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P Bartley

Publications and source records attributed to P Bartley.

3 recordsLinked to original sources
PubMed1978

Formation of DES-ASP1-angiotensin II is not an obligatory step in the steroidogenic action of angiotensin II in the canine adrenal.

A comparison of the receptor binding properties and in vitro metabolism of angiotensin II and [des-Asp1]-angiotensin II was performed in collagenase-dispersed glomerulosa cells from dog adrenal glands. Each peptide was bound rapidly and reversibly to isolated glomerulosa cells, with similar equilibrium and kinetic constants of association and dissociation. The labeled peptide that was bound to glomerulosa cells after incubation with 125I- and 3H-angiotensin II at 37C for 30-60 minutes was predominantly angiotensin II, with about 15% [des-Asp1]-angiotensin II. These findings demonstrate that local formation of the heptapeptide is not an obligatory step in the action of angiotensin II on aldosterone production in the canine adrenals.

Adrenal Glands↗
PubMed1978

An examination of possible mechanisms of angiotensin II-stimulated steroidogenesis.

Dog and rat adrenal glomerulosa cells and subcellular fractions have been utilized to evaluate the mechanism of angiotensin II- and angiotensin III-induced aldosterone production. The effects of angiotensin, ACTH, and potassium have been compared on cyclic AMP and cyclic GMP in isolated glomerulosa cells and adenylate cyclase activity in subcellular fractions. The effect of angiotensin II has also been assessed on Na+-K+-activated ATPase of plasma membrane enriched fractions of dog and rat adrenals. We have demonstrated no effect of angiotensin II or angiotensin III on either adenylate cyclase, cyclic AMP, cyclic GMP, or Na+-K+-dependent ATPase activity over a wide range of concentrations. Potassium ion in concentrations that stimulate significant aldosterone production was also without effect. The negative effects of angiotensin and potassium were contrasted against a positive correlation between an ACTH-induced effect on aldosterone production, adenylate cyclase, and cyclic AMP accumulation. These studies have served to demonstrate that neither adenylate cyclase, cyclic AMP, cyclic GMP, or Na+-K+-activated ATPase seem to be directly involved in the mechanism of action of angiotensins on aldosterone production in the rat and dog adrenal glomerulosa.

Adrenal Glands↗