Selective nucleotide-release from dense-core granules in insulin-secreting cells.

• Secretory granules of insulin-secreting cells are used to store and release peptide hormones as well as low-molecular-weight compounds such as nucleotides. Here we have compared the rate of exocytosis with the time courses of nucleotide and peptide release by a combination of capacitance measurements, electrophysiological detection of ATP release and single-granule imaging. We demonstrate that the release of nucleotides and peptides is delayed by similar to 0.1 and similar to 2 seconds with respect to membrane fusion, respectively. We further show that in up to 70% of the cases exocytosis does not result in significant release of the peptide cargo, likely because of a mechanism that leads to premature closure of the fusion pore. Release of nucleotides and protons occurred regardless of whether peptides were secreted or not. These observations suggest that insulin-secreting cells are able to use the same secretory vesicles to release small molecules either alone or together with the peptide hormone.

Subject headings

MEDICIN OCH HÄLSOVETENSKAP  -- Medicinska och farmaceutiska grundvetenskaper (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Basic Medicine (hsv//eng)

MEDICIN OCH HÄLSOVETENSKAP  -- Klinisk medicin -- Endokrinologi och diabetes (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Clinical Medicine -- Endocrinology and Diabetes (hsv//eng)

Keyword

insulin

hormone

fusion pore

exocytosis

endocytosis

kiss-and-run

secretion

Exocytosis

Publication and Content Type

art (subject category)

ref (subject category)