Extremely high levels of corticosteroids and low levels of corticosteroid binding macromolecule in plasma of marmoset monkeys.

Marmoset monkeys were shown to have extremely high resting plasma corticosteroid levels compared to those of macaque monkeys and humans. A major component of corticosteroids seems to be cortisol. Levels of total 11-deoxy-17-KS in plasma of marmoset monkeys were very low (less than 0.

A radioreceptor assay for insulin: direct measurement of dog pancreatic vein serum insulin.

A simple radioreceptor assay for insulin rat liver membranes as receptor sites, with sufficient specificity precision, and sensitivity to detect 10 ng or 276 muU/ml of serum insulin, has been developed. In the presence of standard porcine insulin at the concentration of 1.0 ng/tube, approximately 8% of 125I-porcine insulin was bound to the plasma membranes and ninety-five per cent of this binding was inhibited by 1.

Radioimmunoassay for etiocholanolone.

A sensitive and reliable radioimmunoassay for serum unconjugated etiocholanolone (3alpha-hydroxy-5beta-androstan-17-one) is reported. The antiserum was obtained from rabbits by immunization of etiocholanolone-17-(O-carboxymethyl) oxime [CMO]-bovine serum albumin [BSA]. Two ml of serum with 3H-etiocholanolone added for recovery was extracted with ether, and etiocholanolone was separated from cross-reacting steroids by Sephadex LH-20 column chromatography.

Frozen preservation of human malignant tumors transplanted into nude mice.

Five transplantable tumors, which originated from human maligant neoplasms and had been maintained in nude mice, were frozen at--70 degrees preserved for 1226 days. Tumor tissue was minced in a mixture of tissue culture medium, 10% dimethyl sulfoxide, and 10% calf serum before freezing. The transplantability of frozen tumors was examined after thawing.

Ascites form of a human cancer serially transplantable in nude mice.

Human adenocarcinoma cells injected into the peritoneal cavities of BALB/c nude mice (nu/nu) induced ascites carcinoma. The inoculant was obtained from subcutaneous tumors produced in nude mice by an injection of ascites cells from a patient with carcinomatous peritonitis caused by mucinous adenocarcinoma of the stomach. An ascitic fluid began to accumulate 45 days after inoculation and reached the maximum volume within 120 days.

Enzymatic radioiodination of succinyl cyclic AMP tyrosine methyl ester by lactoperoxidase and radioimmunoassay for cyclic AMP.

A highly specific and simple radioimmunoassay for cyclic AMP with a sensitivity of 0.04 picomoles/tube has been developed according to the method of Steiner et al., using 125I-succinyl cyclic AMP tyrosine methyl ester as a tracer.

Human gastric choriocarcinoma serially transplanted in nude mice.

A gastric choriocarcinoma cell line capable of producing human chorionic gonadotropin (HCG) was studied by sc transplantation and serial passages into nude mice fed under specific pathogen-free (SPF) conditions. The tumor-take rate at the serial heterotransplantation in SPF mice was high (greater than 95%), in contrast with a low rate in coventional animals (35%). The restoration of morphology and function of the original neoplasm were exclusively verified in SPF mice.

Radioreceptor assay for insulin.

A sensitive and simple radioreceptor assay (RRA) capable of detecting 10 muU/ml of serum insulin has been developed using the crude membrane fraction of guinea pig kidney and 125I-porcine insulin. Using this assay system, serum insulin during 100 g oral glucose tolerance tests in six males including one obese man was measured. The mean concentration of serum insulin increased from 19 muU/ml during fasting to maximum of 90 muU/ml after 60 min of glucose load and then gradually declined to 38 muU/ml by 180 min.

The effect of ACTH administration on serum estrogens, LH, and FSH in the aged.

The effect of administration of long acting ACTH on serum levels of estrogens, LH and FSH was studied in aged subjects. Nine women and 5 men between 66 and 90 years of age were examined. One milligram of long-acting synthetic ACTH was given in every 12 h for 2 days.