Effects of adenosine analogs on glucagon-stimulated adenosine 3',5'-monophosphate formation in Sertoli cell cultures from immature rats.
In the present study, we have examined the effects of two adenosine analogs, (-)N6-(R)phenyl-isopropyl-adenosine (PIA) and 2-chloro-adenosine, on glucagon- and FSH-stimulated cAMP production in Sertoli cell cultures isolated from immature (19-day-old) rats. Both FSH and glucagon caused a 5- to 10-fold stimulation of cAMP levels in the spent media from Sertoli cell cultures during an 18-h incubation. Addition of 1 microM PIA significantly inhibited both FSH- and glucagon-stimulated cAMP levels. In the presence of a maximal concentration of glucagon (2.5 micrograms/ml), PIA caused a concentration-dependent inhibition of cAMP formation, and the concentration of PIA causing half-maximal inhibition of cAMP formation (IC50) ranged from 0.5-1 nM. When Sertoli cells were incubated with increasing concentrations of glucagon (1.28 ng/ml to 4.00 micrograms/ml) in the absence and presence of either PIA (1.0 microM) or 2-chloro-adenosine (10.0 microM), the responses to glucagon, measured as cAMP formation, were almost completely abolished. 1-Methyl-3-isobutylxanthine (MIX), a well known inhibitor of cAMP phosphodiesterase activity, is also an inhibitor of adenosine binding to receptors on the cell membrane. When Sertoli cells stimulated with glucagon (2.5 micrograms/ml) were incubated in the absence and presence of MIX (0.1 mM) and increasing concentrations of PIA (0.025-10,000 nM), the presence of MIX reduced the inhibitory activity of PIA by almost 2 orders of magnitude (IC50 without MIX, 0.5 nM; IC50 with MIX, 20 nM). Thus, the present study shows that adenosine analogs inhibit agonist-stimulated cAMP formation in cultured Sertoli cells, and that MIX reduces this effect. This indicates that cultured Sertoli cells from immature rats contain A1-receptors for adenosine mediating inhibitory effects on adenylate cyclase.
Eikvar
L
L
Levy
F O
FO
Jutte
N H
NH
Cervenka
J
J
Yoganathan
T
T
Hansson
V
V
D015762:2-Chloroadenosine; D000241:Adenosine / Q000031:analogs & derivatives* / Q000494:pharmacology; D000818:Animals; D002478:Cells, Cultured; D000242:Cyclic AMP / Q000096:biosynthesis*; D005640:Follicle Stimulating Hormone / Q000494:pharmacology; D005934:Glucagon / Q000494:pharmacology*; D007700:Kinetics; D008297:Male; D010660:Phenylisopropyladenosine / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D012708:Sertoli Cells / Q000187:drug effects / Q000378:metabolism*; D012741:Sexual Maturation
D015762:2-Chloroadenosine; D010660:Phenylisopropyladenosine; D005640:Follicle Stimulating Hormone; D005934:Glucagon; D000242:Cyclic AMP; D000241:Adenosine