Captopril (SQ 14225) depresses drinking and aldosterone in rats lacking vasopressin.

Angiotensin II is dipsogenic, and vasopressin (ADH) regulates renal water excretion. Together, these hormones govern overall mammalian water balance. The Brattleboro rat with inherited diabetes insipidus (DI) lacks ADH and is therefore a convenient model with which to elucidate mechanisms regulating water metabolism. In the present studies, angiotensin II has also been removed from DI rats by the administration of an inhibitor (captopril, SQ 14225; D-2-methyl-3-mercaptopropanoyl-L-proline) of the enzyme which converts angiotensin I, the relatively inert component of the renin-angiotensin system, to angiotensin II, the biologically active substance. SQ 14225 reduced the drinking rates, and after 6 days lowered peripheral plasma aldosterone concentrations were associated with hyperkalaemia. We conclude that the polydipsia of diabetes insipidus partly results from elevated plasma renin activities and angiotensin II concentrations seen in this syndrome. Further, the apparent hypoaldosteronism of DI Brattleboro rats reflects differences in both tissue usage of the steroid and adrenocortical sensitivities associated with polyuria, hyperosmolarity and possibly potassium wasting.     

2'5' oligo(A) polymerase activity in serum of mice infected with EMC virus or treated with interferon

Interferon-treated cells show an increase in two double-stranded RNA (dsRNA)-dependent enzymatic activities involving an oligoadenylate polymerase and a protein kinase (ref. 1 and refs therein). The polymerase converts ATP into a series of oligonucleotides characterized by 2'5'-phosphodiester bonds, designated 2'5'-oligo(A) or 2-5A (ref. 1). These oligonucleotides activate an endoribonuclease that degrades RNA in extracts of control and interferon-treated cells. These observations have been made in tissue culture cells and no informatin is yet available on these enzymatic activities in animals with elevated interferon levels. We report here on 2-5A synthesis in tissue homogenates and serum of mice infected with encephalomyocarditis virus (EMCV); this virus induces interferon synthesis when injected intraperitoneally into mice. Significant synthesis of 2-5A was detected in extracts of spleen and lungs, but also, surprisingly, in the serum of these mice. Subsequent experiments showed synthesis of 2-5A in serum of mice treated with the interferon inducer poly(I) x poly(C) (ref. 3) or with mouse fibroblast interferon.     

A crystalline,toxic, peptide metabolite ofTrichoderma spp. isolated from soil

Summary Isolates ofTrichoderma spp. from pasture soils of Nova Scotia produce at least 7 toxic peptides, probably related to alamethicin, some of which inhibit the growth of cellulase producing rumen bacteria. One of the peptides has been obtained in crystalline form and crystal data on this material is reported.     

Lipid accumulation in mouse hepatocytes after morphine exposure

Summary After morphine injection lipid accumulation in mouse hepatocytes begins within 2 h and continues for 24 h when most hepatocytes are filled with lipid droplets. In spite of morphine maintenance the liver recovers as the accumulated lipids are coupled with protein and subsequently transported and released into the perisinusoidal space of Disse.Supported by USPHS Grants GM 15490, 5 SO7 RR05386-16 and DA-01310.     

The effects of stimulation of the olfactory bulbs on the serum proteins of the rat

Resumen La estimulación electroquímica bilateral de bulbos olfatorios con corriente directa de 1 mA durante 10 segundos en ratas, produce aumento de concentration de proteinas séricas totales, albúmina y globulina .