Follicle-stimulating hormone-dependent estrogen secretion by rat Sertoli cells in vitro: modulation by calcium.
We have investigated the role of Ca2+ in the control of FSH-induced estradiol secretion by Sertoli cells isolated from 8-10 days old rats. Exogenous Ca2+ (4-8 mmol/l) inhibited FSH-stimulated E2 secretion such that, with 8 mmol/l Ca2+ and FSH (8 IU/l) E2 secretion decreased from 2091 +/- 322 to 1480 +/- 84 pmol/l (p less than 0.002), whilst chelation of Ca2+ in the culture medium with EGTA (3 mmol/l) increased E2 secretion from 360 +/- 45 to 1242 +/- 133 pmol/l) in the absence of FSH. Further, EGTA (3 mmol/l) markedly potentiated FSH (8 IU/l), forskolin (1 mumol/l) and dibutyryl cAMP (1 mmol/l)-stimulated E2 secretion. Addition of the Ca2+ ionophores, ionomycin (2-5 mumol/l) and A23187 (2 mumol/l), inhibited FSH (8 IU/l)-stimulated E2 secretion by greater than 80%. The effect of ionomycin was totally reversible, whereas that of A23187 was irreversible. Ionomycin (5 mumol/l) had no effect on EGTA-induced E2 secretion in the absence of FSH, but reduced EGTA-provoked E2 secretion by 59% in the presence of FSH (8 IU/l). Similarly, forskolin- and dibutyryl cAMP-provoked E2 production was inhibited 46-50% by ionomycin (5 mumol/l). We conclude that FSH-induced E2 secretion from immature rat Sertoli cells is modulated by intra- and extracellular Ca2+.
Talbot
J A
JA
Department of Medicine (Clinical Biochemistry), University of Manchester, Hope Hospital, Salford, UK.
Lambert
A
A
Mitchell
R
R
Grabinski
M
M
Anderson
D C
DC
Tsatsoulis
A
A
Shalet
S M
SM
Robertson
W R
WR
D000818:Animals; D003994:Bucladesine / Q000494:pharmacology; D000001:Calcimycin / Q000494:pharmacology; D002118:Calcium / Q000494:pharmacology; D002478:Cells, Cultured; D005576:Colforsin / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D004533:Egtazic Acid / Q000494:pharmacology; D004958:Estradiol / Q000096:biosynthesis; D004967:Estrogens / Q000378:metabolism*; D005640:Follicle Stimulating Hormone / Q000494:pharmacology*; D066298:In Vitro Techniques; D015759:Ionomycin / Q000494:pharmacology; D008297:Male; D011863:Radioimmunoassay; D051381:Rats; D011919:Rats, Inbred Strains; D012708:Sertoli Cells / Q000378:metabolism*
D004967:Estrogens; D005576:Colforsin; D000001:Calcimycin; D004958:Estradiol; D004533:Egtazic Acid; D015759:Ionomycin; D003994:Bucladesine; D005640:Follicle Stimulating Hormone; D002118:Calcium