Linked Life Data

1425434

Source:http://linkedlifedata.com/resource/pubmed/id/1425434

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
5
pubmed:dateCreated
1992-12-1
pubmed:abstractText
The in vitro effects of insulin-like growth factor-I (IGF-I), insulin-like growth factor-II (IGF-II), truncated IGF-I, insulin, and human GH (hGH) on premitotic and premeiotic DNA synthesis of adult rat germ cells in vitro were investigated. Two-millimeter segments of seminiferous tubules from four different stages containing type A4-spermatogonia (stage I), type B spermatogonia (stage V), resting preleptotene spermatocytes (stage VIIa), and preleptotene spermatocytes in the S-phase (stage VIII-IX), respectively, were isolated by transillumination-assisted microdissection. They were cultured in serum-free medium at 34 or 37 C with and without growth factors, labeled for 4 h with tritiated thymidine, and harvested at 24, 48, and 72 h. Spontaneous progression of spermatogenesis was noted at both incubation temperatures, with a more rapid rate at 37 C. IGF-I significantly stimulated [3H]thymidine uptake in originally stage I and stage V tubule segments (type A4 and B spermatogonia, respectively) after 48 h of culture at 37 C. Improved maintenance of the DNA synthesis of stage VIII-IX tubules was found after 48 h at 37 C and 72 h at 34 C. Truncated IGF-I produced a similar response, but was more potent. IGF-II showed slight stimulation of stage V tubules after 72 h at both 34 and 37 C and maintenance of stage VIII-IX tubules after 48 h at 37 C and 72 h at 34 C. hGH was effective only at 34 C, showing slight stimulation of stage I tubule segments after 48 and 72 h of incubation. Insulin at high concentrations was effective only at 37 C and stimulated DNA synthesis in stages I, V, and VIIa after 48 h and stages V and VIIa after 72 h of incubation. It is concluded that IGFs stimulate premitotic DNA synthesis of rat germ cells in vitro and may also maintain premeiotic DNA synthesis. Whether the slight response to hGH is mediated via local production of IGF-I by the tissue cultures remains to be investigated. As IGF-I and IGF-II are locally produced in the testis, the present results suggest that these factors have a selective paracrine or autocrine role in the regulation of spermatogonial proliferation during spermatogenesis.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
AIM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Nov
pubmed:issn
0013-7227
pubmed:author
pubmed:issnType
Print
pubmed:volume
131
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
2344-50
pubmed:dateRevised
2011-11-17
pubmed:meshHeading
pubmed:year
1992
pubmed:articleTitle
Insulin-like growth factors selectively stimulate spermatogonial, but not meiotic, deoxyribonucleic acid synthesis during rat spermatogenesis.
pubmed:affiliation
Department of Pediatrics, Karolinska Hospital, Stockholm, Sweden.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't