Effects of GRF with or without a SRIF antiserum on GH, IGF-1, thyroxin, cholecystokinin, gastrin and metabolite concentrations in growing rats.
This study was undertaken to examine the effects of increasing doses of rat somatocrinin (GRF) with or without a somatostatin antiserum (SS-ab) on serum hormone and metabolic concentrations, as well as serum and duodenal cholecystokinin (CCK) and antral gastrin concentrations. 24-day-old male Sprague-Dawley rats were injected twice daily s.c. (10:00 and 16:30) for 14 consecutive days with either saline or rat GRF (1-43) NH2 (4 and 20 micrograms/kg) in gelatin. Three other groups of animals received the same treatment in association with the SS-ab given i.p. every other day making up the 6 groups of 12 animals in a 2 x 3 factorial design experiment. GRF treatment increased circulating growth hormone (GH) concentrations in a dose-dependent manner, alone or in combination with the SS-ab; the SS-ab treatment alone or combined with GRF also increased GH concentrations. Total hypophyseal GH content was increased (P < 0.05) by the GRF treatment alone. Serum levels of IGF-1, acetoacetate, alpha 2 globulin and antral gastrin were all increased by the GRF treatment with plateaus observed for antral gastrin and serum IGF-1 levels at the intermediary dose of GRF. Serum concentrations of T4 were reduced at the 4 micrograms/kg dose of GRF. Serum concentrations of CCK were increased by the SS-ab treatment alone, an effect reversed by increasing doses of GRF. Rat GRF produced a dose-dependent increase and decrease of alpha 2 globulin and albumin, respectively. These data indicate that GRF, probably via its effect on GH release, influences gastrointestinal hormone levels which are implicated in gastrointestinal organ growth and digestive processes.
Département de Biologie, Université de Sherbrooke, Québec, Canada.
P
P
Dubreuil
P
P
Brazeau
J
J
Morisset
D000375:Aging / Q000378:metabolism*; D000818:Animals; D002766:Cholecystokinin / Q000097:blood*; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D005755:Gastrins / Q000097:blood*; D005914:Globins / Q000032:analysis; D013006:Growth Hormone / Q000097:blood*; D013007:Growth Hormone-Releasing Hormone / Q000494:pharmacology*; D007106:Immune Sera / Q000276:immunology / Q000494:pharmacology*; D007334:Insulin-Like Growth Factor I / Q000032:analysis*; D008297:Male; D011863:Radioimmunoassay; D051381:Rats; D017207:Rats, Sprague-Dawley / Q000254:growth & development*; D013004:Somatostatin / Q000276:immunology*; D013974:Thyroxine / Q000097:blood*
D005755:Gastrins; D007106:Immune Sera; D013004:Somatostatin; D007334:Insulin-Like Growth Factor I; D013006:Growth Hormone; D005914:Globins; D002766:Cholecystokinin; D013007:Growth Hormone-Releasing Hormone; D013974:Thyroxine