Growth hormone requirement for a normal human adipocyte glucose carrier function

Area of Science:

• Endocrinology
• Metabolism
• Cell Biology

Background:

• Insulin stimulates glucose transport in adipose cells, but the precise mechanism remains unclear.
• Previous studies indicated a role for growth hormone (GH) in regulating insulin-sensitive glucose carriers in rat fat cells.

Purpose of the Study:

• To investigate the role of GH in human adipocyte glucose transport.
• To determine the effect of GH administration on glucose transport in GH-deficient (GHD) patients.

Main Methods:

• Isolated fat cells from normal individuals, GHD patients, and GH-treated GHD patients.
• Measured basal and insulin-stimulated glucose transport rates in adipocytes.
• Utilized collagenase digestion for fat cell isolation from subcutaneous biopsies.

Main Results:

• GHD patients' fat cells exhibited maximal basal glucose transport, unresponsive to insulin.
• GH treatment restored basal glucose transport to slow rates and insulin responsiveness.
• Confirmed GH's role in regulating a plasma membrane factor limiting basal glucose transport in human fat cells.

Conclusions:

• GH is crucial for normal insulin signaling and glucose transport in human adipose tissue.
• GH administration may benefit adult GHD patients by improving insulin sensitivity.
• GH acts by modulating a glucose transport-limiting factor in the adipocyte plasma membrane.