Paradoxical effects of oxytocin and vasopressin on basal prolactin secretion and the estrogen-induced prolactin surge

Journal Article · Sun Dec 31 23:00:00 EST 1989 · Life Sciences; (USA)

DOI:https://doi.org/10.1016/0024-3205(90)90217-F· OSTI ID:6039124

Mai, Leemin ^[1]; Pan, Jenntser ^[2]

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1. National Yang-Ming Medical College, Taipei (Taiwan)
2. Michigan State Univ., East Lansing (USA)

The roles of oxytocin (OT) and vasopressin (AVP) on both basal and estrogen-induced prolactin (PRL) secretion were examined. Adult female Sprague-Dawley rats that were ovariectomized for 3 weeks and received estrogen treatment for 1 week were used. Intravenous administration of hormones and serial blood sampling were accomplished through indwelling intraatrial catheters which were implanted two days before. Plasma PRL levels were measured by radioimmunoassay. Oxytocin at a dose of 20 {mu}g/rat stimulated a moderate PRL release in the morning and lower doses were without effect. Vasopressin was most effective at a dose of 5 {mu}g/rat in stimulating PRL release, while consecutive injections of higher doses were less effective. In contrast, TRH, ranging from 1 to 8 {mu}g/rat, induced a dose-dependent increases in PRL secretion. Using the effective dosages determined from the morning studies, repeated injections of either OT, AVP or their specific antagonists MPOMeOVT were given hourly between 1300 to 1800h and blood samples were obtained hourly from 1100 to 1900h. It was found that either OT or AVP significantly reduced the afternoon PRL surge, while their antagonists were not as effective.

• OSTI ID: 6039124
• Journal Information: Life Sciences; (USA), Journal Name: Life Sciences; (USA) Vol. 47:14; ISSN 0024-3205; ISSN LIFSA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ANIMALS
BIOASSAY
BIOCHEMICAL REACTION KINETICS
DIAGNOSTIC TECHNIQUES
DOSE-RESPONSE RELATIONSHIPS
ESTROGENS
GONADOTROPINS
HORMONES
IMMUNOASSAY
IMMUNOLOGY
ISOTOPE APPLICATIONS
KINETICS
LTH
MAMMALS
OXYTOCIN
PEPTIDE HORMONES
PITUITARY HORMONES
RADIOASSAY
RADIOIMMUNOASSAY
RADIOIMMUNODETECTION
RADIOIMMUNOLOGY
RATS
REACTION KINETICS
RODENTS
SECRETION
STEROID HORMONES
TRACER TECHNIQUES
VASOPRESSIN
VERTEBRATES