60 Prolactin (Prl) Secretion in Long-term Survivors of Acute Lymphoblastic Leukemia (ALL)

Abstract

The therapy employed for the treatment of childhood ALL is known to cause disturbances in the neuroendocrine control of growth hormone (GH) secretion. Recent data suggest that this is due primarily to hypothalamic damage. Since Prl levels are frequently elevated and diurnal variation is lost when hypothalamic damage is present, we assessed Prl secretion in a group of long-term survivors of ALL. We studied 5 males between the ages of 11 8/12 - 20 5/12 yrs. The patients were euthyroid and had been off treatment for 2-10 yrs. 4 of 5 had received cranial radiation (2400 rads). 2 of 4 irradiated patients had demonstrated blunted peak GH levels (<7 ng/ml) during sleep. Prl levels were determined in PM prior to sleep (q 30 min) and q 20 minutes during sleep.The awake PM Prl concentrations in patients (8.7 ± 1.0 ng/nl) were not different from controls (5.6± 0.8 ng/ml). The patients' mean Prl levels during sleep (13.9 ± 0.7 ng/ml) and mean Prl output (476 ± 98 area units) were not significantly different from those of the controls (9.0 ± 0.4 ng/ml and 333 ± 40 area units). All patients showed normal augmentation of Prl during sleep. These results suggest that the neuroendocrine mechanisms controlling Prl secretion are less sensitive to the toxic effects of ALL therapy than those controlling GH secretion.