bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of growth hormone on pyruvic acid metabolism
Authors: Weil Rudolf , Altszuler Norman , Kessler Jacques
Published: December 2017

The effect of bovine growth hormone on pyruvic acid metabolism was studied in normal dogs. The intravenous infusion of glucose (0.5 g/kg/30 min) into normal dogs results in a rise in the blood pyruvic acid concentration, followed by a return to control levels in 90 minutes. A growth hormone regimen (1 mg/kg/day) for 3–5 days produces an elevation in the pyruvic acid levels in the 17–20-hr-fasted dog. Administration of glucose at this time results in much higher blood pyruvate levels and a delayed return to control levels. The removal of glucose from the plasma is not impaired by this growth hormone regimen. The possibility that these findings reflect an inhibitory effect of growth hormone on pyruvic acid metabolism was investigated by determining the rate of removal of pyruvic acid from the blood after infusion of sodium pyruvate (0.3 g/kg/15 min) in normal dogs in the untreated state and while on a growth hormone regimen. The decline in pyruvate concentration from peak levels attained at the end of the infusion is markedly prolonged in the growth-hormone-treated animals, indicating impairment of pyruvate utilization. It is suggested that this action of growth hormone to impede removal of pyruvic acid from the blood is related to the fat-mobilizing effect of growth hormone.
Growth hormone and mammary gland lobule-alveolar development
Authors: Moon Richard C.
Published: December 2017

The effect of growth hormone on mammary gland lobule-alveolar growth in the ovariectomized rat was studied using deoxyribonucleic acid (DNA) of the abdominal-inguinal glands as an index of the degree of cellular proliferation. The administration of 1 mg growth hormone in combination with 2 µg estradiol benzoate for 19 days resulted in alveolar formation and an increase in mammary DNA content above that resulting from injections of either hormone alone. The mean DNA concentration of glands of rats treated with 2 µg estradiol, 6 mg progesterone, 3 µg/100 g l-thyroxine, and 0.5, 1.0, 1.5, and 2.0 mg growth hormone was significantly greater than that of animals receiving only the estradiol, progesterone, and thyroxine. The increase in the mean DNA content was due to a shift in the range of values to a higher plane and did not result from an elevated DNA in only a few animals. It is suggested that the administration of growth hormone during the growth phase of the mammary gland may have a beneficial effect on the subsequent lactation.
Relationship of salivary flow and pressure in dog submaxillary and parotid glands
Authors: Langley L. L. , Brown R. S.
Published: December 2017

The maximal secretion pressure in both the submaxillary and parotid gland varies directly with the rate of flow. At high rates (1 ml/min) of flow the pressure in the submaxillary gland is significantly higher than that in the parotid. At these flow rates the secretion pressure in both glands is higher than the capillary blood pressure.
Ventricular fibrillation threshold
Authors: vanTyn Robert A. , MacLean Lloyd D.
Published: December 2017

The use of single rectangular stimuli, applied directly to the heart surface, has been confirmed as a reliable method for measurement of the ventricular fibrillation threshold (VFT). The following factors which influence reproducibility were investigated: 1) spatial separation of bipolar electrodes, 2) interval between stimuli, and 3) anatomical position of electrodes on the heart. With bipolar electrodes placed 10–30 mm apart and an interval of 10–15 cycles between stimuli the VFT was remarkably constant for any single dog. An interelectrode separation of 2–4 mm or the placement of electrodes in a coagulated area of epicardium produced high, widely variable, and at times unobtainable thresholds believed due to short circuiting of the current delivered. Thresholds determined with stimuli 3–4 beats apart were significantly lower than when stimuli were delivered 10–15 beats apart. The VFT was significantly higher at the base than at the apex of the left ventricle. Investigations which measure the effect of a given influence on the VFT should control the factors studied here.
P32 uptake in DNA nucleotides after partial hepatectomy and after unilateral nephrectomy
Authors: Simpson David P.
Published: December 2017

Deoxyribonucleic acid (DNA) synthesis as reflected in the specific activity of DNA nucleotides 12 hr after intraperitoneal injection of P32 has been compared after partial hepatectomy and after unilateral nephrectomy. Thirty-six hours after partial hepatectomy, a maximum uptake 11-fold greater than in controls was found. The maximum after unilateral nephrectomy occurred 48 hr after operation and was twofold greater than in controls. Subsequent to these maxima, P32 uptake declined after both operations to a minimum eight days postoperatively which was followed by a second rise on the 9th day. These data support the concept that similar basic mechanisms regulate growth and cell division after the two types of operation. In another experiment, P32 uptake in kidney DNA nucleotides showed no increase after partial hepatectomy; this lends weight to the hypothesis that the mitosis-stimulating substances which appear in the serum after partial hepatectomy and after unilateral nephrectomy are organ specific.
Angiotensin blood levels in dogs with experimental renal hypertension
Authors: Scornik Oscar A. , Paladini Alejandro C.
Published: December 2017

