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K Guha

Publications and source records attributed to K Guha.

7 recordsLinked to original sources
PubMed1983

Acid phosphatases in the mouse testis: activity changes during development.

The histology and acid phosphatase activities of the developing testes in the mouse, from 4 days of age until maturity, were analyzed. The specific enzyme activity with p-nitrophenyl phosphate as substrate increased after 3 weeks of age and then reached a plateau. Cobalt and zinc markedly increased the specific activity after the third week. After fractionation the testicular homogenate revealed four acid phosphatases. Enzyme I maintained a high activity during the first 3 weeks but steadily declined thereafter. Enzyme II, present in all age groups, showed a moderate increase after the fourth week. Enzymes III and IV were low and declined further during the first 3 weeks with a subsequent increase. This occurred concomitantly with the appearance of spermatids and mature sperm cells. Changes in enzyme activities seem to reflect the alterations in cellular composition of the testis during the developmental process. Enzymes III and IV were probably associated with spermatids and sperm cells.

Acid Phosphatase↗
PubMed1982

Acid phosphatases of dog testis and a Leydig cell tumor.

Acid phosphatase activities were measured with five different substrates after fractionation with Sepharose 6B and DE-52 cellulose chromatography of homogenate from normal adult dog testis and a testicular tumor. The tumor showed a positive 3 beta-hydroxysteroid dehydrogenase reaction and was diagnosed as a Leydig cell adenoma. The fractionations gave three separate enzyme activities in the normal testis and two enzymes in the tumor. All were sensitive to sodium fluoride, but differed from each other in pH-optima and the response to Co2+ and Zn2+. Enzymes I and II were identical in both tissues. The latter with a smaller molecular weight was activated by Zn2+ but not by Co2+ and had slightly higher pH-optimum (4.5) than enzyme I (optimum at pH 3.5). The third enzyme was activated by Co2+ and Zn2+ and had the highest pH-optimum (pH 5.5). It was called enzyme IV due to its resemblance to a similar activity in other mammalian species.

Acid Phosphatase↗
PubMed1980

Testicular acid phosphatases in cattle, sheep, guinea pig, and rabbit.

Acid phosphatase activities were measured with five different substrates in the total homogenates as well as after gel filtration on Sepharose 6B and cellulose chromatography of bull, guinea pig, rabbit, and ram testes. The response of the hydrolysis rate to NaF (5 mmol/l), Co2+ (5 mmol/l) and Zn2+ (5 mmol/l) was also tested. In the total homogenate the hydrolysis of p-nitrophenyl phosphate was markedly activated by Co2+, while in the presence of Zn2+ an activation was recorded in guinea pig and some inhibition in the bull, rabbit, and ram testes. NaF caused a decline in the total acid phosphatase activity, particularly in guinea pig and ram. The gel filtration resulted in three separate activity peaks with p-NPP and beta-NP as substrates. N-ASBI-P, alpha-NP, and Tym-P gave only two peaks. After subsequent cellulose chromatography of the activities only peak II gave rise to two further activities. Peak I of gel filtration (enzyme I) was able to hydrolyze all substrates tested and was highly sensitive to NaF. Peak I of cellulose chromatography (enzyme II) also hydrolyzed p-NPP and beta-NP. It was rather resistant to NaF but sensitive to Zn2+. It was slightly activated by Co2+. Peak II of cellulose chromatography (enzyme IV) hydrolyzed only p-NPP and was markedly activated by Co2+ and Zn2+. The adult testes of bull, guinea pig, rabbit, and ram have a closely similar testicular acid phosphatase pattern. Due to relative differences in the concentrations of the four enzymes in the tissue, varying activity levels are recorded in the presence of different substrate and modifier combinations.

Acid Phosphatase↗
PubMed1979

Testicular acid phosphatases of the mouse. Characterization after chromatographic fractionation.

The testicular homogenate of adult mice was eluted by DEAE-cellulose chromatography. Four peaks of acid phosphatase were identified. The pooled samples of each peak were used to determine substrate specificity, pH-optima, modifier characteristics, thermal stability, and Km-values. The results obtained suggest that each peak may represent a separate and distinct type of acid phosphatase. These observations are very similar to those previously obtained with the rat testis. The acid phosphatase activities in the mouse seem, however, to differ biochemically to some extent from those in the rat.

Acid Phosphatase↗
PubMedDate not supplied

Acid phosphatases in the human testis after prolonged estrogen treatment.

The testes of 2 autopsied adult men and 6 subjects, suffering from prostatic carcinoma, were analysed for acid phosphatase activities, Two of the prostatic patients had been receiving estrogen treatment at least for a year and had completely regressed testes. Testes of other subjects contained well-defined tubules with different spermatogenic cells in abundance. The total acid phosphatase activity, assayed in the homogenate, showed a marked reduction in the testes of estrogen-treated subjects. Enzymes were separated by cellulose chromatography or by gel filtration combined with cellulose chromatography. Three activity peaks were resolved by the former and four by the latter technique, when homogenates of the control testes were used. In contrast, two to three strongly reduced activities could be discerned from the testes of estrogen-treated subjects. The specific activity of each enzyme after fractionation was compared between control and regressed testes. No difference was observed in the activities of enzyme I. Enzyme II was markedly reduced in the regressed testes, but was clearly present. Enzymes III and IV were either totally absent or showed a marked reduction in the regressed testes. It is suggested that a correlation exists between the destruction of germ cells, as a consequence of estrogen treatment, and the marked reduction in the activity of enzymes III and IV.

Acid Phosphatase↗
PubMedDate not supplied

Further studies on human testicular acid phosphatases.

Four acid phosphatases were separated by gel filtration on Sepharose 6B and subsequent chromatography on DE-52 cellulose from human homogenate. The enzymes differed from each other in substrate preference, Km-values, modifier characteristics and molecular weights. The evidence obtained confirms that also in the human testis acid phosphatases of multiple molecular forms are present. Some of these may be specific for the testicular tissue.

Acid Phosphatase↗