Radiochromium distribution in hypophysectomized and adrenalectomized rats

The effects of hypophyseal and adrenal ablation (HYPOX, ADX) on trivalent radiochromium (51Cr) distribution and of GH and T4 replacement in HYPOX rats were determined. Hypophysectomy increased body retention of 51Cr by 20--35%, and hormonal replacement restored body retention to normal. Serum 51Cr was increased 300--800%, resulting in depressed tissue to serum 51Cr ratios. GH replacement partially restored the 51Cr distribution abnormalities in HYPOX rats to normal. The combination of T4 with GH enhanced the restoration of normal 51Cr distribution, and tissue to serum 51Cr ratios returned to baseline levels. ADX had no effect on body retention of 51Cr but had a small effect on increases in serum and tissue 51Cr levels. As a result, tissue to serum 51Cr ratios did not change. These data indicate that in the HYPOX state there is a marked disturbance in Cr metabolism which is due to deficiencies of both GH and T4. Whether or not adrenal hormones are envolved in 51Cr distribution will require further study.