A modified method for estimation of angiotensin in blood is described and its reliability is discussed. Angiotensin blood levels (ABL) were determined in normal dogs. After an intravenous injection of different doses of renin, an excellent correlation was obtained between blood pressure increases and ABL. After severe clamping of the renal arteries in 20 dogs, inconsistent increases in ABL were detected. In several of these animals distinct increases in blood pressure were seen with normal or undetectable ABL. Eight chronic renal hypertensive dogs repeatedly showed normal ABL. It appears, therefore, that an increase in ABL is not essential for the production of acute malignant or chronic benign renal hypertension.
Movement of microspheres through the pulmonary circuit
Authors: Ring Gordon C. , Kurbatov T. , Smith W.
Published: December 2017

Microspheres of styrene divinyl benzene varying in size from about 1 µ to 16 µ have been injected into the pulmonary artery of dogs. The proportion of the spheres of various sizes which reach the systemic circuit has been determined. The spheres in the groups less than 5 µ in diameter which pass through the pulmonary circuit are diminished when norepinephrine or serotonin is infused but are not affected by the infusion of acetylcholine or inhalation of carbon dioxide in oxygen. Spheres of sizes larger than 5 µ pass through the pulmonary circuit in larger proportions when CO2 is inhaled or acetylcholine is infused but are unaffected by norepinephrine and reduced by infusion of serotonin. The central volume is usually increased in dogs given serotonin but is unchanged during inhalation of CO2.
Capillary pressure and distribution of vascular resistance in isolated lung
Authors: Agostoni Emilio , Piiper Johannes
Published: December 2017

Isolated lobes of dogs' lungs were perfused with constant nonpulsatile blood flow and expanded by negative external pressure. The pressure under which Ringer solution was absorbed through the visceral pleura was measured by an osmometric method. From this pressure and the plasma colloid osmotic pressure, the pressure in the subpleural capillaries was calculated. The average value of the latter was 8.8 mm Hg when the pulmonary artery and vein pressures were 13.4 and 1.8 mm Hg, respectively. Assuming that the pressure in the intrapulmonary capillaries is similar to that in the subpleural capillaries, the vascular resistance on the arterial and venous side of the effective midpoint of pulmonary capillaries could be calculated. The average vascular resistance on the venous side was found to be 60% of the total intrapulmonary vascular resistance. Notwithstanding the limitations of the method this result suggests that in the pulmonary vascular bed the resistance on the arterial side and that on the venous side of the effective midpoint of capillaries are similar.
Free water excretion in normal dogs
Authors: Becker E. Lovell , Ginn H. Earl
Published: December 2017

Free water excretion (Chh2o = V - Cosm) was studied in unanesthetized dogs. This parameter of urine dilution was defined by superimposing an osmotic diuresis upon a water diuresis. Sodium sulfate (1.5%) gave the smallest free water clearance and sodium chloride (0.95%) the greatest, urea (1.65%) and mannitol (5.0%) being intermediary in their effects. Observed free water clearances were never maximal and, when plotted as Cosm vs. V, gave a slope of less than one. Two mercurial diuretics, meralluride and mercaptomerin, gave intermediary values for free water. Meralluride caused an early increase in free water clearance because of the theophylline incorporated in the compound. Later results were similar to those with mercaptomerin, both compounds producing free water clearances approaching a maximal rate.
Effects of stretch on tension development in frog atrium
Authors: Kahn Arthur J.
Published: December 2017

Initial tension, isometric contractile tension, and the first derivative of the contractile response were recorded from the atrial wall of frog hearts. These hearts were stretched progressively from 0 to 25 g of initial tension at 25 C. Maximum peak isometric tension, maximum rate of tension development, and maximum rate of relaxation were attained at the relatively low stretching force of 2 g and at a 50% increase in length. Peak contractile tension remained near maximum under high initial tension, but the maximum rates of contraction and relaxation were markedly decreased. Stress relaxation was apparent in all preparations at all levels of initial tension. It appears to represent an alteration of the internal tension mechanism different from the alteration which accompanies the increase or decrease of the stretching force.
Serum glycoproteins in growing pups
Authors: Sirek Otakar V. , Sirek Anna
Published: December 2017

Total protein-bound hexose, hexosamine, and sialic acid were determined in sera of six littermate mongrel pups at monthly intervals from the 4th day after birth up to the age of 7 months. The concentration of the individual constituents fluctuated considerably from month to month, but the values showed neither a definite trend nor a relationship to weight gain. When the carbohydrate moiety was expressed as percentage of total serum protein concentration, the values were high in newborn pups and diminished after the 1st month of life. This was due to a rise in the concentration of total serum protein, brought about by an increase of the albumin fraction which is low in carbohydrate.
Molecular features of sulfonamide transport in renal excretory processes
Authors: Despopoulos Agamemnon , Callahan Paul X.
Published: December 2017

Renal tubular excretory transport of selected sulfonamides is assumed to require a physicochemical interaction between the substrate and a postulated intracellular receptor molecule. It is proposed that substrate specificity in this transport system depends on the presence of the intramolecular sequence, (See PDF for Equation), in the sulfonamide. Reactivity of this group requires ionization at N, localization of the net negative charge at N, and electronegativity at each oxygen sufficient for the formation of hydrogen bonds. Presence of these three features in favorable combination permits transport. A three-point contact with the receptor can be described involving the anionic locus and both oxygens of the substrate. These proposals are supported by analysis of the physicochemical, biochemical, and physiological behavior of 52 sulfonamides both in surviving rabbit renal cortical slices (original observations) and in intact mongrel dogs (survey of representative published reports). Although transport of sulfonamides is treated as an independent biochemical mechanism, its relation to the renal hippurate transport system is recognized and similar responses of both classes of substrates to probenecid or to acetate are demonstrated experimentally.
Effect of ouabain on hyperthermic contracture of cat papillary muscle
Authors: Bassett Arthur L. , Hoffman Brian F.
Published: December 2017

