Linked Life Data

3342931

Source:http://linkedlifedata.com/resource/pubmed/id/3342931

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
1988-4-6
pubmed:abstractText
The cells of the bean-shaped accessory glands of mealworms proliferate through the first 7 days of the 9-day pupal stage. Immediately after larval-pupal ecdysis, 25-27% of the cells were in the G1 phase, 60-65% were in the G2 phase, and the balance were in S phase. Over the first 4 days of normal development, the S fraction gradually increased, to reach its highest level in the mid-pupa at the time of the major ecdysteroid peak (Delbecque et al., 1978). Thereafter, the S fraction declined until over 95% of the cells had accumulated in G2 on Day 8. When 0-day pupal glands were explanted into Landureau's S-20 medium for 6 days, the G1 fraction remained fairly constant (25-30%) while S and the G2 fractions fluctuated. On the first day in vitro, the G2 fraction declined and the S fraction rose. On the second day in basal media, the S fraction fell and G2 rose correspondingly until 70% of the cells reached G2 when cycling stopped on the third day. With addition of 20-hydroxyecdysone to 0-day cultures, the S fraction increased quite sharply. It remained large for all 6 days of the experiment in the continuing presence of hormone. A 1-day pulse of hormone produced a transient increase in S. We blocked cell cycling with hydroxyurea in a stathmokinetic experiment and showed that 20-hydroxyecdysone accelerated the flow of cells from the G2 phase to the G1 phase by 2.5-fold. An increase in the G1 fraction was detected within 10 hr of hormone administration and the effect was dose-dependent with an ED50 of 5 X 10(-7) M for 20-hydroxyecdysone. We conclude that 20-hydroxyecdysone acts at a control point in the G2 phase. Incubation of the glands with 20-hydroxyecdysone for only 30-60 min followed by washout stimulated the flow from G2 to G1 and the effect persisted after transfer of the tissues to hormone-free media. Dose-dependent stimulation also occurred with ponasterone A (ED50 3 X 10(-9] but not with cholesterol.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
0012-1606
pubmed:author
pubmed:issnType
Print
pubmed:volume
126
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
173-81
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1988
pubmed:articleTitle
20-Hydroxyecdysone accelerates the flow of cells into the G1 phase and the S phase in a male accessory gland of the mealworm pupa (Tenebrio molitor).
pubmed:affiliation
Department of Zoology, University of Vermont, Burlington 05405.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.