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Testes of mature chum salmon (Oncorhynchus keta Walbaum) were examined histologically for interstitial cells and extracts of testes assayed biologically for the presence of androgens. The histological examination showed numerous interstitial cells similar to those described in some other fish and in mammals. The bioassay established the presence of androgenic substance (probably testosterone). The amount present in salmon testes was calculated to be roughly equivalent to the amount present in mammalian testes.

The experiments reported here were carried out to study the in vitro binding of 131 I to bovine milk protein and the factors influencing this binding. Incubation of inorganic carrier-free 131 I-iodide with fresh raw milk at 37C for two hours showed as much as 50% of the 131 I bound to milk protein, and that as much as 80–90% could be bound in 12–24 hours. It was also shown that this reaction is both time- and temperature-dependent and could be readily blocked by incubation at 8C, boiling the milk prior to incubation, addition of carrier iodide or antithyroid agents such as Tapazole (methyl mercaptan imidazole). Paper chromatography of enzymatic digests of the milk showed the protein-bound 131 I in milk is present as 131 I-labeled monoiodotyrosine. No other 131 I-labeled compounds were observed. These studies would tend to indicate that the binding of 131 I-iodide to milk protein involves an enzymatic oxidation of the iodide.

SummaryA spectrophotofluorometric method for determination of plasma salicylates is described in which a dextrangel (Sephadex) filtration system is used instead of solvent extraction or protein precipitation for separation of non-protein-bound salicylate from plasma protein. This method permits rapid estimation of binding of drug to protein in addition to estimation of free, acetyl and total salicylate. At physiological pH very little salicylate is bound to the protein in dog plasma (