ACTH-like activity was detectable in plasmas obtained at the 8th hr in the prochlorperazine-treated animals, by a bio-assay procedure involving corticosteroid secretion rates by the isolated adrenal of hypophysectomized dogs. Methopyrapone infusions resulted in increased plasma 17-OH corticosteroid concentrations at the 6th and 8th hr. However, the combination of methopyrapone and prochlorperazine resulted in greater loss of the adrenal stimulatory effect than seen with either agent alone. Prompt increases in plasma 17-OH corticosteroid concentrations upon addition of ACTH to these combined infusions reflected normal secretory capacity of these adrenals. Prochlorperazine alone perfused into the isolated adrenal preparation was neither stimulatory nor inhibitory. The evidence suggests a complex action of prochlorperazine. First, intravenous administration of prochlorperazine results in ACTH release, readily detectable after 8 hr. Second, partial inhibition of ACTH production, as evoked by methopyrapone in the intact animal, possibly may occur at the hypothalamic level.
Liberation of antidiuretic hormone: location of ascending pathways
Authors: Mills Elliott , Wang S. C.
Published: December 2017

Water diuresis was established and maintained in dogs anesthetized with chloralose. Both ureters were cannulated and a continuous recording of urine flow obtained. Antidiuretic responses (equivalent to 5–10 mU total dose of arginine vasopressin iv) were obtained from stimulation of the central end of a vagus or ulnar nerve and from certain reactive areas in the medulla, pons, and midbrain. In the medulla, responses were frequently obtained from the area of the tractus solitarius and from many points in the lateral reticular formation. In the pons, responses were elicited from the medial portion of the central gray and from the lateral reticular formation. The area of the medial lemniscus was not responsive. At levels rostral to the inferior colliculus, the reactive area was limited to the area of the central tegmental tract and the periaqueductal gray. The evidence suggests that impulses from the visceral and somatic afferent systems mediating ADH release ascend through the brain stem over an extralemniscal pathway. The mammillary peduncle does not appear to be part of the ascending pathway mediating ADH release; rather, impulses may reach the hypothalamus through a relay in the thalamus as well as by relay over the periventricular system of Schütz.
Circulatory responses to hypocapnia in the anesthetized dog
Authors: Kontos Hermes A. , Mauck H. Page , Richardson David W. , Patterson John L.
Published: December 2017

The circulatory responses to hypocapnia were studied in 40 anesthetized dogs. Hypocapnia induced without a change in ventilation caused slight increase in limb vascular resistance in six dogs and decrease in one. Hypocapnia induced by hyperventilation caused increase in limb vascular resistance in six dogs and decrease in four. Following administration of phenoxybenzamine into the femoral artery, hypocapnia induced by either method invariably caused increase in limb vascular resistance (8 dogs). These results show that hypocapnia has a direct vasoconstrictor effect on limb blood vessels. In the intact limb this response may be opposed by vasodilator effects mediated through nerves. Hypocapnia induced without change in ventilation had no significant effect on cardiac output, systemic vascular resistance or arterial blood pressure (8 dogs). Hypocapnia induced by increased ventilation was associated with significant decreases in cardiac output and systemic arterial blood pressure and significant increase in systemic vascular resistance (9 dogs). These responses were probably related to the effects of increased intermittent positive pressure used to augment ventilation.
Intestinal distribution of intrinsic factor and vitamin B12 absorption
Authors: Okuda Kunio , Sasayama Katsumi
Published: December 2017

Evidence is presented that intrinsic-factor (IF) activity is present in the small intestine as far down as the ileal end. Physiologic doses of radioactive vitamin B12 without IF were applied directly into various levels of the intestine by surgical and other means in man and rats, and significant absorption was obtained from the small intestine. Absorption inhibition by ethylenediaminetetraacetate and its counteraction by Ca ion demonstrated that such absorption was dependent on IF action. The large intestine was shown to be incapable of physiologic absorption of vitamin B12, and IF was totally ineffective. It is proposed that physiologically, gastric IF descends with some activity in the small intestine, where more of the food vitamin B12 is liberated by digestion and subjected to IF.
Effect of xanthines and histamine on ion transport and respiration by frog gastric mucosa
Authors: Alonso Darwin , Harris John B.
Published: December 2017

