background: nicotine, cotinine and cadmium are harmful components of cigarettes that have an effect on human reproductive function. although the effects of cigarette smoke on male reproductive function is characterized in several articles its mechanism of action is still unknown. in the present study, we investigate the effect of nicotine, cotinine and cadmium on human sperm creatine kinase act...

This study investigated the effects of hypoxia (experiment 1) and the effects of hypoxia following short-term training (experiment 2) on metabolism in working muscle. In experiment 1, eight males with a peak aerobic power (VO2peak) of 45 +/- 1.7 ml x kg(-1) x min(-1) (x +/- SE) cycled for 15 min at 66.1 +/- 2.1% VO2peak while breathing room air [normoxia (N)] or 14% O(2) [hypoxia (H)]. In exper...

Creatine Kinase and the Correlates of Blood Pressure in a Random Population Sample To the Editor: We hypothesized that creatine kinase (CK), the central regulatory enzyme of energy metabolism, amplifies blood pressure responses, and subsequently showed that CK activity is independently associated with blood pressure.1 CK catalyzes the reversible transfer of the high-energy phosphate moiety (P) ...

Methyl phosphate has been studied as a possible donor of methyl groupings for the formation of creatine by homogenates of liver tissue of rats and as a substitute for choline in the growth of rats receiving homocystine as the source of sulfur in their diet. It was found that methyl phosphate was an apparent source of methyl groupings in the in vitro synthesis of creatine but could not be substi...

Methyl phosphate has been studied as a possible donor of methyl groupings for the formation of creatine by homogenates of liver tissue of rats and as a substitute for choline in the growth of rats receiving homocystine as the source of sulfur in their diet. It was found that methyl phosphate was an apparent source of methyl groupings in the in vitro synthesis of creatine but could not be substi...

We demonstrate that human placenta is a convenient source of creatine kinase isoenzyme BB. We compare the physicochemical and catalytic properties with those of other creatine kinase isoenzymes: purified human abdominal muscle MM and brain BB. We also describe a stabilizing medium for creatine kinase BB. Human placental and brain BB have similar catalytic properties, the respective Km values fo...

The iodoacetate-nitrogen-poisoned muscle offers the possibility of studying the stoichiometry of the single muscle twitch since metabolic resynthesis by glycolysis and oxidative phosphorylation are blocked, and there remains as an energy source only the creatine phosphoryltransfer system, creatine phosphate reacting with adenosinediphosphate to give the triphosphate and creatine. It is shown, p...