Feed intake and serum GH, LH and cortisol in gilts after intracerebroventricular or intravenous injection of urocortin

In three experiments (Exp), ovariectomized gilts received intracerebroventr icular (ICV; Exp 1 - with restraint, Exp 2 - without restraint) or intraven ous (i.v.; Exp 3) injections of urocortin or saline to assess effects on fe ed intake and serum GH, LH, and cortisol. Following a 20-hr fast, feed was presented at 1 hr (Exp 1) or 30 min (Exp 2 and 3) after injection (time = 0 hr) of saline or 5 (U5) or 50 (U50) mug/pig (Exp 1 and 2) or 5 mug/kg BW ( Exp 3) of urocortin. Blood samples were collected every 15 min from -2 to 6 hr relative to injection and hormone data pooled 2 hr before and hourly af ter treatment. Treatment with U50 decreased feed intake, relative to saline (treatment x time interaction; P < 0.05), when delivered ICV but not i.v. A treatment by time interaction was detected for GH (Exp 1, 2, 3) and LH (E xp 1 and 2; P < 0.01). Serum GH increased over time (relative to -2 hr; P < 0.05) following treatment with urocortin but not saline regardless of rout e of administration. Conversely, in Exp 1 (U5 and U50) and Exp 2 (U50), LH decreased relative to -2 hr with a delayed decrease during Exp 1. Serum cor tisol was not affected by treatment in Exp 1, but increased following uroco rtin in Exp 2 and 3 (treatment by time interaction, P < 0.01). These data p rovide evidence that urocortin modulates GH and LH concentrations and suppr esses feed intake in gilts via mechanisms which may be independent of corti sol and may depend upon dose and route of administration. (C) 2000 Elsevier Science Inc. All rights reserved.