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| Predicate | Object |
|---|---|
| rdf:type | |
| lifeskim:mentions | |
| pubmed:issue |
4
|
| pubmed:dateCreated |
1986-6-27
|
| pubmed:abstractText |
To assess the role of testosterone (T) in regulating the minute-to-minute release of pulsatile luteinizing hormone (LH) secretion in the adult male rat, we investigated the negative feedback of acute increases in plasma T concentrations on pulsatile LH secretion in acutely castrated male rats. At the time of castration, we implanted T-filled Silastic capsules, s.c., which maintained plasma T concentrations at approximately 1.8 ng/ml and suppressed LH pulses. On the next day, the capsules were removed; blood sampling (every 6 min) was started 8 h after implant removal, thereby allowing LH pulses to be reinitiated. Immediately following a control bleeding interval of 2 h, either T or vehicle alone was infused s.c., and blood sampling continued for another 4 h. In animals receiving vehicle alone, LH pulse frequency and mean LH levels increased over the 6 h bleeding period. The administration of 200 ng T/min caused a rapid rise in plasma T concentrations of about 4 ng/ml ("physiological") and prevented the increase in pulse frequency that occurred in the control group; it did not, however, reduce pulse frequency over the 4 h infusion period. When T was infused at the rate of 400 ng/ml, plasma T concentrations rose to approximately 18 ng/ml ("supraphysiological") and LH pulse frequency was significantly reduced, but not completely inhibited, during the last 2 h of the infusion. The pulse amplitude of luteinizing hormone did not change significantly in any of the groups.(ABSTRACT TRUNCATED AT 250 WORDS)
|
| pubmed:grant | |
| pubmed:language |
eng
|
| pubmed:journal | |
| pubmed:citationSubset |
IM
|
| pubmed:chemical | |
| pubmed:status |
MEDLINE
|
| pubmed:month |
May
|
| pubmed:issn |
0006-3363
|
| pubmed:author | |
| pubmed:issnType |
Print
|
| pubmed:volume |
34
|
| pubmed:owner |
NLM
|
| pubmed:authorsComplete |
Y
|
| pubmed:pagination |
624-9
|
| pubmed:dateRevised |
2007-11-14
|
| pubmed:meshHeading | |
| pubmed:year |
1986
|
| pubmed:articleTitle |
Effects of acutely increased plasma testosterone concentrations on pulsatile luteinizing hormone secretion in the male rat.
|
| pubmed:publicationType |
Journal Article,
Research Support, U.S. Gov't, P.H.S.
|