In standard chloride solutions, methyl xanthines enhanced ion transport and oxygen consumption by frog gastric mucosa in vitro to a significantly greater extent than did histamine. Substituting glucuronate for chloride in the bathing solutions abolished ion transport, but left respiration unchanged. Caffeine and histamine had no effect on respiration in glucuronate solutions, but butyrate stimulated respiration to the same extent in chloride and glucuronate solutions. All of these effects appeared to be a function of the epithelial cells, since respiration by smooth muscle from the stomach was not affected by any of the compounds. It is postulated that the hydrogen ions of gastric secretion are derived from the dehydrogenation process during substrate oxidation. Following dehydrogenation, the methyl xanthines and histamine stimulate some step in the events that lead to the formation of hydrochloric acid. In the respiring, non-acid secreting mucosa, the hydrogen ions follow the usual intracellular pathways that lead to the formation of water.
Enzyme-induced rupture of rabbit Graafian follicle
Authors: Espey Lawrence L. , Lipner Harry
Published: December 2017

The mechanism of ovulation has been further examined by utilization of a model based on enzymically induced rupture of the follicle. One to two microliters of aqueous solutions of various proteolytic enzymes were injected into estrous-stage (fully developed with antrum—preovulatory) follicles on the surface of exteriorized rabbit ovaries maintained at body temperature. Preparations of bacterial collagenase or the proteases pronase and nagarse induced changes in the follicle similar to those seen during normal ovulation. One microliter of a 10% solution of collagenase was approximately the amount capable of inducing rupture. With this amount of collagenase the average time between injection and rupture was 10 min, with a range from 2 to 20 min. The pressure changes during induced rupture were comparable to those observed during coitally induced ovulation. The similarity between enzyme-induced rupture and coitally induced ovulation suggests that the structural changes preceding normal rupture of the wall of the Graafian follicle may be the consequence of proteolysis.
Renal ammonia release during ammonium chloride acidosis
Authors: Owen Edward E. , Robinson Roscoe R.
Published: December 2017

The effect of prolonged oral ammonium chloride administration on the simultaneous release of ammonia into urine and renal venous blood was examined in the dog. Quantitatively, chronic ammonium chloride acidosis was accompanied by an almost identical average elevation of both urine ammonia excretion and renal venous ammonia release. Although not definitive, the results are entirely consistent with the prevailing concept that ammonia enters urine and renal venous blood via a pH-dependent process of non-ionic diffusion.
Effect of external sodium on net potassium uptake by frog muscle
Authors: Armstrong W. McD.
Published: December 2017

When longitudinal strips of frog stomach muscle or frog sartorius muscles, previously depleted of K by overnight immersion in the cold in K-free Ringer solution containing 116 mEq Na/liter, were reimmersed at room temperature in solutions containing K, replacement of Na in the recovery fluid by Li or choline inhibited net K uptake by the fibers. Stomach muscles soaked overnight in Na-free solutions containing Li or choline lost K and most of their Na, the Na being replaced by Li and, inferentially, by choline. When these muscles were reimmersed in Na-Ringer solution they accumulated K from the medium. On reimmersion in Na-free Li or choline-Ringer solution no net K uptake occurred. Partial replacement of Li or choline by Na resulted in net K accumulation. Stomach muscles soaked in K-free Na-Ringer solution and subsequently transferred to Na-free solutions containing Cs and K did not accumulate K. Partial replacement of Cs by Na did not affect the inhibition of K uptake by Cs. K accumulation by frog stomach muscle was not affected by cyanide (2 mmoles/liter). These results are compatible with a specific stimulating effect of external Na on K accumulation in frog muscle.
Plasma clearance of cortisol and 11-deoxycortisol in dogs
Authors: Thomasson Bjorn , Steenburg Richard W.
Published: December 2017

