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Biomedical subjects

D B Goodman

Publications and source records attributed to D B Goodman.

124 records · Page 7Linked to original sources
PubMed1974

Effects of cytochalasin B on the response of toad urinary bladder to vasopressin.

A combined physiological and morphological study of the effects of cytochalasin B (CB) on the toad urinary bladder has been carried out. CB inhibits the hydro-osmotic response to vasopressin without altering basal water permeability or diffusion, or the increase in (3)H(2)O diffusion observed after hormone addition. Although CB increases [(22)Na]-, [(36)Cl]-, and [(14)C]urea fluxes, and decreases transepithelial potential, no alteration in basal short-circuit current, the vasopressin-induced increase in this parameter, or [(14)C]inulin permeability occurs. In the absence of hormone, CB does not markedly alter the structure of the toad bladder. However, in the presence of vasopressin, CB induces the formation of large intracellular vacuoles. These results suggest a possible coupling of solute and water movement across the tissue.

Animals↗
PubMed1972

Hormonal control of the renal conversion of 25-hydroxycholecalciferol to 1,25-dihydroxycholecalciferol.

Isolated renal tubules from vitamin D-deficient chicks catalyse the in vitro conversion of 25-hydroxycholecalciferol to 1,25-dihydroxycholecalciferol. This conversion is stimulated by 5 x 10(-10) M bovine parathyroid hormone, or by 10(-6) M cyclic AMP. It is inhibited by 10(-9) M porcine calcitonin. It is concluded that these hormonal controls of the synthesis of the renal hormone 1,25-dihydroxycholecalciferol are of particular physiological significance in coordinating the activities of the various organs involved in extracellular calcium homeostasis.

Animals↗
PubMed1970

Cyclic adenosine 3':5'-monophosphate-stimulated phosphorylation of isolated neurotubule subunits.

The possible relationship between cyclic adenosine 3':5'-monophosphate (cAMP) and neurotubules in synaptic transmission has been explored. The neurotubular subunit protein from bovine cerebral cortex has been prepared. The addition of cAMP to this preparation in the presence of ATP stimulates the phosphorylation of serine residue(s) in the principal component of the preparation. The neurotubule subunit thus serves as a substrate for an intrinsic, cyclic nucleotide-dependent protein kinase closely associated with the neurotubule subunit. The significance of this finding is discussed in terms of a general model for cellular secretion involving microtubules, cyclic AMP, protein kinase, and calcium ion.

Adenosine Triphosphate↗
PubMed1969

On the mechanism of action of aldosterone.

Studies to elucidate the mode of action of aldosterone have been carried out in the amphibian urinary bladder. The following previously reported hypotheses were evaluated: (1) aldosterone stimulates sodium transport by increasing the amount of sodium available to the sodium pump; (2) aldosterone enhances energy production for the sodium pump; and (3) aldosterone-stimulated sodium transport is obligatorily coupled to aerobic metabolism. In the present experiments, aldosterone potentiated the effect of vasopressin on sodium transport in the absence of aerobic metabolism or oxidative phosphorylation. This effect was not due to enhanced energy supply. Thus both hypotheses 2 and 3 appear not to be valid. In addition, aldosterone-stimulated sodium transport exhibited increased sensitivity to the specific inhibitor, ouabain, and this inhibition was readily reversed by K(+). These findings, as well as previously reported work, have led us to propose that aldosterone stimulates sodium transport by inducing a change either in the sodium pump itself, i.e., synthesis or activation, or in its environment in the serosal plasma membrane of the responsive cells.

Adenosine Triphosphatases↗