No abstract

Twenty males participated in a 2-month study examining the relationship between 8 a.m. plasma testosterone levels and orgasmic frequency. Within subjects, higher levels of testosterone are associated with periods of sexual activity. Over subjects, however, the direction of the relationship is reversed. Mean testosterone levels were higher for sexually less active individuals.

Alpha‐methyl‐para‐tyrosine (AMPT), an inhibitor of catecholamine biosynthesis, was given to 7 manic and 3 depressed patients under double‐blind conditions. Five of the 7 manic patients became less manic, while the three depressed patients became more depressed. Urinary excretion of catecholamine metabolites and dopamine was significantly decreased in all. These behavioral and biochemical changes confirm previous indirect evidence implicating catecholamines in affective disorders.

Plasma DOPA leveLy were determined in depressed patients at various times after oral administration of levodopa with and without a peripheral decarboxylase inhibitor, D,L-alphamethyl-dopa-hydrazine (MK-485). Pretreatment with MK-485 caused an approximately tenfold increase in the peak plasma leveLY following a DOPA load. Equivalent plasma levels were achieved with ~o the dose of levodopa with use of MK-485. A significant prolongation of the half-life of the amino acid in the plasma was aLYo achieved. The increase of plasma DOPA leveLY with MK-485 is in the same range as the potentiation of clinical effect with this inhibitor.