ABSTRACT
Three components of the male yellowfin Baikal sculpin pheromonal signal have been isolated from urine by diethyl ether extraction, thinayer chromatography (TLC), and high-performance liquid chromatography (HPLC). Using mass spectrometry, we have identified two of them as testosterone (T) and 11ß-hydroxytestosterone (11HT). These steroids are synthesized in testes during full spermatogenesis, and they are excreted in male urine with milt. The third component is not a steroid. It is more likely to be a polyene alcohol (farnesol). 2Z,6E-Farnesol possesses behavioral activity.
ABSTRACT
Proteoliposomes containing adenylate cyclase (AC) from rabbit heart ventricles were obtained using a novel reconstitution procedure from solubilized state. The enzyme preparation can be stimulated by 5'guanylylimidodiphosphate (GppNHp) and NaF, but not by isoproterenol. Hormonal responsiveness of AC is restored by either isoproterenol trapped by the proteoliposomes during the reconstitution or pretreatment of proteoliposomes with alamethicin. GTP in the presence of alamethicin decreases the affinity of beta-adrenoceptors to the agonist, thus confirming that the properties of reconstituted AC system do not differ from the native one. It is demonstrated that the degree of AC activation by isoproterenol depends strongly on the beta-adrenoceptors content in the proteoliposomes, which in turn can be changed artificially in the process of reconstitution. The described reconstitution technique might be a useful tool for investigating the role of component stoichiometry in the functioning of hormone-regulated AC-system.
Subject(s)
Adenylyl Cyclases/isolation & purification , Alamethicin/pharmacology , Anti-Bacterial Agents/pharmacology , Isoproterenol/pharmacology , Myocardium/enzymology , Receptors, Adrenergic, beta/metabolism , Adenylyl Cyclases/metabolism , Animals , Guanylyl Imidodiphosphate/pharmacology , In Vitro Techniques , Iodocyanopindolol , Liposomes/metabolism , Pindolol/analogs & derivatives , Pindolol/metabolism , Rabbits , Receptors, Adrenergic, beta/drug effectsABSTRACT
Using a Ca2+-selective electrode and the chlorotetracycline fluorescence technique, the effects of heparin on Ca2+ transport in the sarcoplasmic reticulum (SR) of skeletal muscles in the absence of oxalate were investigated. It was shown that heparin (0.5-10 micrograms/ml) causes a rapid release of 40-50 nmol Ca2+/mg protein from the terminal cistern SR vesicles bound to 130-150 nmol/mg protein of Ca2+ in the presence of ATP. However, heparin has practically no effect on the longitudinal cistern fraction of SR. The effects of heparin can be prevented by ruthenium red. No influence of heparin is observed in the case of the Ca2+-induced release of Ca2+ from the terminal cisterns. When the Ca2+ release is induced by heparin, no Ca2+-induced release of Ca2+ takes place.