Isolated cat papillary muscles were used to demonstrate the effects of temperatures up to 48 C on resting length and amplitude of isotonic contraction. Progressive heating caused an initial increase and then a marked decrease in resting length; the shortening was irreversible in most instances. Progressive heating caused a decrease and then an increase in amplitude of contraction. Maintained high temperature caused a subsequent decrease in contraction. The permanence of these changes depended on the maximum temperature reached and the duration of exposure. Ouabain and epinephrine failed to influence the contracture caused by high temperature.
Acid secretion, resistance, short-circuit current, and voltage-clamping in frog's stomach
Authors: Rehm Warren S.
Published: December 2017

Certain findings seemed to invalidate the author's separate site theory of HCl formation (separate H+ and Cl– ion electrogenic mechanisms). These findings are analyzed and further pertinent experimental data on the frog's stomach are presented. With an in vitro chamber method it was found that the onset of secretion (histamine stimulation) resulted in a sustained decrease in transmucosal resistance and a small initial increase in potential difference (PD) followed by a larger decrease. The ratio PD/resistance (the predicted short-circuit current, Isc) initially increased and then decreased. During short-circuiting, the onset of secretion resulted in the predicted changes in Isc. Following the establishment of secretion, changes in the H+ ion secretory rate frequently occurred without significant changes in Isc. Thiocyanate inhibition resulted in a transient increase in Isc and a sustained increase in both the PD and resistance. Clamping of the voltage across the mucosa at negative levels (nutrient negative) reversibly decreased the H+ ion rate. The average voltage necessary to reduce the H+ ion rate to zero was –140 mv. With a single loop equivalent circuit the average EMF of the H+ ion mechanism on the basis of the voltage-clamping experiments is 140 mv. Findings are explained by the separate site theory with the assumption of cytoplasmic biochemical coupling.
Rates of insorption of sodium and potassium from upper small bowel of rats
Authors: Moll Johann C. , Code Charles F.
Published: December 2017

Rates of insorption of radiosodium and radiopotassium from the unobstructed small bowel of rats were determined and compared with those obtained by others in healthy humans. Insorption of the isotopes under study was estimated by integration of their rates of appearance in the blood after placement in the small bowel and their rates of disappearance from blood after injection into the circulation. The rates of disappearance from arterial blood were determined during separate tests. They followed an exponential pattern similar though not identical with that reported from other species by other investigators. Radiosodium was insorbed more rapidly than radiopotassium. Mean values indicated that 50% of administered radiosodium was insorbed within 6–7 min, whereas 26–27 min were required for insorption of 50% of the radiopotassium. The rate constant during insorption of the first 76% of the Na22 was 10.8% per min and that for insorption of 58% of the K42 was 2.7% per min.
Effect of bile salt on pancreatic secretion of the dog
Authors: Kuroyanagi Y. , Chiles T. , Necheles H.
Published: December 2017

In the dog, secretion of the resting pancreas is affected little if at all by sodium dehydrocholate. On the other hand, secretin-stimulated pancreatic secretion is increased greatly by this bile salt; double vagotomy did not change this effect. The stimulating effect of the bile salt on secretin-stimulated pancreatic secretion was diminished greatly when both substances were mixed and administered immediately. There is a difference between effects of different brands of sodium dehydrocholate on the stimulated secretion of the dog's pancreas.
Hyperglycemic effect of glucosamine
Authors: Coulson Roland A. , Hernandez Thomas
Published: December 2017

The injection of large amounts of glucosamine into either alligators or rats increased the plasma glucose level to a height as great as that found in severe diabetes. Galactosamine and N-acetylglucosamine were inactive in this respect. Since glucosamine was not found to increase plasma lactic acid in either the alligator or rat or to decrease liver glycogen in the rat, it did not appear to function as a glycogenolytic agent. The injection of glucose combined with amounts of glucosamine which were too small to cause hyperglycemia in either animal led to the development of a very much more marked hyperglycemia than when glucose alone was injected. The evidence indicated that glucosamine inhibited glucose utilization and hence it could be considered to be diabetogenic. Neither glucosamine nor galactosamine were utilized for energy to any great extent and both were excreted in the urine of the two species as rapidly as thiosulfate, an inert compound known to be eliminated at renal filtration rate. Glucosamine and galactosamine in very small doses constricted the pupils of the eyes of the alligator. This miotic response and the glucosamine-induced hyperglycemia were decreased by insulin injections. Insulin hastened the disappearance of glucosamine from the plasma of the alligator.
Further evidence favoring a cardiac mechanism in irreversible hemorrhagic shock
Authors: Crowell Jack W. , Guyton Arthur C.
Published: December 2017

