Search

The kinetic and thermodynamic properties of N-acetyl-β-D-glucosaminidase A (Hex A) and N-acetyl-β-D-D-glucosaminidase β (Hex B) from goat testes were investigated in free and bound (after binding them on ion-exchangers such as DEAE- or CM-cellulose respectively) forms. The optimum pH of free Hex A and Hex B was at 4.2 and 5.4, whereas the bound forms showed the optimum pH at 4.0 and 5.2 respectively. While apparent Km of free and bound Hex A (0.8 and 1.0 mM respectively) did not differ, the Km of Hex B increased when bound on CM-cellulose (Km of free Hex B = 0.96 mM versus bound Hex B = 1.6 mM). Though the free Hex A was more thermo-labile than the free Hex B, both isozymes, on insoluble matrices decayed at faster rates on heating. Activation analysis revealed that the energy of activation (E infa supo ) for transition state of free Hex B (81 Kcal deg−1 mole−1) did not differ from E infa supo of bound Hex B. On the other hand, E infa supo of free Hex A declined from 77.2 to 71.1 Kcal deg−1 mole−1 when heat transitions were carried out in free and bound state respectively. Thermodynamic analysis suggested a change in entropy of activation (ΔS*) of free Hex A and Hex B as 200 and 211 eu respectively. While ΔS* of Hex B did not change after heat transitions, ΔS* of Hex A was 182.5 eu.

Immunocytochemical localization of hexosaminidase activity in human males revealed that the enzyme activity is localized mainly in the Sertoli cells and interstitial tissue of the testis and in the columnar cells of the epididymis. In seminal vesicles, activity was observed around the glandular epithelium in the form of fine granules.

The decrease in the uptake of 65-Zn by irradiated testes (720 R) was followed by recovery after 30 days. After a dose of 2000 R, uptake of 65-Zn was systemtically reduced over a period of 74 days. Studies following the administration of testosterone and FSH germinal cells of the testes is under the control of pituitary gonadotrophins.

Bioelectrical activity of rat brain was studied after administration of endosulfan (5 mg/kg, ip) for 10 days. The pesticide produced rhythmic bursts of spikes and waves of seizure pattern that started 25-30 minutes after dosing and persisted for 60-minutes. The clonic convulsions were more marked over the head region and were mainly localized in the upper extremities. Histopathologic examination of the liver showed congestion of the central veins and its adjacent sinusoids. Concentration of the compound in brain parallelled the electrical activity.

Kinetic properties such as Michaelis constant (Km), maximum velocity (Vmax), temperature coefficient (Q10) and energy of activation (Ea) for hydrolysis of adenosine-5'-phosphate at pH 9.5 and sodium pyrophosphate at pH 8.35 by normal and radiated testes supernatants have been described. Kinetic parameters are related to respective phosphohydrolases (phosphatases). (1) Km values for 5'nucleotidase and inorganic pyrophosphatase of normal testis were determined as 1.25 X 10(-3)M and 0.81 X 10(-3)M respectively; (II) Vmax correspond to 318 mug P/15 min and 430 mug P/15 min for 100 mg tissue respectively; (III) Q10 for 5 nucleotidase is 1.7 and for inorganic pyrophosphatase is 4.2 at a temperature 10-30degreesC; (IV) Ea for hydrolysis of AMP and sodium pyrophosphate were calculated by Arrhenius plots as 17000 and 9000 cal/mol. (V) Km values for irradiated enzymes are similar to the control values suggesting that the binding capacities of these enzymes with their substrates remain unaffected after radiation; (VI) Vmax for radiated enzymes correspond to a value of 500 mug P/100 mg tissue/15 min for 5'nucleotidase and 118 mug P/100 mug tissue/15 min for inorganic pyrophosphatase; (VII) 110 for 5'nucleotidase is 2.2 and inorganic pyrophosphatase 1.16 at 10-30degreesC; (VIII) Ea for irradiated 5'nucleotidase is comparable to those of normal rats whereas for inorganic pyrophosphatase Ea is moderately declined. The observed changes have been related to the different types of metabolic activity in germinal and nongerminal cells of testes.

Oxidative enzymes in the rat testes have been studied after gamma irradiation. The role of these enzymes in relation to spermatogenesis and steroidogenesis after radiation injury to testis has been discussed. Loss of succinic dehydrogenase and sorbitol dehydrogenase reflects the losts of germ cell population. Malic enzyme and malic dehydrogenase seem to the related to the deficiency of steroid hormones, whereas increase in glucose-6-phosphate dehydrogenase and NADP isocitric dehydrogenase is due to secondary stimulation of pituitary.

