The concentration of high-density lipoprotein (HDL) cholesterol in patients with severe obesity is generally subnormal. The exact mechanism linking obesity with reduced levels of HDL cholesterol remains unclear. In this study we evaluated the postheparin plasma lipolytic enzymes lipoprotein lipase (LPL) and hepatic lipase (HL) in a group of 24 obese women compared with controls and analyzed the interrelationships between insulin, postheparin lipolytic enzymes and HDL subfractions. Total HDL cholesterol was significantly lower in the obese subjects than in the controls, and the difference was mainly due to HDL₂ cholesterol concentrations. Mean fasting glucose, insulin and the summated means of glucose (Σ glucose) after the oral glucose tolerance test (OGTT) were not significantly different in the two groups. The summated means of insulin (Σ IRI) after the OGTT were significantly higher in the obese women than in the controls. LPL, HL and the HL-to-LPL ratio were significantly higher in the obese women than in the controls. HL and LPL correlated positively with Σ glucose, Σ IRI and body mass index (BMI) and negatively with plasma triglycerides. Partial correlation analysis demonstrated that, when exposed to similar Σ IRI values, HL and LPL were no longer correlated with Σ glucose, plasma triglycerides and BMI. HDL₂ cholesterol levels were negatively correlated with HL, posthepatic plasma lipolytic activity, Σ glucose, plasma triglycerides and BMI. HDL₂ cholesterol concentrations were directly correlated with LPL. Partial correlation analysis showed that when exposed to similar HL and LPL values, HDL₂ cholesterol values were no longer correlated with Σ glucose, Σ IRI, plasma triglycerides and BMI. Therefore, our results demonstrate that the low HDL₂ cholesterol levels found in obese women may be related to the high levels of HL and to the high HL-to-LPL ratio which in turn could be determined by the peripheral insulin resistance.

A family with nine siblings in which three siblings have been shown to have dexamethasone-suppressible hyperaldosteronism was studied. All three showed no significant changes of plasma aldosterone during angiotensin II infusion at incremental rates under baseline conditions. After dexamethasone administration (2 mg/d for 4 weeks) plasma renin activity (PRA) rose to normal-supranormal range, while plasma and urinary aldosterone were maintained at low-normal levels. No restoration of aldosterone response to angiotensin II was observed on dexamethasone. Two other siblings were found to be hypertensive with normal baseline data; however, both showed plasma aldosterone hyperresponsiveness to ACTH. In the four normotensive siblings aldosterone response to ACTH was normal. The family pedigree was consistent with autosomal dominant transmission of the disorder. HLA typing showed haplotype A3 Bw35 in all five hypertensive sibs and in one normotensive. In conclusion, low aldosterone compared to PRA, and plasma aldosterone unresponsiveness to angiotensin II infusion before and during dexamethasone, show functional impairment, at least temporary, of the zona glomerulosa. These findings support the hypothesis that aldosterone may be derived from the zona fasciculata in this disorder.

Clinical, radiological and scintigraphic studies and HLA type assessment were performed in 38 subjects, constituting all the first-degree members of three generations of the families of six patients affected with ankylosing spondylitis (AS). The families included both parents, all siblings and all children of the probands. Definite AS was found in three men and possible AS in another. In another man and in a woman, a diagnosis of asymptomatic bilateral sacroiliitis was made. These six subjects indicate a family prevalence of AS reaching 15.8%. HLA B27 was present in 20 individuals (52.6%), including those with definite and possible AS and the case with asymptomatic sacroiliitis. The woman with asymptomatic sacroiliitis lacked HLA B27 antigen. Our study confirms the familial occurrence of AS, but it shows the occurrence to be lower than that previously reported.

1. In previous studies, baseline and ACTH-stimulated hormone levels, plus HLA genotyping, have been used to detect heterozygous carriers in congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency (21-OHDS). 2. In the present study similar parameters were determined in a family of four including two children with CAH due to 11 beta-hydroxylase deficiency (11-OHDS), and a family of twelve including three sibs (two females, one genotypically male) with CAH due to 17 alpha-hydroxylase deficiency (17-OHDS). 3. HLA typing showed affected sibs with 11-OHDS to differ in one of their haplotypes. No significant differences in basal and ACTH-stimulated steroid levels were seen between the parents (obligate heterozygotes) and the general population. 4. In 17-OHDS, affected members differed from one another in one to two haplotypes; one patient had identical HLA profiles with two of the normal siblings, as did the genotypically male patient with two others; each of the other healthy siblings had one haplotype found in two of the affected subjects. The genes responsible for 11-OHDS and 17-OHDS--in contrast with 21-OHDS--do not appear to be HLA-linked. However, the measurement of ACTH-stimulated corticosterone levels may be useful, since the gene responsible for 17-OHDS seems to be expressed hormonally in the heterozygous state.

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