ABSTRACT
The expression of rho family along the crypt-villus axis of rat small intestine was investigated. The immunoblot analysis showed that the content of rac1 protein gradually increased from tip-villus to crypt-villus enterocytes without changes in the contents of rhoA and rac2 proteins. Furthermore, the contents of rac1 protein in the entire enterocytes were markedly decreased in streptozotocin-induced diabetic rats and restored by short-term treatment with insulin. These results suggest that differentiation and proliferation in the enterocytes of rat small intestine are possibly related to the expression of rac1 protein through insulin action.
Subject(s)
GTP-Binding Proteins/metabolism , Insulin/physiology , Intestine, Small/metabolism , Animals , Blotting, Western , Diabetes Mellitus, Experimental/metabolism , Male , Rats , Rats, Wistar , rac GTP-Binding ProteinsABSTRACT
Mono(ADP-ribose) synthetase activity in the nuclear fraction of immature rat testis was investigated in reference to the effect of testosterone. When the nuclear fraction was incubated with [32P] NAD in the presence of nicotinamide, an inhibitor of poly (ADP-ribose) synthetase, some proteins with a molecular mass of 14.4-21.5 kDa were ADP-ribosylated. In these proteins, H2B and H3 histones were found by sequencing 20 amino acids in the N-terminus. Their incorporations of ADP-ribose moiety were significantly decreased in immature rats at 4 hr after the subcutaneous injection of testosterone. Furthermore, the treatments with LH and FSH of the immature rats reduced mono(ADP-ribosyl)ations of H2B and H3 histones in a time-dependent manner. These results suggest that the testicular mono(ADP-ribose) synthetase activity is under the control of gonadotropin-testosterone system and is possibly related to differentiation of the testis.