The chromogenic properties of cortisol and 11-deoxycortisol in the Porter-Silber reaction are identical. Recoveries of these substances from plasma by the Silber-Porter technique are similar, hence the plasma 17-hydroxycorticosteroid concentration reflects the concentrations of 11-deoxycortisol or cortisol in a quantitatively similar manner. The disappearance of 17-hydroxycorticosteroids was determined after intravenous infusions of cortisol and 11-deoxycortisol in adrenalectomized dogs. The exponential disappearance of 11-deoxycortisol (T1/2, 87 min) was more rapid than that of cortisol (T1/2, 104 min). Although this small difference in the slopes is only questionably significant, the 17-hydroxycorticosteroid concentration at each interval after cortisol infusion was two to three times greater than after 11-deoxycortisol. This concentration difference was statistically significant ( P < 0.01) at all points. These data suggest that the distribution of injected 11-deoxycortisol is quite different from that of cortisol. As a result, the rate of adrenal corticogenesis is difficult to ascertain on the basis of plasma 17-hydroxycorticosteroid concentrations when, under the influence of Methopyrapone, the production of cortisol is replaced by that of 11-deoxycortisol.
Intrinsic factor-like activity in extracts of guinea pig intestine
Authors: Ukyo Shigeo , Cooper Bernard A.
Published: December 2017

Co57-labeled B12 tube fed to guinea pigs with normal human gastric juice has been found in both the supernatant and sediment of a saline extract of intestinal mucosa. The Co57-labeled material in the supernatant was excluded from Sephadex G-25, was not ultrafiltrable, and functioned as an intrinsic factor-B12-Co57 complex in an in vitro assay for intrinsic factor activity.
Effect of lipid absorption on glucose metabolism by slices of hamster small intestine
Authors: Holt Peter R. , Haessler Herbert A. , Isselbacher Kurt J.
Published: December 2017

Glucose utilization in vitro by hamster jejunal slices was shown to be enhanced during the absorption of free fatty acids and this effect was most striking with oleic acid. Glucose-C14 conversion to glyceride-glycerol was proportional to lipid concentration but, in addition, there was distinct increase in glucose oxidation and lactic acid-C14 formation. In striking contrast to the effects of fatty acids, monoglyceride absorption was associated with little change in glucose utilization, and there was actually a reduction in glucose-C14 appearance in glyceride-glycerol. The data suggest that absorption of free fatty acids and their esterification with L-α-glycerophosphate is associated with a stimulus for glucose metabolism. However the stimulation of glucose metabolism is in excess of that required for L-α-glycerophosphate formation. The reasons for this are not clear at present. The effects observed with monoglycerides suggest predominant esterification with tissue free fatty acids by monoglyceride acylase in preference to hydrolysis intracellularly by monoglyceride lipase.
Plasma lipids in ascorbic acid-deficient rhesus monkeys
Authors: Banerjee Sachchidananda , Bandyopadhyay Asok
Published: December 2017

The different fractions of plasma lipids were studied in scorbutic rhesus monkeys. Plasma insulin-like activity, glucose tolerance, and plasma free fatty acid (FFA) response to glucose load were also determined in these animals. Scorbutic monkeys showed decreased plasma concentrations of total cholesterol, ß-lipoprotein cholesterol and phospholipids and decreased percent of total lipoprotein in α-fraction; increased levels of plasma triglycerides and FFA and increased percent of total lipoprotein in ß-fraction; diminished plasma insulin-like activity; diminished glucose tolerance; and absence of the normal fall in plasma FFA in response to glucose load. All these changes were reversed when scorbutic monkeys recovered after supplementation of the diet with ascorbic acid, except that total plasma cholesterol and ß-lipoprotein cholesterol remained low. Scorbutic monkeys seemed to suffer from hypoinsulinism.
Lateral hypothalamic aphagia: motor failure or motivational deficit?
Authors: Rodgers Willard L. , Epstein Alan N. , Teitelbaum Philip
Published: December 2017

