Growth hormone and growth hormone-related mRNA in uremic rats: effect of a growth hormone secretagogue.
In experimental animals, the decreased growth during mild uremia is not accompanied by a loss in the capacity of the pituitary gland to secrete growth hormone (GH). With the development of orally administered GH "secretagogues" (GHS), it might be possible to stimulate growth during uremia without injections. This study was designed to determine the effects of the GHS, L-163,255. Uremia was induced by 5/6 nephrectomy (NX). GHS was given orally, 3 mg/kg, twice a week. Four groups of animals included: (1) sham-operated, (2) sham-operated, pair-fed, (3) uremic (NX), and (4) uremic, GHS-treated (NX+GHS). Blood sampling was conducted via intra-atrial catheters, and GH was quantitated. Pituitary GH mRNA was measured by Northern blot, and liver GH receptor and insulin-like growth factor-I mRNAs by RNAase protection. Untreated NX animals had a specific decrease in the "mass" of the GH pulses. A burst of GH was induced by GHS, but the pulsatile pattern of GH secretion over 6 h was not affected. An increase or a return to non-uremic levels of GH-related mRNAs occurred after GHS. Thus, GHS stimulated an acute burst of GH secretion and increased specific mRNAs encoding GH-related proteins in uremic animals.
Krieg
Richard J
RJ
Department of Anatomy, Medical College of Virginia Campus, Virginia Commonwealth University, P.O. Box 980709, Richmond, VA 23298-0709, USA. krieg@hsc.vcu.edu
Chan
Winnie
W
Lin
Kwei-Chi
KC
Kuemmerle
Nancy B
NB
Veldhuis
Johannes D
JD
Chan
James C M
JC
D000818:Animals; D015152:Blotting, Northern; D003404:Creatinine / Q000097:blood; D013006:Growth Hormone / Q000096:biosynthesis / Q000097:blood*; D006207:Half-Life; D007334:Insulin-Like Growth Factor I / Q000096:biosynthesis; D008099:Liver / Q000187:drug effects / Q000378:metabolism; D008297:Male; D009392:Nephrectomy; D010880:Piperidines / Q000494:pharmacology*; D010902:Pituitary Gland / Q000187:drug effects / Q000378:metabolism; D012333:RNA, Messenger / Q000096:biosynthesis*; D051381:Rats; D017207:Rats, Sprague-Dawley; D011986:Receptors, Somatotropin / Q000096:biosynthesis; D013141:Spiro Compounds / Q000494:pharmacology*; D014511:Uremia / Q000378:metabolism*
D010880:Piperidines; D012333:RNA, Messenger; D011986:Receptors, Somatotropin; D013141:Spiro Compounds; C102119:L 163255; D007334:Insulin-Like Growth Factor I; D013006:Growth Hormone; D003404:Creatinine