The Expression of the Kallikrein Gene Family in the Rat Pituitary: Oestrogen Effects and the Expression of an Additional Family Member in the Neurointermediate Lobe

Using a series of oligonucleotide probes (18 to 21 mers) specific for members of the rat kallikrein/tonin gene family (PS, S1, S2, S3, K1, P1), we have shown by Northern blot analysis that the oestrogen‐dependent kallikrein gene expressed in the male and female rat anterior pituitary is true kallikrein (PS). In addition, we have demonstrated that oestrogen treatment may also induce PS gene expression in the male and female rat neurointermediate lobe. None of the other five rat arginyl‐esteropeptidase genes so far described (S1, S2, S3, K1, P1) was found to be expressed in the anterior pituitary or neurointermediate lobe under these conditions. However, the demonstration of an additional hybridization signal in the male neurointermediate lobe using a relatively non‐specific PS gene probe suggests the expression of another, as yet uncharacterized, kallikrein gene family member in this tissue.