The effect of prolactin on the secretory activity of the nasal salt-gland of the domestic duck (Anas platyrhynchos)

When injected intravenously, 20 i.u. ovine prolactin significantly enhanced the output of fluid from the minimally stimulated nasal salt-gland of ducks within 5 min. This effect persisted for a further 5 min. In ducks which were still producing nasal fluid 25 min. after prolactin administration, a second enhancement of secretion was observed which could be related to an indirect effect induced by a rise in the blood glucose concentration. The initial, rapid enhancement of secretion could not be attributed to changes in blood composition and it seems possible that prolactin may have a direct effect on the avian salt-gland.

Direction of chain growth in polysaccharide synthesis

The biosynthesis of a bacterial polysaccharide-the surface O-antigen of Salmonella newington-differs in several respects from the more classical example of glycogen synthesis. Sugars are not transferred directly to the antigen from sugar nucleotide precursors but are transferred first into lipid-linked oligosaccharides. Growth of the polysaccharide chain then occurs by assembly of these lipid-linked precursors at the reducing end of the polymer rather than at its nonreducing end as in glycogen. This method of assembly, in which nascent chains are transferred to the next subunit, is analogous to the growth of proteins or fatty acids. It seems possible that these differences reflect the more complex requirements of a surface polysaccharide synthesized by membrane-bound enzymes. If this is the case, then several other polysaccharide systems may be synthesized by comparable mechanisms.

The effect of adenohypophysectomy on the extrarenal and renal excretion of the saline-loaded duck(Anas platyrhynchos)

Domestic ducks were adenohypophysectomized and 2–3 weeks later were loaded with hypertonic saline. Normal intact ducks and sham-operated ducks were similarly treated. For 2 hr. nasal gland secretion was almost completely inhibited (0·20 g.) in the adenohypophysectomized ducks and was significantly reduced (4·93 g.) in the sham-operated ducks compared with the normal intact controls (14·74 g.).

When the renal response of the adenohypophysectomized ducks was compared with that of the normal intact controls no significant difference was found as far as volume of urine and concentration of Na+ and K+ were concerned. When compared with sham-operated controls, however, these values were significantly lower in adenohypophysectomized ducks.

The adrenal weight was not significantly reduced in the adenohypophysectomized ducks, but the weights of thyroid, nasal gland and testis decreased significantly. Histological examination of the adrenal glands of the adenohypophysectomized ducks showed that the central regions were atrophic while the peripheral regions remained normal. Nasal glands, thyroid glands and testes were also examined.

It is concluded that the adenohypophysis plays a major part in regulating extrarenal excretion.

Enzyme strip method of blood glucose determination

Determinations of blood glucose levels by an enzyme strip test and the AutoAnalyzer were compared in 542 samples. The enzyme strip test tended to overestimate glucose values in the lower ranges and underestimate them in the upper ranges. Although agreement between the methods was reasonably good in the 60 to 130, and 130 to 200 mg. per 100 ml. ranges, underestimation of values by the strip test occurred in 10 per cent of the samples at the latter range. A study of the sources of variability of the enzyme strip test revealed that the color-matching step was most likely the source of most of the technical error. The latter was high for the test, the coefficient of variation of blind independent determinations on ten samples by four technicians being 27.5 per cent. The clinical usefulness of the test is limited, and it should not be employed if other methods of determining glucose levels are easily available.

BILE AND BLOOD PLASMA CHOLESTEROL AS INFLUENCED BY BLOOD DESTRUCTION IN NORMAL AND BILE FISTULA DOGS

Destruction of large amounts of red cells in normal and bile fistula dogs by means of acetyl phenylhydrazine causes no significant alterations of the blood plasma but there is some decrease in the bile cholesterol. During Bartonella canis infection the splenectomized bile fistula dog periodically breaks down large quantities of red cells with slight decrease in the plasma cholesterol and marked decrease in the bile cholesterol. In the periods of blood regeneration following such acute anemias there are no significant alterations in the values for plasma or bile cholesterol.