We have examined the human growth hormone (hGH) and human chorionic somatomammotropin (hCS) family of genes in genomic DNA from an individual with complete antenatal deficiency of hCS. Following digestion with a variety of bacterial restriction endonucleases, the DNA from this individual produced fewer fragments with homology to a radiolabeled hCS cDNA probe than did control DNA specimens. The patterns indicated that his DNA contained the normal hGH gene and an "hGH-like" gene, but lacked the hCS gene, a variant hGH gene, and another gene or genes with structural homology to hGH and hCS, which were present in all control DNA specimens. The findings were consistent with homozygosity for a gene deletion with a minimum length of 18.5 kb. Analysis of polymorphic restriction site variation related to the hGH and hCS gene cluster indicated that both parents and three older siblings were heterozygous for the deletion. The association between gene deletion and a normal growth pattern in this individual indicates that hCS and any other peptide hormones encoded by the variant hGH and the other related gene(s) that are deleted in this individual are not required for fetal or extrauterine growth.
A rare tumor, primary choriocarcinoma of the stomach, occurred in a post menopausal female. The diagnosis was confirmed by autopsy and by immunohistochemical demonstration of HCG in trophoblastic tumor cells. Theories concerning development of this neoplasm are briefly discussed. In addition, this postmenopausal case uniquely permitted examination of the hormonal effects of the tumor on target tissues without the clouding issue of normal menstrual hormones. It appears that the observed estrogen- and progesterone-related tissue responses were not mediated through the ovary; instead, direct tumor production of these hormones is implicated.
Placentae or uteri from pregnant rats (days 12-21) contained no detectable alpha-subunit of the glycoprotein hormones (CG, TSH, FSH, and LH) when assayed in either a rat or human alpha-RIA. The heads of rat fetuses contained increasing concentrations of alpha-subunit when assayed from days 12-20 of gestation (7.2-46 ng/g). Human term placenta contained large quantities of alpha-subunit (16,000 ng/g). alpha-Subunit was synthesized by the cell-free translation of poly(A)-enriched mRNA from mouse TSH-secreting pituitary tumor and human term placenta, but not from rat placentae or uterine implantation sites (days 11-21 of gestation). In addition, alpha mRNA was detected in mouse TSH-secreting pituitary tumor, rat pituitary, and human term placenta by hybridization to a 32P-labeled mouse alpha cDNA probe although no alpha mRNA could be detected in rat placentae (days 13-21 of gestation). The luteotropic activity found in pregnant rodents must be caused by a substance with a structure substantially distinct from any known gonadotropin.
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