Physiologic response to hypoglycemia in normal subjects and patients with diabetes mellitus’

The early-morning increase in insulin requirements of patients with insulin-dependent diabetes mellitus (IDDM) has been referred to as the “dawn phenomenon.” To determine the roles of growth hormone levels and sympathoadrenal activity in this phenomenon, we studied six subjects with IDDM on four occasions during a constant overnight infusion of insulin. In control experiments (infusion of insulin alone), plasma glucose increased from 98 +/- 5 mg per deciliter at midnight to 225 +/- 36 at 8:00 a.m. (P less than 0.001), glucose production increased by 65 per cent (P less than 0.001), and glucose clearance decreased by 50 per cent (P less than 0.001). When nocturnal surges in growth hormone secretion were prevented by infusion of somatostatin plus replacement glucagon, neither plasma glucose levels nor glucose production increased significantly, and glucose clearance did not decrease. When nocturnal surges in growth hormone secretion were simulated by hourly intravenous injections of growth hormone (15 to 100 micrograms) during infusion of somatostatin and glucagon, plasma glucose levels and glucose production increased and glucose clearance decreased to values observed in control experiments. During combined alpha- and beta-adrenergic blockade (phentolamine and propranolol), values for plasma glucose, glucose production, and glucose utilization were not significantly different from those in control experiments. Increases in plasma glucose were significantly correlated with peak plasma growth hormone concentrations (r = 0.58, P less than 0.01). We conclude that nocturnal surges in growth hormone secretion are primarily responsible for the dawn phenomenon in patients with IDDM.

http://www.uptodate.com/patients/content/abstract.do;jsessionid=2C7CFEC6AA5FE638EBCCF0D3E895F6FC.1103?topicKey=~QS6mjpWrWG1eT4&refNum=24

 

Advertisements

One thought on “Physiologic response to hypoglycemia in normal subjects and patients with diabetes mellitus’

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s