Substance P and neurotensin: Opposite effects on plasma cholesterol levels in ovariectomized conscious rats

Summary Intravenous pulse injection of neurotensin produces a significant and dose-dependent increase in plasma cholesterol levels in ovariectomized conscious rats, whereas substance P has opposite effect. 4-Aminopyrazolo (3,4,-d) pyrimidine, (4-APP) also significantly lowers plasma cholesterol. The suppressive effects of both substance P and 4-APP were readily reversed by neurotensin, suggesting that the peptides act on hepatic lipoprotein secretion.Supported by grants from the Indian Council of Medical Research (ICMR), New Delhi. K.R. was recipient of a UGC fellowship.