Vj. Roberts et al., HYBRIDIZATION HISTOCHEMICAL AND IMMUNOHISTOCHEMICAL LOCALIZATION OF INHIBIN ACTIVIN SUBUNITS AND MESSENGER RIBONUCLEIC-ACIDS IN THE RAT-BRAIN, Journal of comparative neurology, 364(3), 1996, pp. 473-493
Inhibin and activin are best known as gonadal glycoprotein hormones bu
t have a broad anatomical distribution. We previously described the ce
ntral distribution ofinhibin/activin beta A- and beta(B)-subunit prote
ins in some neuronal cell bodies, fibers, and nuclei of the rat brain
and reported a possible role for central activin in suckling-induced o
xytocin secretion and corticotropin releasing factor release. In the p
resent report, we mapped the detailed immunohistochemical localization
of inhibin/activin alpha-, beta(A)-, and beta(B)-subunits throughout
the rat brain to further clarify their central distribution. In additi
on, the localization and distribution of their corresponding mRNAs was
assessed. The results are summarized as follows: 1) Both beta(A)- and
beta(B)-subunit immunoreactivity are found in neuronal cell bodies in
the nucleus of the solitary tract and the dorsal and ventral medullar
y reticular nuclei, and in fibers and terminals of known projection si
tes for these nuclei. 2) beta(B)-subunit immunoreactivity is localized
in a group of perifornical neurons in the hypothalamus. 3) beta(A)-su
bunit immunoreactivity is present in discrete populations of neuronal
cell nuclei scattered throughout the CNS. 4) mRNAs encoding each of th
e inhibin/activin subunits are expressed in all major brain regions as
determined by S1 nuclease assay and in a variety of specific neuroana
tomical sites as shown by in situ hybridization. The results suggest t
hat central inhibin and activin proteins are produced in the brain whe
re they may potentially serve inter- and intracellular functions in mu
ltiple systems. (C) 1996 Wiley-Liss, Inc.