Effects of partial body gamma irradiation have been studied on rat testis at lethal (2000 R) and sublethal (720 R) doses. Radiation produced a progressive decline in DNA and RNA content of testis for first 15 days at both lethal and sublethal doses, followed by recovery as evidenced up to 74 days without any evidence for recovery of spermatogenesis. The incorporation of P-32 into nucleic acids was also low as compared to normal rats on day 8 postirradiation. Subsequently there was a tendency for the enhanced incorporation of P-32 in nucleic acid fractions. The P-32 nucleic acids specific activities were higher on 74th day in radiated rats than in normal controls. Enhanced incorporation of P-32 in nucleic acids and phospholipid fractions after 15 days of irradiation indicates greater synthetic activity of testicular interstitium rather than in recovery of germ cells.

Hyaluronidase from rhesus monkey testes was purified by detergent extraction, ammonium sulphate fractionation, Sephadex G-200 column chromatography and concanavalin A-Sepharose affinity chromatography. The purified hyaluronidase showed one protein band on acrylamide gel electrophoresis. Antibodies to the purified hyaluronidase were raised in rabbits and showed a single precipitin line by Ouchterlony gel diffusion. The enzyme had a molecular weight of 62,000. The Km was 0.5 mg/ml for hydrolysis of hyaluronic acid at 37 degrees C. The optimum pH for the enzyme was 5.0 but activity was present over a broad pH range. The hyaluronidase was inhibited by HgCl2, CuSO4, FeSO4 and p-chloromercuribenzoate all at a concentration of 2 x 10(-4) M. Cysteine protected the enzyme against HgCl2 inhibition.

Environmental factors such as diet, climate, geographical factors, and fluid intake have an important role in the etiology of urolithiasis (1). Circadian rhythmicity in the urinary volume and excretion of creatinine (Cr), oxalate (Ox), glycolic acid, phosphate (Pi), uric acid (UA), sodium, potassium, chloride, and 17-keto steroids have been reported in healthy adults. Cohorts of stone formers who belong to the same ethnic group, share the same food habits, and are exposed to similar climatic conditions may be equally susceptible to stone disease which, possibly, may be present in the form of subtle biochemical changes. The present study investigates the circadian fluctuations in stone formers and cohorts of stone formers in an endemic area in northwestern India.

Degeneration of testis has been observed after administration of Iodine-125 in potassiumperchlorate treated rats. Histological damage is associated with loss of DNA, RNA, acid phosphatase, total adenosine triphosphatase (ATPase) and Na/K dependent ATPase. Iodine-125 induced atrophic testis shows higher content of sodium and lower levels of potassium as compared to control testis. Damage of testis by Iodine-125 has been compared with atrophied testis, following gamma irradiation earlier reported. Auger effect due to Iodine-125 decay and transmutation at the sites of nuclei and plasma membrane of germinal cells seems to be the possible explanation for testicular damage caused by Iodine-125.

The effect of gossypol acetic acid, a potent male sterilent was studied on LDH from goat liver (LDH-A4), heart (LDH-B4) and testis (LDH-C4) in vitro. All the preparations of LDH were inhibited by gossypol when the reaction was carried out in pyruvate-lactate (direct) or lactate to pyruvate (reverse) directions. The IC50 of gossypol for the pyruvate oxidation by LDH isozymes varied between 16 and 42 microM in presence of 0.27 mM pyruvate and 0.15 mM NADH at 25 degrees C and pH 7.4 whereas for the lactate oxidation, IC50 was 125 microM in a system containing 3.3 mM lactic acid and 1.8 mM NAD at 25 degrees C and pH 9.0. Reciprocal plots due to Lineweaver-Burk showed that these isozymes are inhibited in a non-competitive manner with respect to pyruvate and lactate, and in a competitive fashion when NAD and NADH were varied as substrates. Ki values of LDH-A4, -B4 and -C4 isozymes in presence of gossypol were 20, 34 and 29 microM against pyruvate; 33, 43 and 45 microM against NADH; 85, 85 and 125 microM against lactate and 94, 108 and 83 microM against NAD respectively.

Chemistry Department, Aligarh Muslim University S. V. College, Aligarh Received 19 October, 1971 Chemical Investigation of Chenopodium ambrosioides.

