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R W Retallack

Publications and source records attributed to R W Retallack.

47 records · Page 3Linked to original sources
PubMed1972

The isolation of a renally active substance from arterial blood.

1. A substance (Art. HS) which resembles the 18-monoacetate of D-aldosterone (18 MA) in its biological actions is found in arterial blood of cats and sheep: Art. HS is assayed in terms of antidiuretic activity equivalent to synthetic 18 MA.2. In cats under chloralose anaesthesia, dialysis of arterial blood (2-3 ml./min) in a small external circuit (8-15 ml.) without disturbance of heart rate, blood pressure or respiration, predicts a physiological concentration of Art. HS equivalent to 31.5-51.9 ng 18 MA/100 ml. Efficiency of dialysis assumed in this calculation is 100%.3. Art. HS is almost evenly distributed throughout the plasma and formed elements of blood.4. Concentrations of Art. HS found during severe arterial haemorrhage are equivalent to 188 +/- 6.7 and 151 +/- 9.2 ng 18 MA/100 ml. in cats and sheep respectively.5. Art. HS has been isolated from 27.6 l. sheep arterial blood by ethyl acetate: chloroform 1:1 extraction, defatting by partitioning between methanol and petroleum ether and purifying by seven-stage thin layer chromatography on MN Kieselgel UV(254). Final yield was equivalent in activity to 21.6 mug 18 MA. Synthetic 18 MA was used as R(F) marker. Spots of 2 mug 18 MA are visible on MN Kieselgel UV under U.V. Art. HS activity equivalent to 21.6 mug 18 MA cannot be seen.6. Art. HS was not detectable in IVC blood of cats under chloralose anaesthesia during haemorrhage. The threshold for detection was the equivalent of 15-20 ng 18 MA/100 ml.7. Art. HS resembles a substance liberated by the heart (Lockett & Retallack, 1970a, b, 1971) in chromatographic properties, biological properties and stability in aqueous solution. Art. HS is very much more stable in aqueous solution than 18 MA.

Aldosterone↗
PubMed1972

The extent of the destruction, during passage through the lungs, of a substance secreted by the heart.

1. In vitro, the lungs of male Wistar rats, 220-230 g, removed heart substance (HS) from saline perfusates. HS could not be recovered by subsequent perfusion with HS free solution.2. A maximum rate of HS-uptake, 8.5 ng biological equivalents of 18-monoacetate of D-aldosterone (18 MA)/min, was reached at a concentration of HS equivalent to 3.5 ng 18 MA/ml. at a flow of 6 ml./min.3. Uptake was not significantly affected by a fall in temperature from 38 to 18-20 degrees C or by reduction in P(CO) (2) to zero. Uptake was reduced by anoxia and was enhanced by decrease of pH from 7.4 to 6.6.4. 30% of the HS taken up by the lungs at 20 degrees C was recoverable: none of the HS taken up at 38 degrees C was recovered.5. Uptake of HS by binding is considered rate-limiting to the destruction of HS in the lungs.6. The concentrations of HS found in the pulmonary and carotid arterial blood of cats under chloralose anaesthesia, during haemorrhage, were biologically equivalent to 1098 +/- 38.7 and 169 +/- 13.4 ng 18 MA/100 ml. (means +/- S.E.) respectively, in four experiments.

Acetates↗
PubMed1971

The release of a renally active substance by perfused rat hearts.

1. A substance (HS) which resembles the 18-monoacetate of D-aldosterone (18-MA) in its biological actions is released by perfused rat hearts, HS is assayed in terms of activity equivalent to synthetic 18-MA.2. Isolated rat hearts perfused with modified Krebs bicarbonate Ringer without recirculation secrete progressively less and less HS.3. Addition of D-aldosterone to recirculating perfusate supplying a heart no longer secreting measurable quantities of HS causes a rapid and very marked increase in the output of HS from the heart. If radioactively labelled D-aldosterone is supplied the HS synthesized is radioactively labelled. No measurable amounts of HS are formed from 18-hydroxycorticosterone.4. Chromatographic differentiation between 18-MA and HS, initially difficult, has been achieved.5. The rate of secretion of HS from the hearts of adrenalectomized animals is markedly reduced: synthesis of HS is immediately resumed when these hearts are supplied with D-aldosterone, but at a subnormal rate.

