Differential expression of inhibin alpha and beta A subunit genes in rat and mouse ovarian follicles during pregnancy.
Relative levels of rat ovarian alpha inhibin (alpha I) and beta A inhibin (beta AI) mRNAs were measured during pregnancy by dot-blot hybridization of ovarian poly(A+) RNA. Follicular patterns of alpha I and beta AI expression in contralateral ovaries from the same rats were also studied by hybridization histochemistry. Oligodeoxynucleotide probes specific for porcine alpha I and beta AI were synthesized, 32P end-labelled and used as hybridization probes on dot-blots of ovarian RNA and frozen sections of ovarian tissue from pregnant rats. During pregnancy, levels of alpha I and beta AI mRNAs remained fairly constant from day 7 after mating until parturition and then fell within 16 h post partum. In all ovaries observed, expression of inhibin genes was located in granulosa cells of healthy antral follicles. In general, the strongest signals for alpha I and beta AI mRNAs were obtained in large follicles, with weaker signals in smaller follicles. Follicular patterns of alpha I and beta AI expression during pregnancy were often dissimilar when alpha I and beta AI were compared over a range of follicles. Considerable alpha I mRNA was detectable in some follicles in which beta AI was reduced or undetectable, despite strong signals for both alpha I and beta AI in an adjacent follicle. Essentially, alpha I mRNA levels were relatively consistent between groups of follicles, whereas beta AI levels varied considerably. beta AI mRNA was never observed in a follicle in the absence of alpha I mRNA, indicating that activin production in any follicle occurs in the presence of alpha I mRNA.(ABSTRACT TRUNCATED AT 250 WORDS)
Penschow
J D
JD
Howard Florey Institute of Experimental Physiology and Medicine, University of Melbourne, Parkville, Victoria, Australia.
Aldred
G P
GP
Darling
P A
PA
Haralambidis
J
J
Hammond
V E
VE
van Leeuwen
B H
BH
Mason
A J
AJ
Niall
H D
HD
Seeburg
P
P
Coghlan
J P
JP
D000818:Animals; D015152:Blotting, Northern; D005260:Female; D015870:Gene Expression; D005796:Genes; D006107:Granulosa Cells / Q000378:metabolism; D007265:Inhibins / Q000235:genetics*; D051379:Mice; D006080:Ovarian Follicle / Q000378:metabolism*; D010053:Ovary / Q000378:metabolism; D011247:Pregnancy; D011270:Pregnancy, Animal / Q000378:metabolism*; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D011919:Rats, Inbred Strains; D013997:Time Factors
D012333:RNA, Messenger; D007265:Inhibins