Renin-Like and Cathepsin D Activities in Bovine Pineal Glands

Abstract

Pineal extract is shown to contain both renin-like and cathepsin D activities. Evidence of renin-like activity in the bovine pineal gland was brought by incubation with natural and synthetic renin substrates and by inhibition by pepstatin. Cathepsin D activity was demonstrated by incubation with hemoglobin and synthetic ñuorogenic peptide. The separation of both activities was performed by affinity chromatography on a caseinyl-Sepharose gel. The elution of the extract on affinity chromatography allowed to separate the renin-like activity, which is not retained by the gel at acid pH, from cathepsin D activity, which binds to the column at acid pH and is eluted at alkaline pH. The isolated pineal renin-like activity was found higher on tetradecapeptide renin substrate than on angiotensinogen at pH 5.5. The pH dependence of pineal renin-like activity showed two peaks of activity. One broad peak between pH 6 and 8 and one sharp peak at pH 3.5–4. These results demonstrate the existence of renin-like and cathepsin D activities in bovine pineal gland. They suggest moreover that the renin-like activity measured might represent a mixture of at least two different enzymatic activities.

Renin-Angiotensin System-Regulating Aminopeptidase Activities Are Modified in the Pineal Gland of Rats with Breast Cancer Induced by N-Methyl-Nitrosourea

“…Thus, the synthesis of angiotensinogen, the only common precursor of all known angiotensins, has been demonstrated to occur not only in various brain regions but also in the pineal gland (15). Furthermore, the pineal gland contains very high amounts of renin-like activity and angiotensin-converting enzyme (ACE), which converts angiotensin I (Ang I) to Ang II (7,(16)(17)(18). Ang III is produced from Ang II by AspAP and GluAP activities.…”

Locally synthesized angiotensin modulates pineal melatonin generation

“…1985; Haulica et al . 1975; de Agostini et al . 1982) and angiotensin‐converting enzyme (Nahmod et al .…”

“…The synthesis of AOGEN, the only common precursor of all known angiotensins, has been demonstrated to occur in various brain regions (Morgan et al 1996;Baltatu et al 1998a), including pineal gland (Baltatu et al 1998b) and to be mainly restricted to astroglia (Deschepper et al 1986;Stornetta et al 1988;Sernia et al 1997). Furthermore, the pineal gland contains very high amounts of renin-like activity (Mizuno et al 1985;Haulica et al 1975;de Agostini et al 1982) and angiotensin-converting enzyme (Nahmod et al 1982). We previously observed that the pineal converts Ang I to Ang II more readily than any other brain region (Baltatu et al 1997).…”