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| Predicate | Object |
|---|---|
| rdf:type | |
| lifeskim:mentions | |
| pubmed:issue |
3
|
| pubmed:dateCreated |
1997-4-16
|
| pubmed:abstractText |
Prolactin (PRL) and other lactogenic hormones feed back at the hypothalamus to inhibit PRL release. At midpregnancy, high circulating levels of placental lactogens (PL) terminate the mating-induced biphasic PRL surges in female rats. In the dark period preceding parturition, however, an ante-partum PRL surge occurs despite continuously high levels of PL. This study examined whether the lactogenic hormone negative feedback loop is altered during the ante-partum surge using two models: (i) pregnant rats given a hypothalamic implant of albumin, ovine PRL, or recombinant rat PL-I on Day 19 or 20 of pregnancy; and (ii) pregnant rats bearing a transplant of a rat choriocarcinoma cell line, Rcho-1 (PL-secreting), or HRP-1 (non-PL-secreting). Serial blood samples were taken via carotid cannula from all rats. Although lactogenic hormones placed in the hypothalamus reduced suckling-induced PRL release by 89%, hypothalamic implants of oPRL or recombinant rPL-I did not attenuate the ante-partum PRL surge. Rcho-transplanted rats also did not have a significantly reduced ante-partum PRL surge (peak PRL level, 131 ng/ml) compared with HRP-bearing rats (peak PRL level, 107 ng/ml). Northern blot analysis revealed that the Rcho-1 tumors expressed both PL-I and PL-II, while the HRP-1 tumors did not express either PL. The inability of the Rcho-1 transplants to inhibit the ante-partum PRL surge suggests that lactogenic hormone negative feedback is disrupted during the ante-partum period, possibly by the changing steroid profile associated with parturition.
|
| pubmed:grant | |
| pubmed:language |
eng
|
| pubmed:journal | |
| pubmed:citationSubset |
IM
|
| pubmed:chemical |
http://linkedlifedata.com/resource/pubmed/chemical/Placental Lactogen,
http://linkedlifedata.com/resource/pubmed/chemical/Prolactin,
http://linkedlifedata.com/resource/pubmed/chemical/RNA, Messenger,
http://linkedlifedata.com/resource/pubmed/chemical/RNA, Neoplasm,
http://linkedlifedata.com/resource/pubmed/chemical/placental lactogen I, rat
|
| pubmed:status |
MEDLINE
|
| pubmed:month |
Mar
|
| pubmed:issn |
0037-9727
|
| pubmed:author | |
| pubmed:issnType |
Print
|
| pubmed:volume |
214
|
| pubmed:owner |
NLM
|
| pubmed:authorsComplete |
Y
|
| pubmed:pagination |
258-64
|
| pubmed:dateRevised |
2007-11-14
|
| pubmed:meshHeading |
pubmed-meshheading:9083259-Animals,
pubmed-meshheading:9083259-Animals, Suckling,
pubmed-meshheading:9083259-Body Weight,
pubmed-meshheading:9083259-Choriocarcinoma,
pubmed-meshheading:9083259-Feedback,
pubmed-meshheading:9083259-Female,
pubmed-meshheading:9083259-Hypothalamus,
pubmed-meshheading:9083259-Lactation,
pubmed-meshheading:9083259-Neoplasm Transplantation,
pubmed-meshheading:9083259-Placental Lactogen,
pubmed-meshheading:9083259-Pregnancy,
pubmed-meshheading:9083259-Prolactin,
pubmed-meshheading:9083259-RNA, Messenger,
pubmed-meshheading:9083259-RNA, Neoplasm,
pubmed-meshheading:9083259-Rats,
pubmed-meshheading:9083259-Rats, Sprague-Dawley,
pubmed-meshheading:9083259-Sheep,
pubmed-meshheading:9083259-Uterine Neoplasms
|
| pubmed:year |
1997
|
| pubmed:articleTitle |
Lactogenic hormones of the placenta and pituitary inhibit suckling-induced prolactin (PRL) release but not the ante-partum PRL surge.
|
| pubmed:affiliation |
Department of Physiology, Kansas University Medical Center, Kansas City 66160-7401, USA.
|
| pubmed:publicationType |
Journal Article,
Research Support, U.S. Gov't, P.H.S.,
Research Support, U.S. Gov't, Non-P.H.S.
|