Linked Life Data

3828428

Source:http://linkedlifedata.com/resource/pubmed/id/3828428

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
5
pubmed:dateCreated
1987-5-12
pubmed:abstractText
In multiparous rats, the incidence of regular estrous cyclicity and fertility decreases markedly at middle age. However, recent studies have shown that repeated pregnancies or progesterone (P) implants can subsequently cause retired breeder females to maintain regular cyclicity for an extended period of time; these results suggest a P-mediated deceleration of reproductive aging. In the present study, we examined the relation of ovarian steroid levels in young virgin females to their subsequent estrous cyclicity and reproductive function during aging as compared to multiparous females. Beginning at 4 mo of age and continuing to 6 mo of age, regularly cyclic virgin rats received either consecutive P implants (n = 41) or no implants (controls, n = 45) for 3 wk, followed by implant removal for 1 wk. Additional females (n = 72) were mated and allowed to undergo repeated pregnancies at 4, 6 1/2, and 8 mo of age. Blood samples were obtained throughout the estrous cycle (virgin females), during pregnancy (multiparous rats), and on Day 11 of successive treatments with P implants (virgins with P implants) for P, estradiol (E2), and testosterone (T) measurements. Subsequently, regularly cyclic females from all three groups were mated with fertile males to undergo term pregnancies at 10 and 12 mo of age. While the virgin controls showed cyclic increases in P, T, and E2 secretion during their estrous cycles, the P-implanted females had persistently low E2 and high P and T levels during treatment, which indicates an inhibition of ovarian E2 synthesis by P.(ABSTRACT TRUNCATED AT 250 WORDS)
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
0006-3363
pubmed:author
pubmed:issnType
Print
pubmed:volume
35
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1131-9
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1986
pubmed:articleTitle
The relation of ovarian steroid levels in young female rats to subsequent estrous cyclicity and reproductive function during aging.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.