Adenylate cyclase in mouse testis

Cytochemical study on the distribution of adenylate cyclase in guinea pig testis

The distribution of adenylate cyclase in testis, by means of a specific substrate adenylyl-imidodiphosphate (AMP-PNP), has been determined. Membrane-associated reaction products, indicative of adenylate cyclase activity, are localized by a complete cytochemical medium (containing 10 mM NaF) at the level of the basal compartment of the seminiferous epithelium, on the basal surface of Sertoli cells, and on adjacent plasma membranes of Sertoli cells and spermatogonial cells. At the level of the adluminal compartment, reaction products were found on adjacent plasma membranes of Sertoli cells and early or elongated spermatids. Adenylate cyclase reaction products are detectable by a basal incubation medium (without 10 mM NaF) only in the adluminal compartment on the spermatid plasma membranes.

Theophylline-estrogen interaction in the rat uterus: role of the ovary

Uterine edema induced by 0.1 microgram/100 g body wt of estradiol further increases in the presence of theophylline. Theophylline alone or in the presence of 0.001, 0.01, 0.1, and 1 microgram/100 g body wt of estradiol increases uterine RNA and protein content 6 h after its administration, as compared with the same doses of estradiol alone. Both phenomena disappear in the ovariectomized immature rat, suggesting that theophylline potentiates the action of gonadotropins, increasing the synthesis of endogenous ovarian estrogens by the immature ovary. Theophylline decreases the number of eosinophils in the blood and concurrently decreases estrogen-induced uterine eosinophilia at doses of 0.01, 0.1, 1, 10, and 30 micrograms/100 g body wt of estradiol. Estrogen binding by uterine eosinophils in vitro increases in the presence of theophylline. This effect of theophylline could also explain the increase in vivo in estrogen-induced uterine edema.

Purification and kinetic properties of the soluble Mn2+-dependent adenylyl cyclase of the rat testis

The soluble Mn2+-dependent adenylyl cyclase (AC) of the rat testis was purified 1500-fold with some 19% yield of the initial activity. These results were accomplished by conventional separation techniques including (NH4)2SO4 precipitation of testis cytosol (106 000 x g), gel filtration (Sephadex G-200) and ion-exchange chromatography (Sephadex DEAE-A50) followed by Sephadex G-100 gel filtration and isoelectric focusing. Analysis by polyacrylamide-gel electrophoresis (PAGE) of aliquots from each purification step revealed the following. (a) The Mn2+-dependent AC migrated with a Rf value of 0.40 irrespective of the degree of purification. (2) The AC peak from the isoelectric focusing column separated into 2 major protein bands; however, only one band (Rf 0.40) had AC activity. The molecular weight emerging from the position of migration on the Sephadex G-200 and G-100 columns appeared to be consistent at 47 000-48 000 D, as estimated from the relationship log MW versus elution volume. The purified enzyme fulfilled the requirements for a simple Michaelis-Menten kinetics with an apparent Km for Mn2+ and MnATP2- of 6.7 and 2.5 mM, respectively. Varying the concentrations of ATP or Mn2+ separately did not alter the apparent affinity (Kmapp) for the other parameter. These and previous data from our laboratory show that the physico-chemical and kinetic properties (molecular weight and Kmapp for Mn2+ and MnATP2-) do not alter during purification. Furthermore, the additional step of affinity chromatography seems obligatory if a homogeneous AC preparation is to be obtained.