Cardiac output curves of normal dogs and dogs in various stages of hemorrhagic shock were determined with devices for continuous recording of cardiac output and atrial pressures to feed an X-Y recorder. Normal cardiac output curves were recorded during the early stages of shock but, after the animal had developed irreversible shock, a cardiac output curve indicative of cardiac failure was always recorded. As the irreversible shock progressed, successive cardiac output curves indicated progressive failure of the heart. A special feature of these experiments was that by increasing or decreasing the blood volume the cardiac output could be held constant. When the cardiac output was held constant, both the right and left atrial pressures slowly rose to extremely high values as shock progressed, and after a time the heart was unable to maintain normal output at even extremely high atrial pressures. The evidence is entirely consistent with the idea that the irreversible stage in hemorrhagic shock is caused by rapid progressive cardiac failure.
Renal response to measured blood volume expansion in differently hydrated dogs
Authors: Sonnenberg H. , Pearce J. W.
Published: December 2017

Infusion of artificial blood in anesthetized dogs produced expansion of intravascular and extravascular volumes, uncomplicated by changes in osmotic pressure or evidence of histamine release. The resulting diuresis and natriuresis was not accounted for by observed effects of exchange of circulating blood for infusate. The stimulus to the renal response after infusion must then have included the parameter of extracellular volume. The diuresis could not be explained as the result of measured alterations in renal hemodynamics, but the findings do not allow distinction between hormonal or other influences on tubular function. In animals prehydrated with saline, the diuretic and natriuretic responses to infusion were significantly greater than in normally hydrated dogs, whereas in dehydrated dogs the responses were significantly smaller. In these three groups the infusions produced comparable initial measured increases in intravascular volume. It is proposed that the renal regulation of extracellular fluid volume in the dog is determined by graded potentiation by the existing extravascular volume of the response to intravascular expansion.
Physiological effects of thermode and microwave stimulation of peripheral nerves
Authors: McAfee Robert D.
Published: December 2017

Physiological effects produced in cats, dogs, rabbits, and rats by microwave irradiation (3-cm radar and 12.2-cm Microtherm) are duplicated in these animals by heating peripheral nerves with a warm-water or resistance-wire thermode. Identical effects occur when a temperature ranging between 45–47 C is attained by either of these means at a treated peripheral nerve or within tissue rich in peripheral nerve fibers. The response elicited by thermode or microwave stimulation includes arousal reactions, blood pressure and vascular responses, and signs of neurohumoral activity. We have demonstrated that the physiological effect of microwave radiation is a result of thermal stimulation of peripheral nerves which occurs independently of a significant increase in skin temperature or of total body heating.
Metabolic rate and animal size correlated with decompression sickness
Authors: Kindwall Eric P.
Published: December 2017

A number of small animals, rats, guinea pigs, rabbits, and cats were exposed to high ambient pressure for long periods of time and rapidly decompressed. They were found not to suffer from clinical "bends" except when decompressed almost explosively. Usually they did not suffer joint symptoms, delayed shock, or other disabling or permanent sequellae. Nitrogen saturation-desaturation curves based on the small animals' metabolic rate per kilogram weight were derived. A number of small animal dives were analyzed, and the calculated surfacing nitrogen tensions were depicted graphically for six tissues in each animal. It was found that small animals can surface with extremely high nitrogen tensions, particularly in the slower tissues, without serious ill effect. This appeared to be true even in the presence of bubble formation. A clinical description is given of a cat, surfaced from a saturation exposure at 350 ft (106.5 m) with 47 min decompression. It appears that the shorter circulation time of small animals did not by itself explain their immunity to bends.
Influence of reticuloendothelial hyperfunction on bone marrow transplantation
Authors: Wooles W. R. , Di Luzio N. R.
Published: December 2017

Reticuloendothelial (RE) hyperfunction was induced in C57/BL mice by the administration of trypsinized zymosan or glucan. The exposure of RE hyperfunctional mice to 800 r whole-body X-irradiation produced no change in phagocytic activity as denoted by the intravascular removal rate of colloidal carbon. The saline-injected control group showed a significant impairment in RE phagocytic activity. Reticuloendothelial hyperfunction existing at the time of bone marrow transplantation did not alter the high degree of recovery from radiation exposure afforded by isologous bone marrow transplantation. However, survival in RE hyperfunctional animals appeared to be correlated to the genetic diversity of the transplanted marrow since RE hyperactive animals receiving the homo- or heterografts manifested a 100% mortality as opposed to a 30-day survival of 90% and 25% in the respective saline-treated irradiated mice. These findings demonstrate that the early acceptance or rejection of the transplant is influenced by the functional state of the RES and the genetic variation of the transplant.
Electrical and mechanical activity of frog's heart in electrolyte-free solutions
Authors: Singh Inderjit
Published: December 2017

Frog's heart continues to beat in half isotonic solution of sucrose, 0.112 m, for 2–3 hr. The mechanical activity in sucrose is accompanied by electrical activity. After the heart has adjusted to sucrose, sodium chloride produces a temporary inhibition before rhythmic beats are restored. The effect of epinephrine and norepinephrine is reversed; they produce inhibition instead of stimulation after the heart has become adapted to the sucrose solution. Acetylcholine produces inhibition. As an explanation of excitatory phenomena in electrolyte-free solutions, it is suggested that responses are due to activation of intracellular excitation and conduction mechanisms, and that the external ions only condition the membrane.
Vagal inhibition of cardiovascular activity in the decerebrate cat
Authors: Glasser Richard L.
Published: December 2017

