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Biomedical subjects

H G Gullner

Publications and source records attributed to H G Gullner.

13 recordsLinked to original sources

Diabetes insipidus with renal resistance to vasopressin in the desoxycorticosterone-treated dog: a possible role for prostaglandins.

We examined the release of vasopressin and the renal response to exogenous vasopressin before and during desoxycorticosterone acetate (DOCA) administration in the dog. As treatment with DOCA produced potassium loss, urine volume increased, urinary osmolality decreased, and urinary PGE2 tended to increase. The increase in urine volume was accompanied by increases in serum sodium, in plasma osmolality and in plasma arginine vasopressin. The threshold for vasopressin release measured during polyuria was higher than control but the rate of vasopressin release was unchanged. The DOCA-induced polyuria was not affected by treatment with vasopressin which further increased plasma vasopressin. Treatment with indomethacin which corrected the increase in urinary PGE2 excretion but not the hypokalemia, restored the renal responsiveness to vasopressin, decreased the secretion of vasopressin, and corrected the polyuria and the hypernatremia. These findings suggest that DOCA-induced polyuria is attributable to a decrease in renal responsiveness to vasopressin which may be mediated in part by an increase in the renal synthesis of prostaglandins.

Animals↗

Demonstration and distribution of kassinin-like material (substance K) in the rat central nervous system.

Antiserum was raised against kassinin in rabbits. Cross-reactivity with other tachykinins was determined; these included substance K (100%) and substance P (0.1%). Peptides extracted from rat brain and synthetic tachykinins were chromatographed by reverse-phase HPLC. The major peak of kassinin-like material eluted at a time different from that of synthetic kassinin, eledoisin, physalaemin, neurokinin beta, and substance P but coeluted with substance K. Measurement of kassinin-like material in macrodissected and microdissected brain regions indicated that the distribution of kassinin-like material was similar to that of substance P.

Animals↗

Essential hypertension: central and peripheral norepinephrine.

The concentration of norepinephrine in cerebrospinal fluid from patients with essential hypertension is higher than that from healthy normal volunteers, but the concentrations of norepinephrine in plasma from these groups are similar. This finding indicates that central nervous system noradrenergic hyperactivity occurs in essential hypertension but apparently is not reflected in abnormal function of the peripheral sympathetic nervous system in these patients.

Adult↗

Correction of increased prostacyclin synthesis in Bartter's syndrome by indomethacin treatment.

The role of prostacyclin and thromboxane A2 in the pathogenesis of Bartter's syndrome was investigated by measurement of the urinary excretion of 6-keto-PGF1 alpha and thromboxane B2, respectively, in five patients. The prostaglandin metabolites were extracted from urine by a reproducible method and measured by specific radioimmunoassays. The patients with Bartter's syndrome excreted about four-times as much 6-keto-PGF1 alpha as the normal controls. In contrast, there was no significant difference in the urinary excretion of thromboxane B2 between the patients and the controls. In a second part of the study, three patients were treated with indomethacin (150 mg/day for four days), an inhibitor of prostaglandin synthesis. This regimen suppressed urinary excretion of 6-keto-PGF1 alpha by 43% and that of thromboxane B2 by 46%. It is suggested that the increase in prostacyclin production is responsible for both the hyperreninemia and and the other endocrine derangements as well as the hyporesponsiveness of blood pressure to intravenous infusion of vasopressors in patients with Bartter's syndrome.

6-Ketoprostaglandin F1 alpha↗

The role of urinary prostaglandin E and cyclic AMP in the polyuria of hypokalemia in rats.

The effect of potassium depletion on urinary prostaglandin E and cyclic AMP excretion was studied in female Sprague-Dawley and in Brattleboro rats. The animals were fed a potassium-free diet for 20 days which resulted in an average decrease in serum potassium of 25% in both strains. In the Sprague-Dawley rats, potassium depletion increased urine volume from 5.5 +/- 0.9 ml/day to 25.9 +/- 3.5 ml/day (p less than 0.001), decreased urinary osmolality from 1483 +/- 87 mosmol/kg H2O to 372 +/- 12 mosmol/kg H2O (p less than 0.001) and suppressed urinary cyclic AMP excretion from 56.95 +/- 3.81 nmoles/day to 0.83 +/- 0.40 nmoles/day (p less than 0.001). Potassium depletion in the Brattleboro rats did not affect these parameters. Excretion of prostaglandin E-like immunoreactivity in urine did not change in either strain with potassium depletion. The findings support the hypothesis that prostaglandins do not play a significant role in the polyuria caused by potassium deficiency in rats. Hypokalemia may cause polyuria by suppression of vasopressin-sensitive cyclic AMP generation, leading to a decrease in water permeability.

Animals↗

Prostacyclin has effects on proximal and distal tubular function in the dog.

The effect of prostacyclin (PGI2), the major metabolite of arachidonic acid in arterial and venous tissue, on renal function was studied in hypophysectomized dogs under conditions of a maximum water diuresis. PGI2 (0.04 microgram/kg/min) significantly increased urine flow and urinary sodium and potassium excretion without affecting glomerular filtration rate. In addition, PGI2 significantly increased free water clearance and distal delivery of sodium and inhibited distal fractional reabsorption of glomerular filtrate. This suggests an effect of PGI2 on proximal as well as distal segments of the nephron. PGI2 is about 10 times more potent than PGE2 with regard to natriuresis and diuresis when studied under identical conditions. Thus, PGI2 may be the major prostaglandin involved in salt and water excretion.

Animals↗

Adrenergic receptor function is different in male and female patients with essential hypertension.

As plasma norepinephrine (NE) levels may be similar in hypertensive and normotensive subjects, the sensitivity of adrenergic receptors was investigated in patients with essential hypertension and normotensive subjects of similar age and sex. Alpha-adrenergic receptor sensitivity was measured in platelets by the specific binding of [3H]dihydroergocryptine and the NE inhibition of prostaglandin E1 (PGE1)-stimulated cyclic AMP (cAMP) production. The number of alpha-adrenergic receptors in platelets from hypertensive women was 1.5 times that in the platelets from normotensive ones, with no differences between hypertensive and normotensive women or between men and women in the affinity of the alpha-adrenergic receptor for [3H]dihydroergocryptine. PGE1-stimulated cAMP production was half as great in hypertensive as in normotensive men, while NE inhibition of PGE1-stimulated cAMP production was similar in hypertensive and normotensive men and women. [3H]Dihydroergoeryptine binding in female hypertensives, and PGE1-stimulated cAMP in male hypertensives did not differ from that in sex-matched controls. The sensitivity of the beta-adrenergic receptor, measured by [3H]dihydroalprenolol binding and cAMP production was similar in hypertensive and normotensive subjects.

Cyclic AMP↗