Antti Telkkä

QUANTITATIVE DETERMINATION OF SUCCINIC DEHYDROGENASE AS AN ESTIMATE OF THE FUNCTIONAL STATE OF THE RAT SEMINAL VESICLE

The seminal vesicles of the rat were stimulated by testosterone-treatment or depressed by castration. The activity of the gland was demonstrated using histoquantitative methods and by quantitative determination of the succinic dehydrogenase activity in the vesicles. There was a good correlation between the seven different variables reflecting the functional state of the vesicle. Quantitative estimation of succinic dehydrogenase of the vesicle seemed to be superior to the other methods because of its greater sensitivity. In a recent report (Hopsu, Kivikoski 8c Telkkä 1961) we demonstrated that quantitative estimated protein-bound sulfhydryl groups of the rat seminal vesicle can be used as a measure of the functional state of this gland. Succinic dehydrogenase, an enzyme involved in the tricarboxylic acid cycle of Krebs, is abundantly present in the epithelium of the seminal vesicle (Telkkä 8c Tuovinen 1954; Tuovinen 8c Rapóla 1956). This enzyme requires sulfhydryl groups for its activity. Furthermore, the results of a previous study dealing with the quantitative determination of succinic dehydrogenase as an indicator of the activity of another gland, the thyroid, (Telkkä et al. 1960) seemed to be en¬ couraging. Hence it seemed to be justifiable to try to correlate the quantita¬ tively determined succinic dehydrogenase activity of the seminal vesicle with its functional state. Aided by a grant from the Sigrid Jusélius Foundation. Downloaded from Bioscientifica.com at 11/23/2018 06:07:46PM via free access MATERIAL AND METHODS The material consisted of 27 male rats of the Long-Evans strain, weighing about 270 g. They were divided into three groups, the animals of the first group being castrated three weeks prior to termination of the experiment. The nine rats of the second group were injected with testosterone (Primoteston, »Schering«)1 in a dose of 2 mg twice a week over a period of two weeks. The third group of nine rats served as intact controls. The rats were fed with an ordinary laboratory diet and kept under identical conditions. After the experimental period, the rats were killed by decapita¬ tion and bled. The seminal vesicles were rapidly removed and weighed. Pieces of the vesicle were fixed in 10 per cent formalin, embedded in paraffin and after sec¬ tioning, stained with Mallorys azan method. From these specimens the percentage of the tissue components were determined using the line sampling method of Votila 8c Kaunas (1952). Other pieces of the vesicle were immediately frozen, cut at 30 μ with a freezing microtome and the succinic dehydrogenase activity was demonstrated according to Nachlas et al. (1957) using Nitro/BT as the final electron acceptor. From the remaining pieces of the vesicle a quantitative estimation of the enzyme was made following the directions of Villareal 8c Burgos (1955). The statistical analyses of the data obtained were performed according to Fisher (1954). RESULTS The histochemically demonstrable succinic dehydrogenase (SDH) activity in the seminal vesicle of one testosterone-treated and that of one castrated rat is depicted in Figs. 1-2. The difference in the enzymatic activity between Figs. 1-2. 1. Succinic dehydrogenase activity in the seminal vesicle of a testosterone-treated rat (about 200 X). 2. SDH activity in the vesicle of a castrated rat (about 200 X). 1. Kindly supplied by Leiras Oy, Pharmaceutical Manufacturers, Turku, Finland. Downloaded from Bioscientifica.com at 11/23/2018 06:07:46PM via free access