Fig. 3. B4B2A5m mice dwarfism is GH- and T3/T4- independent. (A,B) X-Gal detection of lacZ expression in pituitary (200 µm section, A) and whole thyroid gland (B) of adult B4B2lacZ mice. lacZ is strongly expressed in many cells of the pituitary anterior lobe (AL), but less so in scattered cells of the intermediate (IL) and posterior lobe (PL). (C) Northern blot analysis of GH mRNA expression in control (CTRL) and transgenic B4B2A5m male mice. No significant difference in GH mRNA concentration is observed between control (n=4) and transgenic mice (n=4). GH mRNA was normalized using the S26 probe (see Materials and Methods). (D) RIA measurements of circulating GH in control (CTRL males, n=8; CTRL females, n=4) and transgenic B4B2A5m (TG males, n=8; TG females n=5) mice. No significant difference could be seen in GH concentration between transgenic and control mice. (E) RIA measurement of total T3 and T4 thyroid hormones in control and transgenic mice of both sexes (n=6 for all groups). Transgenic mice present no alteration in levels of circulating thyroid hormones. All experiments shown in this figure were performed at 3.5 weeks of age.