Possible modulation of N-methyl-D,L-aspartic acid induced prolactin release by testicular steroids in the adult male rhesus monkey
- Quaid-i-Azam Univ., Islamabad (Pakistan)
N-methyl-D,L-aspartic acid (NMA), an agonist of the neurotransmitter glutamate has been shown to acutely stimulate the release of prolactin (PRL) in intact rats and monkeys. To further investigate the role of neuroexcitatory amino acids in PRL secretion, the effects of NMA administration were examined on PRL release in long term orchidectomized adult rhesus monkeys, in both the absence and presence of testosterone. Intact and long term castrated adult male monkeys weighing between 8-13 kg, were implanted with a catheter via the saphenous vein for blood withdrawal and drug infusion. Blood samples were collected at 10 min intervals for 50 min before and 70 min after administration of the drug or vehicle. Plasma PRL concentrations were estimated using radioimmunoassay. Whereas a single iv injection of NMA induced a prompt discharge of PRL in intact monkeys, an identical dose had surprisingly no effect on PRL secretion in orchidectomized animals. On the other hand, plasma PRL increases in response to a challenge dose of thyrotropin releasing hormone were similar in magnitude in the two groups of monkeys. Testosterone replacement in orchidectomized animals by parenteral administration of testosterone enanthate reinitiated the PRL responsiveness to acute NMA stimulation. These results indicate that N-methyl-D-aspartic acid (NMDA) dependent drive to PRL release in the adult male rhesus monkey may be overtly influenced by the sex steroid milieu.
- OSTI ID:
- 5699158
- Journal Information:
- Life Sciences; (United States), Vol. 49:15; ISSN 0024-3205
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ASPARTIC ACID
BIOCHEMICAL REACTION KINETICS
LTH
SECRETION
TESTOSTERONE
MONKEYS
RADIOIMMUNOASSAY
AMINO ACIDS
ANDROGENS
ANDROSTANES
ANIMALS
BIOASSAY
CARBOXYLIC ACIDS
DIAGNOSTIC TECHNIQUES
GONADOTROPINS
HORMONES
HYDROXY COMPOUNDS
IMMUNOASSAY
IMMUNOLOGY
ISOTOPE APPLICATIONS
KETONES
KINETICS
MAMMALS
ORGANIC ACIDS
ORGANIC COMPOUNDS
PEPTIDE HORMONES
PITUITARY HORMONES
PRIMATES
PROTEINS
RADIOASSAY
RADIOIMMUNODETECTION
RADIOIMMUNOLOGY
REACTION KINETICS
STEROID HORMONES
STEROIDS
TRACER TECHNIQUES
VERTEBRATES
550201* - Biochemistry- Tracer Techniques