Acetates↗
PubMed1970

The influence of heart rate on the secretion of a substance closely resembling the 18-monoacetate of D-aldosterone by the hearts of cats under chloralose anaesthesia.

1. A substance (HS), similar to the 18-monoacetyl derivative of D-aldosterone (18 MA) in its physico-chemical and biological properties, is shown to be secreted into the coronary circulation by cat hearts, in vivo.2. The concentrations found in coronary sinus blood from cats resting under chloralose anaesthesia ranged from 20 to 36 ng/ml. equivalent 18 MA activity.3. A positive correlation was found between heart rate and the concentration of HS in coronary sinus blood. This concentration was doubled by a rise in heart rate of 65 +/- 20.2 beats/min when the tachycardia was induced by electrical drive from the right atrial appendage. An increase of only 22.5 +/- 1.76 beats/min doubled the concentration of HS when the acceleration was induced by infusion of adrenaline, noradrenaline or isoprenaline or by atropinization.4. Two methods are described for bio-assay of HS. The reference compound used was 18 MA.

Aldosterone↗
PubMed1970

Factors controlling the secretion of a substance biologically resembling the 18-monoacetate of D-aldosterone by heart muscle.

1. Previous work has demonstrated that the cat heart secretes a substance which resembles the 18-monoacetate of D-aldosterone (18 MA) in chromatographic properties and biological actions. This substance (HS) releases ADH from the neurohypophysis and, in higher concentration, causes renal retention of salt and water. HS is extracted from blood, separated chromatographically and assayed in terms of equivalent 18 MA activity either by inhibition of water diuresis in rats or by reduction of the excretion of Na by the isolated kidney. Positive correlation has been demonstrated between heart rate and HS secretion.2. Heart-lung preparations from cats have been used to disclose additional factors controlling the rate of secretion of HS from heart muscle.3. Positive inotropic effects produced by administration of digoxin or adrenaline or by increase in peripheral resistance are associated with increases in the secretion of HS.4. Negative inotropic effects produced by high concentrations of procaine hydrochloride or by increase in venous return without change in external work are associated with decrease in HS secretion.

Acetates↗
PubMed1969

The isolation of a substance very closely resembling the 18-monoacetate of D-aldosterone from the venous blood of activated muscle and from contracting muscle.

1. A renally active substance can be extracted in detectable quantity from 150 g flash-frozen active but not from 150 g flash-frozen flaccid striped muscle. This substance is identical to the 18-monoacetate of D-aldosterone (18-MA) in R(F) value in three solvent systems and in biological activity.2. The renally active substance is secreted into the blood stream by active but not by flaccid muscles.3. Bilateral stimulation of decentralized sciatic nerves causes diuresis, natriuresis, a rise in the clearances of creatinine and PAH without change in heart or respiratory rates, in cats under chloralose anaesthesia. These changes can be matched by I.V. infusion of ADH, 0.3-0.45 m-u./kg.min.4. The urinary changes caused by sciatic stimulation are not prevented by transection of the spinal cord but are abolished by hypophysectomy.5. Hence, like 18-MA, the muscle substance liberates ADH from the neurohypophysis.

Aldosterone↗
PubMedDate not supplied

Abnormal thyroid stimulating hormone following pituitary surgery.

Biologically inactive thyroid stimulating hormone (TSH) has been reported in hypothyroid patients. We report the first case of immunoreactive, but abnormal TSH in a euthyroid patient following hypophysectomy for a prolactin secreting pituitary adenoma. Indirect evidence indicates that this abnormal TSH was biologically inactive. The TSH was characterized by gel chromatography and has a molecular weight of approximately 23,000 daltons.

Adenoma↗