Recovery of feeding was studied in rats with lateral hypothalamic lesions. The animals were given the choice of feeding themselves by mouth or by pressing a bar for injections of food into their own stomachs. Foods of high palatability were offered for oral feeding. A method of intragastric self-injection was employed that permits the animal to eat without making the feeding movements and without tasting or smelling the food. The lesions typically produced a complete failure to eat for from 1 to 15 days. During the period of complete aphagia all animals tested made the movements of feeding when food was put in their mouths. In all cases, feeding by mouth returned before bar pressing and intragastric feeding. A recent conflicting experiment is discussed. It is concluded that rats with lateral hypothalamic aphagia can eat but do not because they are not hungry.
Vitamin D and permeability of intestinal mucosa to calcium
Authors: Harrison Harold E. , Harrison Helen C.
Published: December 2017

The role of the permeability of intestinal mucosa to calcium was determined in rats by comparison of calcium transport in vitro across the wall of everted intestinal loops from which the mucosal epithelium was removed and of loops with intact epithelium. Energy-dependent transport systems were inhibited by incubation at 5 C or by addition of N-ethyl maleimide to the medium. The experiments were designed to measure calcium transport along a concentration gradient between mucosal and serosal surfaces at varying concentrations of calcium in the mucosal solution. The results indicate that the intact intestinal mucosa presents a diffusion barrier to calcium and that this diffusion barrier is lessened by vitamin D treatment of the animal from which the intestine is obtained.
Relationship between sodium and glucose transport in canine jejunum
Authors: Nelson Ralph A. , Beargie Richard J.
Published: December 2017

The effect of varying rates of insorption and exsorption of sodium on glucose absorption in the jejunum was studied in 19 dogs. In the first part of the study, glucose absorption was followed in two solutions, similar in composition except for sodium concentrations. In one solution, Na concentration was 145 mEq/liter and in the other, 22 mEq/liter. Absorption tests were done before, during, and after periods of reduced gut blood flow. When blood flow was reduced, proportionate decreases were observed in all measurements. The effects of reducing blood flow complicated the analysis, yet a suggestion of a relationship between glucose absorption and sodium exsorption was noted. Reduced blood flow also produced or enhanced enterosorption of potassium. In the second portion of the study, blood flow to the gut was maintained constant while sodium exsorption was varied by decreasing the concentration of sodium in the plasma It was found that glucose absorption declined when sodium exsorption declined. Approximately 107 µmoles of glucose were absorbed per milliequivalent of sodium exsorbed. It was concluded that the level of plasma sodium and the amount of sodium exsorbed are factors involved in glucose absorption.
Influence of atropine on heart rates of rats
Authors: Tipton Charles M. , Taylor Bryce
Published: December 2017

Resting heart rates were obtained from unanesthetized and unrestrained male rats before and after an intraperitoneal injection of atropine sulfate (1 mg/kg). Recordings were made at 10-min intervals for a duration of 90 min. Half of the rats had been trained and were capable of running at treadmill speeds of 1.25 miles/hr for 1 hr/day. The results showed that the trained group had a significantly lower preinjection heart rate than the nontrained group and that atropine caused a greater cardiac acceleration in nontrained rats than in trained rats. The group differences were statistically significant. These results were explained by the hypothesis that trained populations have available more nonneural acetylcholine to compete against the atropine for the receptor sites.
Transmission of electrical activity through the gastroduodenal junction
Authors: Bortoff Alex , Weg Noah
Published: December 2017

The electrical and mechanical activities of the gastroduodenal junction were studied in isolated cat preparations, using the pressure-electrode technique. The spontaneous electrical activity of the pyloric antrum consists of periodic depolarizations, the configuration of which is somewhat more complex than that of comparable potentials recorded from the longitudinal muscle layer of the small intestine. Like their intestinal counterparts these antral slow waves may be associated with spike potentials which are thought to initiate contractions. The electrical activity at the gastroduodenal junction consists of a combination of antral and duodenal slow waves, sometimes accompanied by spike potentials. In the proximal duodenum, antral slow waves are represented by periodic depolarizations which may be associated with spike potentials followed by contractions. Because of the extension of the antral slow waves into the proximal duodenum, contractions initiated in the antrum may also extend into the proximal duodenum. It is concluded that the gastroduodenal junction is a transition zone, coordinating the electrical and corresponding mechanical activities of the antrum and proximal duodenum.
Conjugation and excretion of phenoltetrabromphthalein mono-, di-, and tetrasulfonates
Authors: Javitt Norman B.
Published: December 2017

