The effects of semi- and HPLC-purified human satietin and alpha-1-glycoprotein on ingestion and body weight.

Satietin is thought to be an endogenous glycoprotein that can suppress food intake (FI) and body weight (b.wt.). In Experiment 1, rats were ICV infused with either a-CSF or with 50 micrograms/rat of human satietin. FI was suppressed (p less than 0.05) for 2 days after infusion, whereas b.wt. was attenuated (p less than 0.05) for 14 days. In Experiment 2, the previously thought homogenous human satietin was further purified by HPLC and this yielded two peaks (A and B). Rats were ICV infused with either a-CSF or 50 micrograms/rat of Peak A, Peak B or the semipurified parent human satietin (sph-SAT) from which the peaks were derived. All three treatments suppressed (p less than 0.05) FI on day 1 after infusion and on day 2 in the groups that received Peak A and sph-SAT. Body weight was attenuated (p less than 0.01) in all the experimental groups on day 1 and for 2 and 10 days, respectively, in the Peak A and sph-SAT-treated groups. Immunostaining revealed Peak A contained both albumin and alpha-1-glycoprotein (A1G), whereas Peak B contained neither. In the last experiment rats were ICV infused with either a-CSF or 50 micrograms/rat of A1G or A1G that was put through the sph-SAT extraction procedure. FI was suppressed (p less than 0.01) and b.wt. attenuated in both experimental groups only on the first day postinfusion. These data suggest that some, but possibly not all, of the previously found biological activity attributed to sph-SAT might be due to contaminants of the preparation.