**3. Statistical analysis**

The PRL concentration was calculated by linear regression and values of PRL concentration obtained by ELISA were averaged for each experimental group. Statistical differences were determined by a one-way analysis of variance (ANOVA), using Dunnett's test, and all treatments were compared versus the control (Earle's medium or Total PRL). Comparisons were analysed with the Graph Pad 5.0 Software, Inc. (San Diego, CA). The significance level was set at p<0.05. Each control or test compound was assayed in duplicate, and the assays were performed three times (n=3).

Autocrine and Paracrine Regulation of Prolactin Secretion

**Figure 1.(A-B).** SDS-PAGE (left panels) and prolactin (PRL) content (ng/μl) of PRL variants (middle and right panels) released from the peripheral (PR) and central (CR) adenohypophyseal

by Prolactin Variants and by Hypothalamic Hormones 103
