Matches in SemOpenAlex for { <https://semopenalex.org/work/W2055201103> ?p ?o ?g. }
- W2055201103 abstract "The acute and the long-term (24 h) effects of protein kinase C activators, phorbol 12 myristate 13-acetate (PMA) and 1-oleoyl-2-acetyl-sn-glycerol, and the calcium ionophore A23187 on cultured pig Leydig cell functions were investigated. None of these drugs modified basal cAMP production, but they induced a small (3-4-fold) increase in testosterone secretion. The stimulatory effects of human choriogonadotropin (hCG; 1 nM) on both cAMP and testosterone productions were inhibited by short-term incubation with these drugs. In addition, they suppressed the stimulation of testosterone output by forskolin and 8-bromo-adenosine 3',5'-monophosphate, whereas the forskolin-dependent cAMP production was unaffected. The inhibitory effects of PMA on hCG stimulation of both cAMP and testosterone were due mainly to a decrease of the Vmax without modification of the ED50. Moreover, PMA did not modify the binding of 125I-hCG. Pretreatment of Leydig cells with the three drugs for 24 h induced more pronounced modifications, such as a reduction in the number of hCG binding sites and a decreased responsiveness to hCG and forskolin, the testosterone production being drastically reduced. The effects of PMA were dose- and time-dependent; however, the concentration of PMA required to induce half-maximal effects on hCG receptors (10 nM) was about one order of magnitude higher than those required to reduce cAMP and testosterone productions. Further, the inhibitory effects on cAMP and testosterone secretions appeared within the first 3 h, whereas the hCG receptor number remained constant for at least 8 h. It appears therefore, that the main alteration responsible for the steroidogenic refractoriness of PMA-treated Leydig cells is located beyond cAMP formation. Moreover, since conversion of exogenous pregnenolone to testosterone by control and PMA-treated cells was similar, the alteration was probably located before pregnenolone formation. Kinetic studies with 125I-hCG showed that the rate of internalization of the hormone-receptor complexes was similar in control cells and in PMA-treated cells, suggesting that the decline in receptor number observed in the latter group after an 8-h delay is not due to an increased rate of internalization nor to sequestration of the internalized receptors inside the cells. Since cycloheximide blocked the effects of PMA on hCG down-regulation, it is likely that the phorbol esters and 1-oleoyl-2-acetyl-sn-glycerol induce the synthesis of some proteins which blocked the recycling of internalized receptors. A similar hypothesis has been put forward recently to explain the hCG-induced down regulation.(ABSTRACT TRUNCATED AT 400 WORDS)" @default.
- W2055201103 created "2016-06-24" @default.
- W2055201103 creator A5014327776 @default.
- W2055201103 creator A5055263820 @default.
- W2055201103 creator A5075258877 @default.
- W2055201103 creator A5082177855 @default.
- W2055201103 date "1987-02-01" @default.
- W2055201103 modified "2023-10-17" @default.
- W2055201103 title "Stimulatory and inhibitory effects of protein kinase C activation and calcium ionophore on cultured pig Leydig cells" @default.
- W2055201103 cites W125565797 @default.
- W2055201103 cites W1484470130 @default.
- W2055201103 cites W1517163332 @default.
- W2055201103 cites W1519338212 @default.
- W2055201103 cites W1527015272 @default.
- W2055201103 cites W1530724292 @default.
- W2055201103 cites W1534416515 @default.
- W2055201103 cites W1553799143 @default.
- W2055201103 cites W1554120835 @default.
- W2055201103 cites W1566852849 @default.
- W2055201103 cites W1575295429 @default.
- W2055201103 cites W1584089270 @default.
- W2055201103 cites W1598059529 @default.
- W2055201103 cites W1620610430 @default.
- W2055201103 cites W1676815435 @default.
- W2055201103 cites W1775749144 @default.
- W2055201103 cites W1965154398 @default.
- W2055201103 cites W1969521519 @default.
- W2055201103 cites W1976449066 @default.
- W2055201103 cites W1980735131 @default.
- W2055201103 cites W1987345342 @default.
