A novel circulating hormone of testis origin in humans

Insulin-like factor 3 (INSL3) is a member of the relaxin-insulin family, and it is expressed in pre- and postnatal Leydig cells of the testis. This peptide affects testicular descent during embryonic development, and mutations in INSL3 gene or its receptor LGR8 (leucine-rich repeat-containing G protein-coupled receptor 8)/GREAT (G protein-coupled receptor affecting testicular descent) cause cryptorchidism in humans. The expression of LGR8/GREAT in different tissues and the production of INSL3 also by adult-type Leydig cells suggest additional roles of this hormonal system in adulthood. In this preliminary report we performed the first analysis in humans of INSL3 using a novel RIA kit to measure INSL3 concentrations in serum of normal men and with different testicular pathologies. The results show that INSL3 is circulating in adult men, and it is almost exclusively of testicular origin. Subjects with severe testicular damage, such as men with severe infertility, produce low amount of INSL3, and the concentrations of this hormone seem to reflect the functional status of the Leydig cells. In particular, INSL3 concentrations may be an even more sensitive marker of Leydig cell function than testosterone itself. Analysis of men treated with different combinations of hormones of the hypothalamus-pituitary-testis axis suggests that the production of INSL3 is related to LH in a manner similar to that of the LH-testosterone axis

Insulin-like factor 3: A novel circulating hormone of testis origin in humans

Insulin-like factor 3 (INSL3) is a member of the relaxin-insulin family, and it is expressed in pre- and postnatal Leydig cells of the testis. This peptide affects testicular descent during embryonic development, and mutations in INSL3 gene or its receptor LGR8 (leucine-rich repeat-containing G protein-coupled receptor 8)/GREAT (G protein-coupled receptor affecting testicular descent) cause cryptorchidism in humans. The expression of LGR8/GREAT in different tissues and the production of INSL3 also by adult-type Leydig cells suggest additional roles of this hormonal system in adulthood. In this preliminary report we performed the first analysis in humans of INSL3 using a novel RIA kit to measure INSL3 concentrations in serum of normal men and with different testicular pathologies. The results show that INSL3 is circulating in adult men, and it is almost exclusively of testicular origin. Subjects with severe testicular damage, such as men with severe infertility, produce low amount of INSL3, and the concentrations of this hormone seem to reflect the functional status of the Leydig cells. In particular, INSL3 concentrations may be an even more sensitive marker of Leydig cell function than testosterone itself. Analysis of men treated with different combinations of hormones of the hypothalamus-pituitary-testis axis suggests that the production of INSL3 is related to LH in a manner similar to that of the LH-testosterone axis

A novel missense mutation in the L1CAM gene in a boy with L1 disease

A novel missense mutation of the L1CAM gene (Xq28) is described in an adult patient affected with severe mental retardation, spastic paraparesis, adducted thumbs, agenesis of corpus callosum and microcephaly (L1 disease). We detected a transition c2308G-->A in exon 18 that caused an amino acid change in codon 770. The patient's mother and two sisters were heterozygous for the same mutation. This newly described mutation predicts the substitution of an aspartate by asparagine (D770N) in the second fibronectin (Fn2) domain of the extracellular portion of the mature L1 protein. Even if amino acid substitution does not significantly change the physico-chemical properties of the Fn2 domain, it seems clear that the integrity of this domain is required to maintain the biological functions of the protein. The feature peculiar to this patient is the decelerated head growth post-natally, leading to microcephaly. Mutations of L1CAM associated with prolonged survival may hamper post-natal brain and head growth

A novel missense mutation in the L1CAM gene in a boy with L1-disease.

A novel missense mutation of the L1CAM gene (Xq28) is described in an adult patient affected with severe mental retardation, spastic paraparesis, adducted thumbs, agenesis of corpus callosum and microcephaly (L1 disease). We detected a transition c2308G-->A in exon 18 that caused an amino acid change in codon 770. The patient's mother and two sisters were heterozygous for the same mutation. This newly described mutation predicts the substitution of an aspartate by asparagine (D770N) in the second fibronectin (Fn2) domain of the extracellular portion of the mature L1 protein. Even if amino acid substitution does not significantly change the physico-chemical properties of the Fn2 domain, it seems clear that the integrity of this domain is required to maintain the biological functions of the protein. The feature peculiar to this patient is the decelerated head growth post-natally, leading to microcephaly. Mutations of L1CAM associated with prolonged survival may hamper post-natal brain and head growth