Cardiovascular responses after decerebration at three levels of the central neuraxis and subsequent vagotomy were studied in the cat. Midpontile decerebration produced a marked, transient depression in heart rate and arterial blood pressure, from which recovery to and sometimes above pretransection levels usually occurred within 30 min. Subsequent vagotomy in the midpontile decerebrate animals produced marked tachycardia and hypertension. This cardiovascular hyperactivity, particularly hypertension, was conspicuously diminished by stimulation of the central ends of the sectioned vagi. In distinct contrast to the dramatic augmentation of cardiovascular activity after vagotomy in the midpontile animals, vagotomy in midmesencephalic and medullary animals typically produced moderate and transient elevations in heart rate and blood pressure. These data support the concept of a cardiovascular-augmenter area in the caudal pons and a cardiovascular-depressor area in a more rostral portion of the brain stem. These data suggest that the vagal system antagonizes and masks a potential cardiovascular hyperactivity in the midpontile decerebrate animal.
Effect of neurogenic reflexes on heart rate during systemic hypotension
Authors: Ebert Paul A. , Austen W. Gerald , Greenfield Lazar J.
Published: December 2017

The effect of acute systemic hypotension on the heart was studied in the dog by maintaining coronary artery pressure at a constant level, using a separate perfusion system while the other tissues were perfused by a second separate extracorporeal circuit. In 14 dogs the systemic arterial pressure was acutely lowered to 25 mm Hg by a reduction in arterial flow. Dogs with total cardiac denervation showed no change in heart rate, myocardial contractile force, left atrial, or pulmonary arterial pressures during a 12-min period of hypotension. Normal dogs demonstrated an initial increase in heart rate of 9%; this was followed in 5–6 min by a 31% decrease in heart rate. Heart rate returned to control levels when systemic pressure was elevated or if the vagus nerves were divided. Dogs treated with reserpine showed only the decrease in heart rate and no initial cardiac acceleration. This study shows that the slowing of the heart observed during acute hemorrhage results, at least in part, from increased vagal activity.
Effect of hormones on pancreatic transplants in both normal and diabetic hamsters
Authors: Pansky B. , House E. L. , Jacobs M. S.
Published: December 2017

Five groups of mature male hamsters were used, each group containing normal and diabetic animals. Each animal received a transplant of neonatal pancreas. One group received no treatment. The other groups received: cortisone before transplantation; cortisone at the time of transplantation; cortisone and insulin; cortisone and growth hormone. It was found that cortisone in normal animals enhances development between the 10th and 24th days, with best results when given before transplantation. Among diabetics, cortisone improved growth but to a lesser degree, best results being obtained when started at the time of transplantation. A combination of cortisone and insulin gave normal animals a significant improvement beginning on the 10th day and continuing for the duration; among diabetics, improvement occurred but to a lesser extent. Although growth hormone significantly enhanced development in normal animals, beginning on the 13th day, the results were no better than after cortisone alone and were significantly inferior to those found after cortisone-insulin treatment. In the diabetic, growth hormone impeded development of the implant.
Calcium metabolism in relation to vitamin D and adrenal function in the chick
Authors: Sallis J. D. , Holdsworth E. S.
Published: December 2017

The influence of certain adrenal and synthetic steroids on calcium absorption has been tested in rachitic or vitamin D3-treated rachitic chicks. Long-term (3-day) administration of cortisol or deoxycorticosterone (DOC) interfered with the enhancement of Ca transport generally brought about by vitamin D3. The steroids had no effect on absorption by rachitic chicks. The effect was not a direct antagonism of the vitamin D3 effect, since cortisol, Δ' cortisol, or DOC enhanced the vitamin D3 effect when the steroids were injected intracardially 1 hr before the test. The effects can be correlated with interference of adrenal function when cortisol or DOC are administered for long periods. The theory is proposed that vitamin D3 is transformed into its active form in the adrenal cortex. Use of the specific inhibitor, 1-(2-chlorophenyl)-1-(4-chlorophenyl)-2, 2-dichloroethane, to interfere with adrenal function showed that this substance, when given for 3 days prior to the test, would eliminate the enhancement of Ca transport usually brought about by vitamin D3.
Effects of 3,5,3' -D-triiodothyronine on lipid metabolism in hypothyroidism
Authors: Merrill Joseph M. , Lemley-Stone Janet
Published: December 2017

To study the effects of 3,5,3'-d-triiodothyronine (d-T3) on oxygen consumption and lipid metabolism, thyroid deficiency was produced by administration of I131 to weanling rats. Hypothyroidism was evidenced by decreased growth and O2 consumption, with absence of functioning thyroid tissue at necropsy. Administration of d-T3 produced a transient fall in serum cholesterol and a more protracted fall in serum fatty acids. This was associated with a decrease in liver fatty acids and an increase in liver cholesterol. Simultaneously, incorporation of radioactive carbon into liver fatty acids and cholesterol of d-T3-treated animals was greatly increased. Total-body O2 consumption and Qo2 of myocardial homogenates were increased in animals treated with d-T3. From these data it is suggested that the hypolipemic and calorigenic effects of d-T3 are interdependent and administration at this dose level increases fatty acid utilization and cholesterol synthesis by the liver.
Nutritional status and physiological development of the preweanling rat
Authors: Heggeness F. W.
Published: December 2017