Glucose 6-phosphate dehydrogenase activity has been studied in testes following partial-body gammma irradiation. The activity of glucose 6-phosphate dehydrogenase per unit weight of wet testes and per milligram of protein was stimulated five- to six-fold over the sham-irradiated controls after exposures to 720 and 2000 R. The stimulation of the enzyme per testis was more evident at 720 R than at 2000 R. Most of the enhanced activity of the enzyme was localized in interstitial cells. When actinomycin D was administered 24 hr after irradiation, the enhanced activity of glucose 6-phosphate dehydrogenase could be suppressed considerably on Days 15 and 30 after irradiation. However, when increasing doses of actinomycin D were administered 18 hr before the sacrifice of rats on Day 27, it was observed that only 30% of the radiation-induced activity of the enzyme could be abolished. Following administration of low doses of testosterone (0.7 mg x 5/rat), glucose 6-phosphate dehydrogenase was reduced significantly in the sham-irradiated rats although such a response was not seen in the irradiated rats. However, larger doses of testosterone (2.5 and 5.0 mg x 16-18/rat) reduced the activity of glucose 6-phosphate dehydrogenase in testes of both sham-irradiated and irradiated rats significantly. Based on thesemore » studies it is suggested that the increase in the activity of glucose 6-phosphate dehydrogenase in testes is due to secondary stimulation of the pituitary after testicular irradiation. However, glucose 6-phosphate dehydrogenase also appears to be under local control in testes. The role of glucose 6-phosphate dehydrogenase in hyperplasia of testicular interstitium has been indicated.« less

Effect of radiation on enzymes of carbohydrate metabolism has been studied. It is observed that hexokinase of testis is highly sensitive to radiation damage. Reduced hexokinase activity seems to be related to those parts of the testis (spermatocytes and spermatids) which depend upon glucose for their functioning. Radiation-induced atrophic testis is rich in glycogen content. The observations on the inhibition of gluocose-6-phosphatase and phosphorylase may explain the higher levels of the polysaccharide although a possibility of enhanced glycogenesis due to the activation of glycogen synthetase has also been suggested. The presence of glucose-6-phosphate isomerase and glycogen in atrophied testis in 11-month-treated rats indicate the higher glycolytic activity with hyperplastic testicular interstitium. The results suggest that the accumulated glycogen is acting as a reserve substrate in nongerminal cells.

The effects of partial-body γ irradiation on the content of sodium, potassium, acid deoxyribonuclease, and adenosine triphosphatase (ATPase) of rat testes were studied. It was observed that the potassium content of the testis was reduced 24 hr after irradiation and remained depressed throughout the observation period. In the case of sodium, a decrease over the first 1-4 days was followed by a recovery to normal level and a subsequent rise on day 6 after 2000 R. However, after 720 R, the rise in sodium could be observed as early as 24-hr postirradiation and persisted for 37 days. A maximal loss of 70-85% in the content of potassium per testis occurred on day 10 after 2000 R and on day 16 after 720 R. Along with the changes in sodium and potassium in the testis after irradiation, there was an increase in acid deoxyribonuclease after 720 and 2000 R. ATPase was decreased up to 15 days postirradiation after exposure to 720 R. It was observed that normal testicular ATPase was stimulated by Na+/ K+ whereas irrad...

Studies on inorganic pyrophosphatase and pyrophosphate of rat testes have been carried out after partial- and whole-body ..gamma.. irradiation of rats. Inorganic pyrophosphatase was diminished 18-20 hr after partial-body irradiation at 2000 R; the decline per milligram of protein continued up to 74 days with minimum values on days 10 and 24, respectively, after 2000- and 720-R exposures. When values were expressed per testis, however, the minima were observed on days 26 and 37 postirradiation, respectively, for the same exposures. The decreased levels of inorganic pyrophosphatase were accompanied by accumulation of pyrophosphate up to day 26 but with a maximum value on Day 10. The loss of inorganic pyrophosphatase is a more sensitive index for radiation injury of testes than is the loss of testis weight and loss of nucleic acids content. The loss of inorganic pyrophosphatase could be visualized at the nuclear and cytoplasmic levels after differential centrifugation. After whole-body irradiation at 720 R, the loss of inorganic pyrophosphatase was seen in liver, kidney, epididymis, and testes. The changes of inorganic pyrophosphatase and pyrophosphate were found to be associated with degenerative changes of testicular cells. It is concluded that further degeneration of testes is caused by accumulation of pyrophosphatemore » which may be related to the reversal of several synthetic reactions in the germinal cells.« less

The effect of gamma radiation on NAD- and NADP-linked isocitrate dehydrogenases of testes results in a biphasic response both after lethal and sublethal exposures of 2000 and 720 R. The initial decrease in the activity of these enzymes seems to be associated with both germ and nongerm cells whereas the recovery of the two enzyme activities at a later stage seems to be associated with the hypertrophy of interstitial tissue. The biphasic response of NADP-linked isocitrate dehydrogenase following irradiation has been related to the androgen synthesizing capacity of irradiated testes. NADP-linked isocitrate dehydrogenase is inhibited in both sham-irradiated and irradiated testes after administration of testosterone under various conditions of radiation injury, suggesting that testicular NADP-isocitrate dehydrogenase is under the control of pituitary gonadotrophins. However, independent action of actinomycin D and testosterone propionate in conjunction with irradiation also indicate that mechanisms exist in testes which control the NADP-linked enzyme by local factors.