- W2055201103 cites W1997290852 @default.
- W2055201103 cites W1998977187 @default.
- W2055201103 cites W2001692359 @default.
- W2055201103 cites W2009115016 @default.
- W2055201103 cites W2017691305 @default.
- W2055201103 cites W2027913950 @default.
- W2055201103 cites W2030706296 @default.
- W2055201103 cites W2036054121 @default.
- W2055201103 cites W2049000383 @default.
- W2055201103 cites W2053489006 @default.
- W2055201103 cites W2055137307 @default.
- W2055201103 cites W2055308598 @default.
- W2055201103 cites W2056374369 @default.
- W2055201103 cites W2063088976 @default.
- W2055201103 cites W2064762154 @default.
- W2055201103 cites W2069579388 @default.
- W2055201103 cites W2085344344 @default.
- W2055201103 cites W2087582909 @default.
- W2055201103 cites W2106928904 @default.
- W2055201103 cites W2125890714 @default.
- W2055201103 cites W2132702380 @default.
- W2055201103 cites W2134615717 @default.
- W2055201103 cites W2144598823 @default.
- W2055201103 cites W2153151822 @default.
- W2055201103 cites W2182221722 @default.
- W2055201103 cites W4298306388 @default.
- W2055201103 doi "https://doi.org/10.1111/j.1432-1033.1987.tb10753.x" @default.
- W2055201103 hasPubMedId "https://pubmed.ncbi.nlm.nih.gov/3028794" @default.
- W2055201103 hasPublicationYear "1987" @default.
- W2055201103 type Work @default.
- W2055201103 sameAs 2055201103 @default.
- W2055201103 citedByCount "15" @default.
- W2055201103 crossrefType "journal-article" @default.
- W2055201103 hasAuthorship W2055201103A5014327776 @default.
- W2055201103 hasAuthorship W2055201103A5055263820 @default.
- W2055201103 hasAuthorship W2055201103A5075258877 @default.
- W2055201103 hasAuthorship W2055201103A5082177855 @default.
- W2055201103 hasBestOaLocation W20552011031 @default.
- W2055201103 hasConcept C126322002 @default.
- W2055201103 hasConcept C134018914 @default.
- W2055201103 hasConcept C170493617 @default.
- W2055201103 hasConcept C184235292 @default.
- W2055201103 hasConcept C185592680 @default.
- W2055201103 hasConcept C195794163 @default.
- W2055201103 hasConcept C24998067 @default.
- W2055201103 hasConcept C2776991684 @default.
- W2055201103 hasConcept C2777736315 @default.
- W2055201103 hasConcept C2778575703 @default.
- W2055201103 hasConcept C2779276759 @default.
- W2055201103 hasConcept C2779279991 @default.
- W2055201103 hasConcept C2780043322 @default.
- W2055201103 hasConcept C519063684 @default.
- W2055201103 hasConcept C55493867 @default.
- W2055201103 hasConcept C71315377 @default.
- W2055201103 hasConcept C71924100 @default.
- W2055201103 hasConcept C86803240 @default.
- W2055201103 hasConcept C97029542 @default.
- W2055201103 hasConceptScore W2055201103C126322002 @default.
- W2055201103 hasConceptScore W2055201103C134018914 @default.
- W2055201103 hasConceptScore W2055201103C170493617 @default.
- W2055201103 hasConceptScore W2055201103C184235292 @default.
- W2055201103 hasConceptScore W2055201103C185592680 @default.
- W2055201103 hasConceptScore W2055201103C195794163 @default.
- W2055201103 hasConceptScore W2055201103C24998067 @default.
- W2055201103 hasConceptScore W2055201103C2776991684 @default.
- W2055201103 hasConceptScore W2055201103C2777736315 @default.
- W2055201103 hasConceptScore W2055201103C2778575703 @default.
- W2055201103 hasConceptScore W2055201103C2779276759 @default.
- W2055201103 hasConceptScore W2055201103C2779279991 @default.
- W2055201103 hasConceptScore W2055201103C2780043322 @default.