Heart rate and responses to cold stress and anoxia were studied in rapidly and slowly gaining preweanling rats. Relative availability of milk was varied so that some animals increased birth weight four times and others ten times during initial 21 days of extrauterine life. Core temperatures during cold exposure decreased more slowly in large as compared to smaller animals 5–20 days of age. Temperature regulatory capacity was nearly complete in 20-day-old animals weighing 40 g, but incomplete in equal aged animals weighing 20 g. Heart rate of the infant rat increased from 300 to 500 by 20 days. An initial increase to 400/min occurred by day 5 in both rapidly and slowly gaining rats. At day 10 and day 15 heart rates of heavier weight animals were significantly greater than those of lighter animals of the same age. Rapidly gaining animals achieved heart rates of 500/min by day 15; slowly gaining animals required 20 days. Tolerance to anoxia was not influenced by rate of weight gain up to 21 days of age.
Effect of acid in pyloric pouch on response of fundic pouch to injected gastrin
Authors: Gillespie Iain E. , Grossman Morton I.
Published: December 2017

In dogs, the acid response of a denervated fundic pouch to irrigation of an isolated pouch of the pyloric gland area with 0.5% acetylcholine was reduced by 87% when the pH of the irrigating solution was lowered from 7 to 1.3. In the same dogs, gastrin extract was given by continuous intravenous injection, the isolated pyloric pouch being irrigated alternately with 0.1 n NaHCO3 and 0.1 n HCI. No significant difference in acid response of the denervated fundic pouch was observed during acidification as compared to alkalinization. These findings support the hypothesis that acidification of the pyloric gland area prevents release of gastrin and provide further evidence against the view that acidification causes the release of an inhibitory humoral agent.
Potassium activation and K spikes in muscle fibers of the mealworm larva (Tenebrio molitor)
Authors: Belton Peter , Grundfest Harry
Published: December 2017

Muscle fibers of larval mealworms ( Tenebrio molitor) can be set to a wide range of resting potentials (ca. –40 to –90 mv), while remaining responsive to electrical stimuli. The initial resting potential is maintained long after K+0 is increased to levels well above the normal value (ca. 40 mEq/liter). However, spikes or graded responses are markedly affected by the level of K+0. For levels between 40 and 150 mEq/liter the terminal portion of the responses may become prolonged depolarizations, and for K+0 above about 200 mEq/liter positive overshoots occur. These changes follow the Nernst relation for K+0 > 20 mEq/liter. Thus, the membrane of the muscle fiber at rest is not a K electrode, but changes to the latter state during a response, indicating occurrence of K activation. The "K spikes" which develop in high K+0 lack an early depolarizing component, which is comparable to that subsumed under the Na activation and inactivation processes of the Hodgkin-Huxley theory. The K spikes may last for many seconds and are associated with increased membrane conductance throughout this time. The K spikes are probably terminated by a process of depolarizing K inactivation.
A central nervous system component of epinephrine hyperglycemia
Authors: Rosenberg Franklin J. , DiStefano Victor
Published: December 2017

At least half the hyperglycemic response (in hepatic venous blood) to intravenous epinephrine was found to be dependent on the integrity of the medulla oblongata caudal to the cerebellar peduncles. Transection of the medulla at the level of the fovea inferior unmasked a vagus-mediated hypoglycemic response to epinephrine. Changes in blood glucose concentration after epinephrine administration were independent of blood pressure and the base-line blood glucose levels. Microinjections of epinephrine into the floor of the fourth ventricle initiated an immediate hyperglycemic response without affecting blood pressure. It is concluded that only half the hyperglycemic response to epinephrine is due to direct peripheral action of epinephrine. The balance of the response is initiated by epinephrine-sensitive receptors in a hyperglycemic center in the floor of the fourth ventricle.
Respiration and phosphorylation of liver mitochondria from cold-exposed rats and chipmunks
Authors: Frehn John L. , Anthony Adam
Published: December 2017

Comparisons were made of the effects of cold exposure on respiration and phosphorylation of liver mitochondria in rats and chipmunks. Measurements, made polarographically, indicate that the P:O ratio was unaltered in mitochondria isolated from cold-exposed rats, cold-exposed nonhibernating chipmunks and hibernating chipmunks. No differences were found in the ratio of the respiratory rate in the presence of excess substrate and adenosine diphosphate (ADP) to the respiratory rate in the presence of excess substrate only (Rs) in cold-exposed rats or in chipmunks that failed to hibernate. However, the Rs value of hibernating chipmunks was higher than that of controls. This was due to an increased substrate-ADP respiratory rate. The substrate rate (i.e., without ADP) remained unchanged. It is suggested that the increased response to ADP of mitochondria from hibernating chipmunks may be an adaptive mechanism to aid the animal in the arousal process.
Effects of some pharmacologic agents on cold tolerance of dogs
Authors: Blatteis Clark M.
Published: December 2017

