Episodic Growth Hormone Secretion in the Grass Carp, Ctenopharyngodon idellus (C. & V.)

Abstract The secretory pattern of growth hormone (GH) was studied in sexually immature grass carp (0.5-1.0 kg body wt). Serial blood samples were taken at l5-min intervals during 4- to 6-hr sampling periods via a dorsal aorta cannula. During each 4- to 6-hr sampling period plasma GH profiles demonstrated episodic secretion. Two patterns were observed, consisting either of one episodic of GH secretion (single or several pulses clustered) or two episodes of GH secretion during each sampling period. The interval between the two episodes of GH secretion was 2.6 hr. This is the first demonstration of episodic GH secretion in a teleost.