Kottke, Bruce A.

Total daily bile acid excretion was measured in 10 patients with primary hypercholesteremia and in nine patients with combined hypercholesteremia and hypertriglyceridemia by using 14 C-labeled cholic acid and 3 H-labeled chenodeoxycholic acid. The average bile acid excretion by the patients with primary hypercholesteremia was 282 mg/day; that by the patients with combined hypercholesteremia and hypertriglyceridemia, 1,094 mg/day. These findings suggest a fundamental difference in cholesterol metabolism in these two types of hyperlipidemia.

Data on 11 patients with orthostatic hypotension and primary systemic amyloidosis have been presented. Dizziness and light-headedness or syncope significantly hampered the involved patients. Three were incapacitated by orthostatic hypotension. Diarrhea, nausea, vomiting, and loss of weight were common, and adrenal insufficiency was seriously considered in the differential diagnosis of six of the 11 patients. Abnormal sweating was found in all six in whom this test was done. The drug 9-α-fluorohydrocortisone showed promise in symptomatic therapy of the condition. The possibility of primary systemic amyloidosis should be considered in the presence of orthostatic hypotension. Rectal biopsy and bone-marrow aspiration are recommended as initial biopsy procedures unless another organ suitable for biopsy is obviously involved.

OBJECTIVE Fasting hyperinsulinemia in the presence of normoglycemia usually indicates insulin resistance and is characteristic of populations at high risk for developing NIDDM. Hyperinsulinemia predicts the development of impaired glucose tolerance and NIDDM in Pima Indians, a population with a high incidence of NIDDM. Insulin concentrations in population-based samples of children who have different risks of developing NIDDM later in life have not been reported previously. RESEARCH DESIGN AND METHODS We compared fasting insulin concentrations in two populations of nondiabetic children, 6–19 yr of age: Pima Indians from southern Arizona and Caucasians from Minnesota. RESULTS Insulin concentration varied with age, sex, glucose concentration, and relative weight. Mean fasting insulin concentration was 140.3 pM in Pima Indian males, 94.4 pM in Caucasian males, 171.5 pM in Pima Indian females, and 107.1 pM in Caucasian females. For each sex, the mean fasting insulin concentration, controlled for age, glucose, and relative weight, was significantly higher in the Pima Indians than in the Caucasians (P < 0.001). CONCLUSIONS From a young age, Pima Indian children have higher fasting insulin concentrations than Caucasian children. As hyperinsulinemia predicts subsequent NIDDM, these data suggest that the susceptibility to NIDDM is manifest at a young age as fasting hyperinsulinemia.

AbstractLipid and apolipoprotein (apo) A‐I concentrations in different density fractions of New Zealand White (NZW) and Watanabe (WHHL) rabbit plasma were studied. Aside from the low plasma apoA‐I and high density lipoprotein (HDL) cholesterol levels in WHHL rabbits, the distribution of apoA‐I was also different between the two rabbits. ApoA‐I was concentrated in both the HDL2 and HDL3 fractions of NZW rabbits but was found primarily in the HDL3 fraction of WHHL rabbits. ApoA‐I secretion in these two rabbits was further studiedin vitro by using intestinal and hepatocyte cell cultures. ApoA‐I secretion was highest from cultures of the duodenum and the proximal end of the jejunum; whereas, cell cultures of the distal end of the small intestine secreted very little apoA‐I into the medium. Intestinal cell cultures from WHHL rabbits secreted less, but significant amounts of, apoA‐I compared to that of NZW rabbits. ApoA‐I was most concentrated in the density range of 1.12–1.21 (HDL3) fraction in medium containing 10% fetal calf serum (FCS). Serum‐free medium promoted apoA‐I secretion by intestinal cell cultures that was mostly found in the d>1.21 (lipoprotein‐deficient) fraction. Hepatocytes isolated from the same rabbits by collagenase perfusion secreted little apoA‐I, and it was found only in the d>1.21 fraction. The addition of oleic acid into the culture medium with 10% FCS decreased the secretion of total apoA‐I and HDL by intestinal cell cultures and increased the secretion of very low density lipoprotein (VLDL) and intermediate density lipoproteins (IDL). The results indicate that intestinal cells, not hepatocytes, are responsible for the secretion of apoA‐I and HDL3 in rabbits, and that the secretion may be regulated under different nutritional conditions.