Eight unanesthetized, shaved dogs were studied in 32 experiments for their thermal and metabolic responses to 90 min of exposure to 6 C during peripheral vasoconstriction (metaraminol bitartrate, 0.3 mg/kg), peripheral vasodilatation (trimethaphan camphorsulfonate, 10 mg/kg), and increased heat production [2, 3-dinitrophenol (DNP), 2.5 mg/kg]. Skin and rectal temperatures were measured continuously by means of thermistors and recorded on a Heiland Visicorder. Oxygen consumption was determined by the open method at 15-min intervals. Shivering was monitored visually. In the cold, the temperatures of the metaraminol-vasoconstricted dogs fell more rapidly and lower than temperatures of controls, whereas the temperatures of the trimethaphan-vasodilated dogs decreased more slowly but also fell lower than those of controls; DNP retarded the temperature fall of these hypermetabolic dogs in the cold, but did not affect its degree. The vasodilating drug delayed the onset of shivering, whereas DNP hastened it; shivering in the vasoconstricted dogs began at a time not significantly different from that of controls.
Effect of ouabain on potassium exchange in hypothermic mammalian heart
Authors: Schreiber Sidney S. , Oratz Murray , Rothschild Marcus A.
Published: December 2017

Potassium exchange was studied in the intact working hypothermic guinea pig heart in vitro with K42. As at 37 C, buildup and washout experiments demonstrated two compartments of K exchange, but these behaved differently with reductions in temperature to 20 C. The rate of K exchange of the "fast" compartment decreased with lowered temperatures, whereas the rate of "slow" compartment exchange either remained unaffected or increased slightly. Ouabain had no apparent effect on the fast compartment K exchange. Toxic levels of ouabain, which inhibited entrance of K into the slowly exchanging phase at 37 C, showed a minimal effect on this compartment at 20 C. The decreased ouabain inhibition at 20 C was paralleled by a concomitant decrease in toxicity (contracture and ventricular fibrillation). It was postulated that intracellular cardiac K exchange involved two separate processes which responded differently to low temperatures. Ouabain action was indicated to be specifically on that process which was insensitive to cold temperatures.
Impulses in smooth muscle of rabbit deferent duct
Authors: Melton Carlton E. , Saldivar Julian T.
Published: December 2017

Action potentials and contractions were recorded from excised rabbit deferent ducts. Tissues from normal animals showed slow electrical waves accompanying local contractions. Castration caused spontaneous activity to increase. Deferent ducts from three of eight castrated animals showed propagation of evoked potentials; such activity was inhibited by testosterone and intensified by estradiol. Estradiol rendered deferent ducts from normal rabbits as active as those from castrated ones. Evoked responses in preparations from estrogen-treated animals were propagated at a mean velocity of 3.14 cm/sec (sd 1.98). Velocity was randomly variable within as well as between preparations. Impulse width was less than 5.0 mm but greater than 1.6 mm. Since the depolarized area spanned many cells it is concluded that some form of intercellular continuity exists.
Functional organization of ciliary muscle in the cat
Authors: Ripps Harris , Siegel Irwin M. , Getz William B.
Published: December 2017

Ocular accommodation was elicited by electric stimulation of the ciliary ganglion in cats. The responses to frequency variation were recorded before and after cutting a branch of the postganglionic motor supply to the ciliary muscle. At all stimulus frequencies the responses obtained after section were shown to be a constant fraction of those obtained in the intact preparation. This suggests that a fixed number of muscle cells are affected when a portion of the efferent nerve fibers is cut. It was concluded that smooth ciliary muscle is organized as independent functional units, akin to the motor-unit arrangement of skeletal muscle; a given nerve fiber influences the response of a limited number of muscle cells.
Renal reabsorption of amino acids
Authors: Ruszkowski Marian , Arasimowicz Cizesław , Knapowski Jan , Steffen Jan , Weiss Krystyna
Published: December 2017

Using the method of stop flow analysis an attempt was made to localize the process of amino acid reabsorption in the nephron of the dog. Special attention was given to the group of basic amino acids and cystine believed to share a common tubular transport mechanism. The evidence obtained in this study points clearly to the proximal segment as the site of intensive reabsorption of all amino acids investigated. During the infusion of arginine, lysine or ornithine, an increased excretion of two remaining basic amino acids plus cystine was observed, as a rule. Successful attempts were made to infuse cystine intravenously. The results of these experiments did provide the missing link for the hypothesis derived by Dent and Rose ( Quart. J. Med. 20: 205, 1951) concerning the common transport mechanism of arginine, ornithine, lysine, and cystine in the renal tubules. The functional cystinuria, which can be induced by saturating the common reabsorptive pathway with each of the above-mentioned amino acids, is fully reversible.
Arterial pressure changes by drugs injected into isolated pulmonary circulation in dogs
Authors: Takasaki Koichiro
Published: December 2017

