Regional differences in ribonuclease content of rat and mouse kidney

Abstract

Kidney cortex, red medulla and white medulla were separated into nuclei, mitochondria, microsomal and 105000g supernatant fractions. Assay of RNAase (ribonuclease) activity at pH7.8 revealed that, for each subcellular fraction, activity was much greater in cortex than in red or white medulla; this was true for both free RNAase and total (free plus latent) RNAase. For example, the free RNAase activity in the 105000g supernatant of cortex was 5 and 8 times higher than in red and white medulla respectively. No latent RNAase activity was found in any particulate fraction. Latent supernatant RNAase activities (suggesting presence of bound RNAase inhibitor) were similar in cortex and medulla. The cortex supernatant contained minimal free RNAase inhibitor, whereas that of the red and white medulla showed about one-third and one-tenth respectively of the inhibitor activity measured in liver. Adrenalectomy did not change RNAase activity in any fraction nor the content of free RNAase inhibitor in the kidney supernatant, but did decrease the liver RNAase inhibitor content by 40%. In supernatants from mouse kidney, both free and total RNAase activities of both cortex and red medulla were similar to those of rat red medulla. Mouse cortex contained appreciably higher amounts of free RNAase inhibitor than rat cortex. The difference between the rat and mouse cortical RNAase activity and inhibitor content may help explain the relative ease with which satisfactory renal polyribosome profiles were obtained from mouse kidneys. Our results, as well as those of Kline & Liberti [(1973) Biochem. Biophys. Res. Commun.52, 1271-1277], showing that renal red and white medulla are more active than cortex in protein synthesis, are consistent with the hypothesis that the RNAase-RNAase-inhibitor system may participate in the regulation of protein synthesis.

Ca2+-stimulated ribonuclease. A new marker enzyme of differentiated rat mammary tissues

“…These results, also expressed in ratios of the activity measured with and without Ca2+ ions as shown in Table 1, indicate that enzyme appears during late gestation when rapid differentiation and proliferation occur in the gland, and reaches a maximal activity when the gland is actively engaged in milk secretion. Allard, 1959;Nicholls et al, 1970;Liu & Matrisian, 1977), had the same activity whether or not Ca2+ ions were added to the assay, and similar results were obtained with kidney from virgin and lactating animals. In 1979 40.55±0.10 (3) 5.60±1.15 (3) 82.9 ±12.0 (4) 78.7 +8.7 78.80± 1.35 (3) 4.00…”

Ribonuclease activities in developing experimental granulation tissue with reference to polysomes

“…The cellular RNaselRNase-inhibitor system is thus involved in the regulation of protein synthesis (Kraft & Shortman 1970a. Liu et al 1975, Liu & Matrisian 1977, Blackburn et al 1977.…”

Περαιτερω Μελετη Της Δρασης Της Poly(u), Poly(c) Ριβονουκλεασης Απο Τις Προνυμφες 6 Ημερων Του Εντομου Ceratitis Capitata Και Μεταφραση Της Σε in Vitro Συστημα Πρωτεινοσυνθεσης

“…Στα ριΒοσώματα του E.Coli έχουν απομονωθεί δύο είδη ριΒονουκλεασών (180,181). Η μία εκ'των βύο, η RNaon Ι όπως ονομάστηκε, έχει υψηλή συγγένεια με το 70S ριΒόσωμα και παραμένει σε λανθάνουσα κατάσταση ενωμένη με αυτό.…”