Margaret W. Couch

Isomeric octopamines: their occurrence and functions

p-Octopamine is a widely distributed invertebrate neurotransmitter (Evans 1978). It also occurs in the mammalian sympathetic nervous system, where its function is unknown (Axelrod & Saavedra 1977). Recent advances (Ibrahim et al 1984, 1985) in mass spectrometric analytical techniques have disclosed that, in addition to p-octopamine, 0and m-octopamine and the N-methyloctopamines (mand p-synephrine) also occur naturally in mammals. Evidence indicates that mand p-octopamine are located in sympathetic nerves with noradrenaline whereas mand p-synephrine are found only in adrenal gland (Ibrahim et al 1985). The location of o-octopamine is unknown but it is probably not in the same anatomical structure as mand p-octopamine and noradrenaline (Ibrahim & Williams 1985). This review summarizes the present knowledge concerning the distribution and possible functions of the three positionally isomeric octopamines.

Identification of ortho-octapamine and meta-octopamine in mammalian adrenal and salivary gland

Abstract Ortho - and meta - octopamine have been identified in beef and rat adrenal gland and in rat salivary gland by means of gas chromatography-mass spectrometry. The tritrifluoroacetyl derivatives of ortho -, meta - and para - octopamine were resolved by gas chromatography and shown to produce two characteristic ions at m/e 315 and m/e 328. The di-O-trimethylsilyl-N-trifluoroacetyl derivatives of these three isomers were also resolved by gas chromatography and shown to produce a characteristic ion at m/e 267. Biological samples were homogenized in formic acid:acetone, subjected to ion-exchange chromatography and then derivatized. When the derivatized biological extracts were examined for each characteristic ion, peaks were observed at the exact retention times of the standards. The three isomers are present in adrenal gland in concentrations of ∼1 μg g−1 and in rat salivary gland in concentrations of ∼0.1 μg g−1. This evidence confirms a previous report of the presence of m -octopamine in rat salivary gland measured by a radiochemical enzyme assay and is the first report of the presence of o -octopamine in biological tissue.

Natural Occurrence and Metabolism of the Isomeric Octopamines and Synephrines

The development of a radiochemical enzyme assay for the quantitative determination of p-octopamine (Molinoff et al, 1969) led to its discovery in a wide variety of invertebrate nerve systems and in mammalian sympathetic nerves. Subsequent work led to the conclusion that p-octopamine is an invertebrate neurotransmitter and a cotransmitter with norepinephrine in mammalian sympathetic nerves (Axelrod and Saavedra, 1977). It was discovered in 1976 that the radiochemical enzyme assay was not specific for p-octopamine because the m- and p- isomers of octopamine could not be resolved. The use of a modification of the technique showed that both m- and p-octopamine are present in rat salivary gland (Robertson et al, 1977) and brain (Danielson et al, 1977). The radiochemical enzyme assay depends upon norepinephrine N-methyltransf erase, which can accept all three positional isomers of octopamines as substrates with varying efficiency. The resultant products, the corresponding synephrines, are also substrates for the enzyme (Axelrod, 1962; Fuller et al, 1981). Consequently any one of these amines (or a mixture of them) would have been detected by the original unmodified assay but identified and quantified as p-octopamine.

New method for the synthesis of radioactive 19-iodocholest-5-en-3β-ol

Abstract In 1970, 131I-19-iodocholest-5-en-3β-ol (VIII-131I) was synthesized and shown to concentrate in the adrenal cortex of dogs by Counsell et al . [1]. Beierwaltes and his colleagues at the university of Michigan have shown this radiopharmaceutical to be an effective adrenocortical scanning agent for the diagnosis of 5 types of adrenal disease in humans [2]. Radioactive 19-iodocholesterol is not available from commercial sources although it may be purchased from the University of Michigan Nuclear Pharmacy, Ann Arbor, as a radiochemical and converted to a radiopharmaceutical [3]. For this reason we undertook to synthesize it de novo as described by Counsell et al . [1]. We found that 19-iodocholesterol prepared by this route contained an impurity, the amount of which varied from 20% to 60% as estimated by 13C nuclear magnetic resonance spectroscopy (CMR). We now describe a modification of this synthesis to yield VIII-131I of greater than 98% chemical purity.

Synthesis and purification of radioactive 6β-iodomethyl-19-norcholest-5(10)-EN-33-ol

Abstract A method for the synthesis and purification of 6β-iodo-methyl-19-norcholest-5(10)-ene-3β-ol- 131 I of >98 mole% chemical purity and >99% radiochemical purity is presented. Carbon-13 and proton NMR were used to establish the identity and purity. Discrepancies in the characterization of this compound, previously published by two other research groups, are discussed.

Increased excretion of m-hydroxyphenylglycol and m-hydroxymandelic acid in neuroblastoma

Abstract The urine of three out of four patients with neuroblastoma was found to have a 14-fold elevation of m -hydroxyphenylglycol and a 6-fold elevation of m -hydroxymandelic acid. This was attributed to an increased formation of m -octopamine and m -synephrine by the tumor.

Normal excretion of m-hydroxymandelic acid in hypertensive patients

o-Hydroxymandelic acid (OHMA), m-hydroxymandelic acid (MHMA) and p-hydroxymandelic acid (PHMA) were measured in the urine of 42 normotensive and 54 hypertensive patients. Patients having high urinary MHMA levels were all found to be ingesting medications containing m-synephrine (phenylephrine). These patients also had high levels of urinary m-synephrine which was excreted as the glucuronide. When patients ingesting m-synephrine were excluded from the analysis, no significant differences were observed between the two groups for the urinary excretion of OHMA, MHMA and PHMA.

Increased urinary excretion of m-octopamine in neuroblastoma

The urine of three patients with neuroblastoma was found to have a 3 to 5-fold elevation of m-octopamine concentration. The concentration of m-synephrine was normal in two cases and slightly elevated in the third. These findings were attributed to an increased formation of m-octopamine by this tumor.

Identification and quantitative determination of saccharin in biological fluids

Abstract A gas chromatographic method for the qualitative and quantitative determination of urinary and plasma saccharin as its N-methyl derivative has been described. The structure of this derivative was proved by mass spectrometry and by proton and 13C NMR. About 96% of the saccharin was excreted unchanged in the first 24 hr urine collection after oral intake of saccharin by man. This method is relatively simple and rapid and may be adapted for other biological fluids.

Carbonless copy paper: a review of its chemical components and health hazards.

The components of carbonless copy paper (CCP) and the chemistry involved in its manufacture are reviewed. Claims that the routine use of CCP can cause health problems ranging from skin, eye, and lung irritation to severe headaches and neurological damage are described; yet no definitive studies have been conducted that show correlation between CCP use and these symptoms. The toxicological properties of CCP components, many of them precursors to the dye-containing microcapsules or dye solvents that may be causing these problems, are discussed. Recommendations for the minimization of possible physiological reactions to CCP include reduction of usage time; use of the CCP in a well-ventilated area; storing large quantities of CCP, both new or archived, away from work area; and the practice good hand hygiene.