Prolactin

During an oral glucose tolerance test (OGTT) glucose and insulin
levels were measured in 26 patients with prolactin-producing
pituitary tumours without growth hormone excess. Basal glucose and
insulin levels did not differ from the values of an age-matched
control group. After glucose load the hyperprolactinaemic patients
showed a decrease in glucose tolerance and a hyperinsulinaemia.
Bromocriptine (CB 154), which suppressed PRL, improved glucose
tolerance and decreased insulin towards normal in a second OGTT. —
Human PRL or CB 154 had no significant influence on insulin release
due to glucose in the perfused rat pancreas. — These findings
suggest a diabetogenic effect of PRL. CB 154 might be a useful drug
in improving glucose utilization in hormone-active pituitary
tumours.