The suppressive effect of protamine from chum salmon milt on lipid absorption in humans

Abstract

Protamine is a basic protein that is combined with DNA in the vertebrate sperm nucleus. It was reported that protamine purified from chum salmon milt has pancreas lipase inhibition activity (IC50 = 1.2 μg/mL). In the case of rats, protamine administration (100 mg/rat) showed a suppressive effect on the blood plasma triglyceride (TG) levels in the corn oil tolerance test. Here, we investigated the suppressive effect of our developed protamine, "Proserve", on lipid absorption in humans. The oral fat tolerance test (OFTT) was performed on normal adult male subjects as a single-blind test. The subjects were fed a high-fat meal containing 56.0g of lipid and 500 mg of protamine. Before and 2, 3, 4, 6 h after ingestion, TG and free fatty acid levels in blood were measured. Protamine significantly suppressed the elevations of the TG and free fatty acid levels in blood after ingestion of the high fat meal compared with the placebo group. When 300 mg of protamine was administered, no significant suppressive effect was confirmed, but TG and free fatty acid levels in the blood tended to be suppressed. In the digestive resistance test, the lipase inhibition activity of protamine was maintained after the reaction in the stomach. Therefore, we propose that protamine is an anti-obesity material.