Linked Life Data

2791965

Source:http://linkedlifedata.com/resource/pubmed/id/2791965

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
1989-11-7
pubmed:abstractText
The secretory response of the primate corpus luteum (CL) to CG after implantation suggests that gonadotropin receptors are not depleted despite increasing CG production and continuous elevated tropic stimulation. Such continuous stimulation is known to cause down-regulation of receptors in other tissues. To determine if CG secretion is intermittent during the initial stages of CL rescue, we assessed the secretory pattern of CG during the periimplantation period by collecting frequent (4/h) blood samples in two studies (for 4 h on 3 separate days between days 8-13, or for 2 separate 13-h sequences between days 10-15 postovulation) in 13 chair-adapted females. Day 0 of gestation was defined as the day of ovulation, as estimated by peak urinary estrone conjugate excretion in females mated on days 9, 11, and 13 of the menstrual cycle. Hormone concentrations were measured by either RIA [irFSH; estradiol and progesterone (P)] or Leydig cell bioassay (bioLH or bioCG). In the first study, 4 of 6 females conceived, and the mean for bioLH was not significantly elevated until days 12-13. In the second study, 5 of 7 females conceived, and the episodic secretory pattern of circulating pituitary bioLH typically observed in cycling females (2.7 +/- 0.3 peaks/13 h) was replaced by a relatively nonpulsatile, but steadily increasing profile during days 12-15 of gestation (1.5 +/- 0.4 peaks/13 h). Although occasional large fluctuations in bioLH/CG and P were noted, the bioLH/P peaks were less congruent than those in nonfertile cycles, and there was no diurnal pattern in the secretion of either hormone. In contrast, irFSH concentrations did not fluctuate and were similar in the two groups of females [2.93 +/- 0.28 vs. 2.34 +/- 1.7 ng/ml (mean +/- SEM)]. These data demonstrate that 1) a steady, gradually increasing secretory pattern of CG is associated with rescue of the CL; 2) the circulating profile of CG during the periimplantation interval is not consistently episodic and does not support the hypothesis that intermittent CG release prevents LH/CG receptor down-regulation in the CL during early pregnancy; 3) increased bioLH/CG levels during conceptive cycles in rhesus monkeys are not detected until days 12-13 after the midcycle bioLH peak; 4) irFSH patterns on pooled aliquots appear to be uninformative with regard to gonadotropin dynamics in early pregnancy; and 5) urinary estrone conjugate measurements provide a practical method for the precise timing of infrequent events, such as implantation, in the laboratory macaque.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
AIM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0013-7227
pubmed:author
pubmed:issnType
Print
pubmed:volume
125
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1766-73
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1989
pubmed:articleTitle
Absence of regular pulsatile gonadotropin secretion during implantation in the rhesus macaque.
pubmed:affiliation
California Primate Research Center, University of California, Davis 95616.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.