Phenoltetrabromphthalein monosulfonate and tetrasulfonate were administered to rats. The disappearance from plasma and excretion into bile was determined and compared to sulfobromophthalein. Spectrophotometric, paper-chromatographic, and electrophoretic methods of analysis were used for detection of the compounds and their derivatives. The monosulfonate disappeared rapidly from plasma and was excreted in bile as glutathione and glutathione-glucuronide derivatives. The tetrasulfonate disappeared slowly from plasma and was excreted in bile apparently unchanged. The tetrasulfonate reacted chemically with glutathione but the reaction was not enzymatically catalyzed in vitro. It is concluded that the number of sulfonate groups on the phenoltetrabromphthalein molecule are important determinants of hepatic conjugation and excretion.
Competition for intestinal transport among five neutral amino acids
Authors: Matthews D. M. , Laster Leonard
Published: December 2017

Rates of transport against a concentration gradient by everted segments of hamster small intestine were determined for increasing concentrations of glycine and l-alanine, each in the presence of 2 mm l-leucine. By plotting the data according to Lineweaver and Burk the results were compared to those obtained in similar experiments performed in the absence of l-leucine. The results suggest that inhibition of glycine or l-alanine transport by l-leucine is competitive. Values for Kt, the amino acid concentration at which half-maximal transport is observed, were used to calculate predicted inhibitory effects among the several amino acids studied. The inhibitory effects were determined experimentally and were found to be in approximate agreement with the predicted values, suggesting that the mutual transport inhibitions among the monoaminomonocarboxylic acids are competitive, and that all the amino acids studied share the same transport mechanism.
Effects of Na and Ca on the generation and conduction of excitation in the ureter
Authors: Kobayashi Makoto
Published: December 2017

Effects of Na+ and Ca++ on the generation and the conduction of excitation were studied by using a pelvis ureter specimen of cat. Action potentials were recorded simultaneously from the renal pelvis and the various regions of the ureter, and they were used to indicate the arrival of excitation. In Na+-deficient solutions, both the frequency of excitation and the conduction velocity decreased gradually, and finally a conduction block occurred at the border between the renal pelvis and ureter. In Na+-free solution spontaneous excitation was not observed in most cases. When excess Ca++ was added to Na+-free solution, spontaneous excitation was restored, but the concentration of Ca++ necessary for the restoration had to be at least twice that in normal Ringer-Krebs solution. The difference between the ureter and taenia coli was considered with regard to the role that Na+ and Ca++ play in the generation of spontaneous excitation.
Estimation of extracellular spaces of smooth muscle using different-sized molecules
Authors: Barr Lloyd , Malvin Richard L.
Published: December 2017

The apparent fraction of tissue water available as solvent was determined for a number of test substances: urea, arabinose, mannitol, sucrose, raffinose, inulin, and radioiodinated serum albumin. The apparent extracellular spaces decrease with increasing molecular size. Urea seems to come to concentration equilibrium in all tissue water. Arabinose and mannitol values are close together at about 70% tissue water. Similarly sucrose, raffinose, and inulin values cluster at about 48% tissue water, while RISA can reach only about 20%. The amounts of sodium, potassium, and chloride in canine intestinal smooth muscle are similar to values given for other smooth muscle. Intracellular ion concentrations similar to those of other tissues can be calculated if the true extracellular space is between that measured by RISA and sucrose.
Taste receptors and sialadenotrophic action of proteolytic enzymes in rats
Authors: Wells Herbert , Peronace Angela A. V. , Stark Lawrence W.
Published: December 2017