In open-chested, anesthetized dogs the pulmonary venous outflow of the left lung was diverted into an external bypass so that the flow rate could be measured and blood prevented from returning immediately to the general circulation. Pulmonary arterial pressure was recorded in the left pulmonary artery; systemic arterial pressure and heart rate were also recorded. Injection of nicotine, veratrine, or Veriloid into this limited lung circulation produced a systemic depressor response and bradycardia. Both effects were abolished by vagotomy. It is concluded that these systemic cardiovascular effects are mediated through vagal chemoreceptors. There is no reason to implicate a mechanical pulmonary depressor reflex since these drugs produce no change in the pulmonary arterial pressure.
Effects of insulin and alloxan diabetes on glucose metabolism in rabbit aortic tissue
Authors: Mulcahy P. D. , Winegrad Albert I.
Published: December 2017

Tubular sections of rabbit thoracic aorta, free of adventitia, were incubated in vitro with uniformly labeled glucose-C14 in Krebs bicarbonate buffer. Lactate production accounted for the major portion of glucose uptake, oxidation to CO2 and incorporation of glucose carbon into glycogen and total lipid, for progressively smaller fractions. Insulin in vitro had no effect on glucose uptake or lactate production by tissue from normal or alloxan diabetic rabbits. Glucose uptake, lactate production, and the incorporation of glucose carbon in CO2, glycogen, and total lipid were markedly decreased by alloxan diabetes, and were not increased in insulin in vivo until after 18 hr of therapy. Marginal but consistent increases in the incorporation of carbon 14 into total lipid occurred in tissue from normal and diabetic rabbits with insulin in vitro; similar increases in the incorporation of glucose carbon into glycogen were observed. The bulk of the cellular components of the intima and media of the rabbit aorta appear to be insensitive to a direct or immediate insulin effect, but their glucose utilization is impaired by the diabetic state.
Propylthiouracil and hepatic clearance of thyroid hormones
Authors: Lang Stanley , Premachandra B. N.
Published: December 2017

Biliary radioactivity derived from injected tracer amounts of either radioactive thyroxin or triiodothyronine was increased following injection of propylthiouracil (PTU). In one experiment PTU was administered 18 hr and again 1 hr before the measurement of biliary radioactivity. The tracer hormones were injected just prior to the first of four hourly periods of bile collection. Total radioactivity and trichloroacetic acid-soluble radioactivity were determined in hourly plasma samples. In another experiment, thyroxin was injected 18 hr prior to bile collection. Radioactivity in bile collected from each animal for 1 hr was measured and then PTU was infused at a rate of 5 mg/hr intravenously by constant infusion pump for the next 2 hr. While large alterations were occurring in radioactivity of bile, no discernible alterations were seen in either total plasma counts or counts in the trichloroacetic acid-soluble fraction of the plasma. These results, considered along with those of other investigators, were interpreted to mean that PTU probably has more than one extrathyroidal effect on the metabolism of thyroid hormones.
l-Thyroxine on acetate conversion to cholesterol by livers of hypophysectomized rats
Authors: Nejad N. S. , Chaikoff I. L.
Published: December 2017

The effects of daily injections of 3 and 6 µg of thyroxine to normal and hypophysectomized rats, for 14 days, on the incorporation of C14 of acetate-1-C14 into fatty acids and cholesterol by slices of their livers were studied. The hormone administrations had no effect on the percentages of the C14 recovered as fatty acids and cholesterol in the experiments with livers excised from normal rats. In those with livers from hypophysectomized rats, however, the hormone treatments increased the incorporation of the C14 into cholesterol to a level about tenfold greater than that observed in normal rats.
Gastric secretion, continuously recorded blood sugar, and plasma steroids after insulin
Authors: Davis Richard A. , Brooks Frank P.
Published: December 2017

Gastric secretory response to insulin hypoglycemia (1.5 U/kg) was studied in ten experiments in four beagle dogs fitted with gastric fistulas. Blood sugar reduction was recorded continuously by means of an autoanalyzer. Plasma steroid concentrations were measured at hourly intervals. In seven of ten experiments gastric acid output was maximum 30–60 min after insulin was given. The onset of gastric secretion occurred 30–35 min after insulin, and the nadir of the blood sugar occurred 37 ± 4 min after insulin. Biphasic responses were seen only in two experiments. There was a delay of 13 ± 2 min before hypoglycemia began. The mean value of the lowest blood sugar was 28 ± 2 mg/100 ml. Plasma hydrocortisone concentrations increased to maximum values at 2 hr and then fell to control levels within 6 hr. In most experiments gastric secretion decreased as blood sugar levels returned to fasting values. Late phases could not be correlated with hypoglycemia or elevated plasma steroid concentrations.
Effects of tocopherol depletion on muscle nucleic acid and creatine levels in the frog
Authors: Gortner Ross A. , Milano Ann F.
Published: December 2017

Groups of adult male frogs were force fed on diets either devoid of fat and tocopherols or containing "stripped" corn oil with or without added α-tocopherol for 120 days. At the end of this period histological examinations of the gastrocnemius muscles and testes revealed no signs of degeneration in any dietary group. Biochemical studies on the muscle gave no reflection of tocopherol deficiency in the levels or proportions of total ribonucleic acid and deoxyribonucleic acid but did show a marked lowering of total muscle creatine in frogs on the tocopherol-free diets. The deficient animals subjected to considerable amounts of the polyunsaturated corn oil exhibited the lowest creatine levels. It is concluded that the adult frog has a dietary requirement for vitamin E and that more prolonged deprivation probably would result in the dystrophic symptoms commonly noted in other species.