InhBP/p120 transcripts in mouse pituitary gland. Northern blot analyses indicate the presence of four major InhBP/p120 RNA species in adult mouse pituitary. (A) A probe directed against the open reading frame of the rat InhBP-S gene detected transcripts of 4.4 (InhBP-L, top arrow), 2.7 (mInhBP-3, middle arrow), and 1.8 (InhBP-S, bottom arrow) kb. (B) A 204-bp probe corresponding to exon 13b detected a transcript of 2.7 kb (mInhBP-3, arrow). The asterisk indicates the InhBP-L transcript that was incompletely stripped from a previous hybridization. (C) A probe directed against 3′ sequences in exons 18 through 20 detected transcripts of 4.4 (InhBP-L, top arrow) and 2.7 (mInhBP-4, bottom arrow) kb. RNA molecular size standards (in kilobases) are indicated at the left of the figure.