Inhibin B in men with severe obesity and after weight reduction following gastroplasty.

Although the effect of obesity on some gonadal functions in men is known, its effect on Sertoli cell function has not been reported. We tested the hypothesis that the serum inhibin B level is decreased in men with severe obesity, and that this change persists after significant weight loss. We measured gonadal hormones in 17 obese men before (baseline) and after weight reduction following silastic ring vertical gastroplasty (SRVG).

Analysis of the peroxisome proliferator activated receptor gamma (PPARgamma) gene in HAIRAN syndrome with obesity.

Objectives: To test the hypothesis that the triad of hyperandrogenism, insulin resistance and acanthosis nigricans (HAIRAN syndrome) in the presence of obesity, also known as type C insulin resistance, is caused by mutations in the gene for peroxisome proliferator activated receptor gamma (PPARgamma), a receptor for the thiazolidinedione drugs that enhance sensitivity to insulin. To investigate possible correlations between mutations in PPARgamma and the degree of insulin resistance.

Design: A candidate gene approach to study the molecular basis for a syndrome of obesity; a comparison of genotype with in vivo phenotype.

Analysis of the insulin receptor gene tyrosine kinase domain in obese patients with hyperandrogenism, insulin resistance and acanthosis nigricans (type C insulin resistance).

Objective: To test the hypothesis that the triad of hyperandrogenism, insulin resistance and acanthosis nigricans (HAIR-AN syndrome) in the presence of obesity, also known as type C insulin resistance (type C), is caused by mutations at the tyrosine kinase domain of the insulin receptor gene.

Design: A candidate gene approach to study the molecular basis for a syndrome of obesity.

Subjects: 15 patients with type C insulin resistance and 25 control individuals.

Expression and purification of functional human 17 alpha-hydroxylase/17,20-lyase (P450c17) in Escherichia coli. Use of this system for study of a novel form of combined 17 alpha-hydroxylase/17,20-lyase deficiency.

Enzymatically active human 17 alpha-hydroxylase cytochrome P450 (P450c17) has been expressed in and purified from Escherichia coli. The cDNA containing modifications within the amino-terminal eight codons which are favorable for expression in E. coli, as well as codons for 4 histidine residues at the carboxyl terminus, was placed in the pCWori+ expression vector.