Failure to Demonstrate Anti-Hormonal Antibodies in Rats after Maximal Response to Daily Administration of Growth Hormone.

Abstract

Adult female Long-Evans rats were injected daily for 248 days with a growth hormone containing pituitary extract. These rats, after reaching a weight of 633 g (2.4 times control weight), attained a growth plateau with no further growth typical of rats receiving exogenous growth hormone. Normal adult (7 mo.) female Long-Evans assay rats were injected daily for 10 days with 10% of the daily extract dosage given the plateaued giant rats diluted in 8.5% of the average total body serum of the plateaued giant rats. The assay rats had a growth response which did not differ significantly from other groups of assay rats receiving the same extract dosage diluted in normal rat serum, saline solution or undiluted. Data are presented which show that the assay method would have readily detected attenuation of the growth promoting potency of the extract, had such occurred.