Dietary administration of proteolytic enzymes such as chymotrypsin, trypsin, bacterial protease, or papain resulted in a marked increase in the weight of the submandibular salivary glands. After sympathectomy, but not parasympathectomy, the response of the glands to papain was partially reduced. After complete autonomic denervation the papain effect was absent completely. The enzymes retained their sialadenotrophic action when administered as intra-oral drops, but were not effective if administered by stomach tube. Although the response to papain was completely absent after section of the glossopharyngeal nerves, section of the lingual nerves did not affect the response. The sialadenotrophic effect of repeated amputation of lower incisor teeth was not altered by prior section of the glossopharyngeal or lingual nerves. The results suggest that the sialadenotrophic action of proteolytic enzymes depends on a neural reflex arc. The afferent arm consists of the taste receptors innervated by the glossopharyngeal nerves, while the efferent arm is composed of both branches of the autonomic nervous supply to the glands.
Intrarenal distribution of blood flow
Authors: Pilkington Lou Ann , Binder R. , de Haas J. C. M. , Pitts Robert F.
Published: December 2017

Clearances and extractions of para-aminohippurate were measured in normal dogs to investigate a proposal by Reubi for the approximation of the distribution of intrarenal plasma flow. The proposal equates the cortical plasma flow to the clearance of PAH, assuming that PAH is 100% extracted from the cortical flow. Medullary plasma flow is equal to the difference between total renal plasma flow and cortical plasma flow. Our evidence is consonant with this view. The distribution of plasma flow was so calculated during the intravenous infusion of 20% mannitol and during the infusion of acetylcholine or norepinephrine into the left renal artery. Mannitol and acetylcholine (50–80 µmoles/min) increased both cortical and medullary plasma flows and the total renal plasma flow. Medullary flow, however, increased proportionately more than cortical flow. Norepinephrine (38–9.0 µmoles/min) decreased cortical plasma flow and total renal plasma flow equally. Medullary flow did not change significantly.
Potassium and sodium excretion and potassium homeostasis during acute hypokalemia
Authors: Siegel Robert R. , Lotspeich William D.
Published: December 2017

Decreased potassium and increased sodium excretion were observed in dogs acutely potassium-depleted by hemodialysis. Potassium excretion at constant blood pH varied directly with plasma [K+]. When filtered Na load and urine flow were constant during K+ depletion, increase in Na excretion was equivalent to decrease in K+ excretion, suggesting close coupling between transtubular movements of the two ions. Large changes in plasma [K+] (30%) and K+ excretion (50%) were produced with removal of a relatively small amount (estimated 3%) of total body K+. Plasma [K+] decrease during depletion was rapidly decelerated by movement of intracellular K+ into the extracellular fluid (ECF). When ECF [K+] stabilized, further decrease in K+ excretion ceased despite continued reduction of total body K+. It appears: 1) that tubular secretion of K+ is directly and rapidly responsive to reduction in ECF [K+]; 2) that low ECF [K+] may simultaneously impair contraluminal K+ uptake and Na extrusion, reducing K+ excretion and Na reabsorption during acute hypokalemia. Stoichiometry of changes suggests a 1:1 coupling between K+ secretion and moiety of Na reabsorption in the distal nephron.
Effects of hypoxia on in vivo glycine-C14 incorporation into pancreatic cell proteins
Authors: Turner M. Don , Turner Anne C.
Published: December 2017

The effects of graded hypoxia on glycine-C14 incorporation into subcellular components were measured in the intact mammal. Groups of three fasted male rats were injected intraperitoneally with 5 µc of glycine-2-C14 and sacrificed at 5 (or 10), 15, 20, 30, and 45 min by decapitation. In one experimental series the environmental pO2 was maintained at 35 mm Hg for 2 hr before injection and throughout the experiment. In three other experimental series, the pO2 in the sealed chamber was maintained at 58, 48, and 38 mm Hg for 45 min before injection and for the duration of the experiment. The whole pancreases were rapidly removed, cooled, homogenized, and pooled before separation of cell fractions by ultracentrifugation. The specific activities (counts/min per µg of amino acid or protein N) were obtained for plasma and supernatant fraction ("cell sap") amino acids and for the purified proteins of zymogen granule, mitochondrial, microsomal, and cell sap fractions from micro-Kjeldahl analyses and liquid-scintillation counting. No detectable changes were found in the turnover of plasma amino acids during graded hypoxia. Amino acid incorporation into the proteins of all cell fractions was depressed stepwise with increasing degrees of hypoxia.
Identity of pulmonary artery pressure and lobeline-induced ventilatory reflex
Authors: Bevan John A. , Kinnison Gerald L.
Published: December 2017

