Plasma testosterone during nocturnal sleep in normal men

Plasma testosterone was measured by a competitive protein binding procedure at 10 to 20 minute intervals in five normal adult men during two nights of sleep. Blood samples were obtained by means of an indwelling venous catheter while sleep was monitored polygraphically. There were 1–4 abrupt elevations of plasma testosterone concentration per night in each of the subjects with an average increase of 244 ng/100 ml ± 45.5 (SE) or 59% above the values present at the onset of the episode. The fluctuations in plasma testosterone were superimposed on a nocturnal rise of the hormone observed in seven of the nights. The average of all samples taken during each hour period through the ten nights revealed a highly significant (P<0.001) nocturnal increase in plasma testosterone. The findings did not support the existence of a relation between REM sleep and an increase in testosterone levels.     

Phenethylamines in brain and liver of rats with experimentally induced phenylketonuria-like characteristics

1. Phenethylamines were extracted from brain and liver of rats with phenylketonuria-like characteristics produced in vivo by inhibition of phenylalanine hydroxylase (EC 1.14.3.1) with p-chlorophenylalanine, with or without phenylalanine administration. To protect amines against oxidation by monoamine oxidase, pargyline was also administered. 2. beta-Phenethylamine was the major compound found in brain and liver. beta-Phenethanolamine and octopamine were also present, in lesser amounts, and the concentrations of these three amines paralleled blood phenylalanine concentrations. By comparison, tissues from control animals had only very low concentrations of these amines. 3. Small amounts of normetadrenaline, m-tyramine and 3-methoxytyramine were also found. 4. The inhibitors used, p-chlorophenylalanine and pargyline, gave rise to p-chlorophenethylamine and benzylamine respectively, the first via decarboxylation, the second probably by breakdown during extraction. 5. Distribution of phenethylamines in different brain regions and in subcellular fractions of rat brain cells was also investigated. The content of phenethylamine was highest in the striatum. 6. These findings are discussed in the light of changes occurring in human patients with uncontrolled phenylketonuria.     

Altered Mitochondrial Respiration in a Chromosomal Mutant of Neurospora crassa

A mutant of Neurospora crassa (cni-1) has been isolated that has two pathways of mitochondrial respiration. One pathway is sensitive to cyanide and antimycin A, the other is sensitive only to salicyl hydroxamic acid. Respiration can proceed through either pathway and both pathways together in this mutant account for greater than 90% of all mitochondrial respiration. The cni-1 mutation segregates as a nuclear gene in crosses to other strains of Neurospora. Absorption spectra of isolated mitochondria from cni-1 show typical b- and c-type cytochromes but the absorption peaks corresponding to cytochrome aa(3) are not detectable. Extraction of soluble cytochrome c-546 from these mitochondria followed by reduction with ascorbate reveals a new absorption peak at 426 nm that is not present in wild-type mitochondria. This peak may be due to an altered cytochrome oxidase with abnormal spectral properties. Mitochondria from cni-1 have elevated levels of succinate-cytochrome c reductase but reduced levels of nicotinamide adenine dinucleotide reduced form cytochrome c reductase and of cyanide- and azide-sensitive cytochrome c oxidase. These studies suggest that the cni-1 mutation results in the abnormal assembly of cytochrome c oxidase so that the typical cytochrome aa(3) spectrum is lost and the enzyme activity is reduced. As a consequence of this alteration, a cyanide-insensitive respiratory pathway is elaborated by these mitochondria which may serve to stimulate adenosine 5'-triphosphate production via substrate level phosphorylation by glycolysis and the Krebs cycle.