AJP - Endocrinology and Metabolism, Vol 270, Issue 6 E975-E979, Copyright © 1996 by American Physiological Society
Somatostatin infusion suppresses GH secretory burst frequency and mass in normal men
E. Calabresi, E. Ishikawa, L. Bartolini, G. Delitala, G. Fanciulli, O. Oliva, J. D. Veldhuis and M. Serio
Department of Clinical Physiopathology, University of Florence, Italy.
In attempting to elucidate the neuroendocrine mechanisms that regulate
pulsatile growth hormone (GH) secretion, we measured serum GH
concentrations by an ultrasensitive immunofluorometric method in blood
collected every 10 min for 8 h in 11 young healthy male volunteers (age
range 21-31 yr) before and during somatostatin (SS) administration (an iv
bolus dose of 350 micrograms followed by a continuous infusion at the rate
of 6 micrograms.kg-1.h-1, which increases the circulating SS levels to
approximately 570 pg/ml). Pulsatile GH secretion was analyzed using the
computer-assisted pulse detection program cluster method and deconvolution
analysis. The area and frequency of GH peaks were significantly reduced
during SS infusion compared with basal values, but detectable pulsatile
episodes were still present. These data suggest that, in adult males, SS
controls pulsatile GH secretion and can decrease the mass and frequency of
GH secretory bursts.
