PMID- 9208304
OWN - NLM
STAT- MEDLINE
DCOM- 19970813
LR  - 20181130
IS  - 0016-6480 (Print)
IS  - 0016-6480 (Linking)
VI  - 107
IP  - 1
DP  - 1997 Jul
TI  - The effects of N-methyl-D,L-aspartate and gonadotropin-releasing hormone on in 
      vitro growth hormone release in steroid-primed immature rainbow trout, 
      Oncorhynchus mykiss.
PG  - 32-43
AB  - In the present study we investigated the effects of 17 beta-estradiol (E2) and 5 
      alpha-dihydrotestosterone (5 alpha DHT) on the ability of the glutamate agonist, 
      N-methyl-D,L-aspartate (NMA), to stimulate growth hormone (GH) release from 
      perifused pituitary glands of sexually immature rainbow trout (Oncorhynchus 
      mykiss). Two weeks after steroid hormone implantation, pituitary glands were 
      removed from the fish and challenged with NMA (10(-8) M) in a perifusion unit. 
      NMA rapidly and significantly elevated GH release from perifused pituitary 
      fragments taken from all treatment groups, and there was a main effect of in vivo 
      steroid hormone treatment on the in vitro GH response to NMA. To examine the 
      relationship between NMA and gonadotropin-releasing hormone on GH release, 
      pituitaries from E2- and 5 alpha DHT-primed and control fish were exposed to a 
      single pulse of salmon gonadotropin-releasing hormone (sGnRH) which also elicited 
      a significant elevation in GH release from perifused pituitary fragments, 
      although the response in the E2- and 5 alpha DHT-primed fish was significantly 
      smaller (P < 0.05) than that for the NMA challenge. Administration of a specific 
      GnRH antagonist, D-pGlu1,D-Phe2,D-Trp3,6-LHRH, did not affect the GH response to 
      NMA, whereas administration of the NMDA receptor antagonist 
      DL-2-amino-5-phosphonovaleric acid blocked the GH response to NMA. These data 
      suggest that NMA acts to stimulate GH release directly at the level of the 
      somatotroph, likely through the NMDA receptor and not through increased release 
      of GnRH.
FAU - Holloway, A C
AU  - Holloway AC
AD  - Department of Zoology, University of Guelph, Ontario, Canada.
FAU - Leatherland, J F
AU  - Leatherland JF
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - United States
TA  - Gen Comp Endocrinol
JT  - General and comparative endocrinology
JID - 0370735
RN  - 0 (Drug Implants)
RN  - 0 (Excitatory Amino Acid Agonists)
RN  - 08J2K08A3Y (Dihydrotestosterone)
RN  - 33515-09-2 (Gonadotropin-Releasing Hormone)
RN  - 4TI98Z838E (Estradiol)
RN  - 6384-92-5 (N-Methylaspartate)
RN  - 9002-72-6 (Growth Hormone)
SB  - IM
MH  - Animals
MH  - Dihydrotestosterone/pharmacology
MH  - Drug Implants
MH  - Estradiol/pharmacology
MH  - Excitatory Amino Acid Agonists/*pharmacology
MH  - Gonadotropin-Releasing Hormone/*pharmacology
MH  - Growth Hormone/drug effects/*metabolism
MH  - N-Methylaspartate/*pharmacology
MH  - *Oncorhynchus mykiss
MH  - Perfusion
MH  - Pituitary Gland/drug effects/*metabolism/ultrastructure
EDAT- 1997/07/01 00:00
MHDA- 1997/07/01 00:01
CRDT- 1997/07/01 00:00
PHST- 1997/07/01 00:00 [pubmed]
PHST- 1997/07/01 00:01 [medline]
PHST- 1997/07/01 00:00 [entrez]
AID - S0016-6480(97)96907-0 [pii]
AID - 10.1006/gcen.1997.6907 [doi]
PST - ppublish
SO  - Gen Comp Endocrinol. 1997 Jul;107(1):32-43. doi: 10.1006/gcen.1997.6907.