Reflex ventilatory changes following pulmonary artery pressure reduction have been compared in the α-chloralose-anesthetized intact cat to those following the intravenous injection of lobeline, phenyldiguanide, and veratridine. These drugs stimulate different groups of sensory neurons in the pulmonary vascular bed. The reflex changes initiated by pulmonary artery pressure reduction and by small doses of lobeline are predominantly ventilatory, whereas those consequent on phenyldiguanide and veratridine are not. Using specific reflex blocking procedures, it was shown that although definite and consistent separation of the responses to the three drugs could be obtained, the responses to pulmonary artery pressure reduction and lobeline could not be differentiated. It is concluded that pulmonary artery pressure fall and lobeline probably act on the same reflex, which, since it is known that the reflexogenic lobeline-sensitive zone lies in the extrapleural pulmonary arteries, must be a ventilation-regulating reflex originating from a pressure-sensitive zone in the region of the pulmonary artery bifurcation.
Salivary secretion in the rat after ouabain
Authors: Schneyer L. H. , Schneyer C. A.
Published: December 2017

Ouabain was injected intravenously (0.5 mg/kg) or intraperitoneally into anesthetized rats. After 50 min, pilocarpine was administered and saliva was collected from submaxillary or parotid glands. [K] was found to be elevated in both secretions, while [Na] was reduced in parotid saliva. Changes in salivary flow were not the major cause of the alterations in electrolytes. Analyses of gland tissues after injection of ouabain showed [K] and [Na] to be essentially unaffected in whole tissue or cell water. Blood flow to the glands also was apparently unchanged. However, with incubated submaxillary slices, 5 x 10–4 m ouabain inhibited accumulation of K, and this inhibition could be prevented by raising [K] in the incubation medium. These effects were evaluated in relation to the current concept that salivary K is derived largely from intracellular stores of the ion, with ensuing secondary equilibration. It was concluded that the effects of ouabain are consistent with this model, and that, in vivo, ouabain probably inhibited reabsorption of K after its initial release from secretory cells.
Acid secretion, potential, and resistance of frog stomach in K+-free solutions
Authors: Davis T. L. , Rutledge J. R. , Keesee D. C. , Bajandas F. J. , Rehm W. S.
Published: December 2017

The removal of K+ from the fluids bathing the in vitro frog gastric mucosa results in a decrease of the H+ secretory rate to zero, a marked increase in electrical resistance, a transient increase in potential difference (PD), and relatively little change in the K+ content of the mucosa. The effects of K+ removal are reversed by adding K+ either to the nutrient fluid (4 mm) or to the secretory fluid (104 mm). They are not reversed by voltage clamping (nutrient positive). Following the cessation of H+ secretion, the PD gradually decreases to a level that is low but still greater than zero. The PD under these conditions can be reversibly reduced to about zero by anoxia. It is concluded that the presence of K+ in certain regions of the mucosa is necessary for the functioning of the H+ and Cl– mechanisms.
Oxygen uptake and tetrazolium reduction during skin cycle of the mouse
Authors: Dushoff Ira M. , Payne John , Hershey Falls B. , Donaldson Robert C.
Published: December 2017

Quantitative measurements of oxygen consumption and triphenyl tetrazolium chloride reduction by intact skin were made during various stages of the skin cycle of the mouse. Values are highest during early anagen, when growth is most rapid: Qo2 is 2.47 ± 0.10 (mean ± se) and TTC is 537 ± 24.6. In late anagen the activities decrease 40–50%: Qo2 is 1.24 ± 0.10 and TTC is 315 ± 20.8. There is a close relationship between tetrazolium reduction and oxygen consumption during all phases of the growth cycle of mouse skin. The coefficient of regression of TTC on Qo2 is 163.2 ( P < .001).