ABSTRACT
Roy G. Smith Merck Research Laboratories, Merck and Co., Inc., Rahway, New Jersey
I. INTRODUCTION: ELECTROPHYSIOLOGICAL STUDIES OF NEUROSECRETORY NEURONS
The secretion of growth hormone (GH) in the rat is sexually dimorphic. In both sexes secretion is pulsatile, but in males the pulses are larger, less frequent, and arise from a lower interpulse baseline than in females (1 ,2). The sexually dimorphic patterns of growth hormone secretion in the rat appear to derive from sexually dimorphic behavior of the somatostatin neurons, possibly reflecting the sexually dimorphic expression of androgen receptors by these neurons (3). In the male rat, GH-releasing factor (hormone) (GRF) and somatostatin are probably released alternately to produce peaks and troughs of growth hormone release (1,2,4), respectively, whereas in the female somatostatin is released more continuous! y.
