Inhibin alpha, beta A and beta B subunit messenger ribonucleic acid levels in cultured rat pituitary: studies by a quantitative RT-PCR.
Recent studies have demonstrated that inhibins and activins both play not only endocrine roles but also local regulatory roles in gonadotoropin secretion. There has been controversy as to the subtype of rat pituitary inhibin/activin. We studied the levels of inhibin alpha, beta A and beta B subunit mRNAs by a quantitative reverse transcription-polymerase chain reaction (RT-PCR) and the changes in their levels by adding inhibin alpha, beta A and beta B mRNA antisense oligonucleotides and inhibin A, activin A or GnRH to cultured rat anterior pituitary cells. This study demonstrated the level of 3 mRNAs to be 1.6 x 10(-2), 0.75 and 3.4 x 10(-2) molecules/cell with a molar ratio of 1:50:2. A stimulatory role for activin B in FSH secretion was suggested as beta B mRNA antisense oligonucleotide decreased FSH secretion. The beta B mRNA level tended to be decreased by the addition of activin A, but the decrease was not statistically significant. GnRH did not affect alpha and beta B mRNA levels when administered singly. The level of beta A mRNA was not changed by any of the above treatments. In conclusion, the presence of inhibin alpha, beta A and beta B subunit mRNAs in the rat anterior pituitary with the greatest abundance of beta A was demonstrated by using RT-PCR. Activin B or activin AB may play important roles in FSH secretion in an autocrine or a paracrine fashion, and activin A may play an indirect role in FSH secretion.
Demura
R
R
Institute of Clinical Endocrinology, Tokyo Women's Medical College, Japan.
Suzuki
T
T
Yajima
R
R
Tajima
S
S
Kubo
O
O
Yoshimoto
T
T
Demura
H
H
D028341:Activins; D000818:Animals; D002478:Cells, Cultured; D005640:Follicle Stimulating Hormone / Q000378:metabolism; D007987:Gonadotropin-Releasing Hormone / Q000494:pharmacology; D007265:Inhibins / Q000494:pharmacology; D007986:Luteinizing Hormone / Q000378:metabolism; D008297:Male; D016376:Oligonucleotides, Antisense / Q000494:pharmacology; D010455:Peptides / Q000235:genetics*; D010903:Pituitary Gland, Anterior / Q000187:drug effects / Q000378:metabolism*; D016133:Polymerase Chain Reaction / Q000379:methods*; D029584:Prostatic Secretory Proteins; D012333:RNA, Messenger / Q000378:metabolism*; D012194:RNA-Directed DNA Polymerase; D051381:Rats; D017208:Rats, Wistar
D016376:Oligonucleotides, Antisense; D010455:Peptides; D029584:Prostatic Secretory Proteins; D012333:RNA, Messenger; C043076:beta-microseminoprotein; C094377:inhibin-alpha subunit; D028341:Activins; D007987:Gonadotropin-Releasing Hormone; D007265:Inhibins; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone; D012194:RNA-Directed DNA Polymerase