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Biomedical subjects

Z Selinger

Publications and source records attributed to Z Selinger.

At least 109 records · Page 6Linked to original sources
PubMed1971

Potassium ion release and enzyme secretion: adrenergic regulation by alpha- and beta-receptors.

Epinephrine caused amylase secretion and K(+) release in rat parotid slices. Propranolol, which blocks beta-receptors, inhibited amylase secretion; phentolamine, which blocks alpha-receptors, inhibited K(+) release. Since enzyme secretion was associated with fusion of secretory granules to the cell membrane and K(+) release was associated with vacuole formation, it could be shown that both alpha- and beta-receptors are present in the same exocrine cell. The findings appear to exclude cyclic 3',5'-adenosine monophosphate as an intermediate in the alpha-receptor response.

Adrenergic alpha-Antagonists↗
PubMed1971

Epinephrine-induced vacuole formation in parotid gland cells and its independence of the secretory process.

Catecholamines cause rapid release of K(+) and formation of vacuoles in acinar gland cells. A high K(+) concentration in the medium bathing parotid gland slices prevents vacuole formation by epinephrine and facilitates the secretion of most of the exportable amylase. N(6)-monobutyryl 3':5'-cyclic AMP does not cause K(+) release and vacuole formation although it efficiently induces amylase secretion. It is suggested that the secretory process is independent of vacuole formation.

Amylases↗
PubMed1971

Concomitant synthesis of membrane protein and exportable protein of the secretory granule in rat parotid gland.

After enzyme secretion the membrane of the secretory granule, which had been fused to the cell membrane, was resorbed into the cell. Experiments were therefore carried out to test whether formation of new secretory granules involves reutilization of the resorbed membrane or synthesis of a new membrane, de novo, from amino acids. Incorporation of amino acids-(14)C into proteins of various cell fractions was measured in vivo, 30, 120, and. 300 min after labeling. At all times the specific radioactivity of the secretory granule membrane was about equal to that of the granule's exportable content. At 120 and 300 min the specific radioactivity of the granule membrane and of the granule content was much higher than that of any other subcellular fraction. It is therefore concluded that the protein of the membrane is synthesized de novo concomitantly with the exportable protein. The proteins of the granule membrane could be distinguished from those of the granule content by gel electrophoresis. All major bands were labeled proportionately to their staining intensity. The amino acid composition of the secretory granule membrane was markedly different from that of the granule's content and also from that of the mitochondrial membrane. The granule membrane showed a high proline content, 30 moles/100 moles amino acids. The analyses show that the radioactivity of the granule membrane is indeed inherent in its proteins and is not due to contamination by other fractions. The possibility is considered that the exportable protein leaves the endoplasmic reticulum already enveloped by the newly synthesized membrane.

Amino Acids↗