Point mutations detected in the androgen receptor gene of three men with partial androgen insensitivity syndrome.

OBJECTIVE: Determine the sequence of the androgen receptor gene in men with impaired responsiveness to androgens in order to identify the molecular basis of their under-virilization. DESIGN: Blood samples were used as the source of genomic DNA. Portions of the androgen receptor gene were amplified by polymerase chain reaction and sequenced. PATIENTS: Samples were obtained from three patients and five normal fertile controls. Patients were all 46 XY and were undervirilized with ambiguous external genitalia, gynaecomastia and infertility. MEASUREMENTS: Total cellular DNA was purified from peripheral blood leucocytes. Pairs of oligonucleotide primers designed to flank the individual exons of the androgen receptor gene were synthesized. The specific regions of the androgen receptor were amplified from the samples of cellular DNA by polymerase chain reaction. Amplified DNA was purified, sequenced and compared to the published sequence. RESULTS: In all three patients point mutations in the androgen receptor gene were detected but no defects were detected in samples from normal controls. In two of the patients, an identical single nucleotide change from G to T was detected. This nucleotide was within the codon for amino acid 866 and would change it from valine to leucine. Amino acid 866 is found within an area of the steroid binding domain thought to be involved in receptor dimerization. Within the repetitive sequence of exon I patient 1 had 21 glutamine residues and patient 2 had 25. In the third patient a single change of G to A would result in incorporation of lysine in place of a conserved arginine residue at position 607 within the second zinc finger of the DNA binding domain. The sequence of the androgen receptor gene of the mother of the third patient revealed her to be heterozygous for the same defect. CONCLUSION: Patients 1 and 2 are unrelated although they have an identical point mutation in their androgen receptor gene. A patient with complete androgen insensitivity syndrome has been reported to have a defect at the same position causing the amino acid substitution of methionine for valine. Therefore we confirm that the nature of the amino acid change in the peptide sequence of the androgen receptor as well as its location within the protein, can have a profound effect on the phenotypic severity of androgen resistance. Studies on mutated receptors from individuals with a wide range of degrees of androgen resistance may enable us to construct a map of the key amino acids in the different domains of the protein.

Circulating CA-195 in hepatocellular carcinoma and metastatic hepatic carcinoma.

This study was conducted to determine the role of a relatively new tumor marker, CA-195, in the diagnosis of hepatocellular carcinoma and metastatic hepatic carcinoma, and in distinguishing between these two conditions. CA-195 levels were measured using a commercially available immunoradiometric assay (Tandem-R CA-195) in 30 black inpatients with hepatocellular carcinoma, 15 metastatic carcinoma, 10 with amoebic liver abscess, 10 with cirrhosis and 10 normal individuals at King Edward VIII Hospital, Durban. A cutt-off value of 10 u/ml was used. The sensitivity and specificity of CA-195 in hepatocellular carcinoma and metastatic carcinoma was 60% and 22%, and 87% and 42% respectively. False positive results occurred in 5 (50%) patients with amoebic liver abscess, 10 (100%) with cirrhosis and 2 (20%) normal individuals. These results indicate this tumor marker as of limited value in the diagnosis of hepatocellular carcinoma and metastatic carcinoma, and in distinguishing between these conditions.

Pituitary function tests in black patients with pseudocyesis.

Pituitary function was evaluated in a group of 10 patients with pseudocyesis. One patient was postmenopausal; the remainder demonstrated normal basal prolactin, luteinising hormone (LH) and follicle-stimulating hormone (FSH) levels and also normal pituitary-adrenal, pituitary-thyroid axes. Oestradiol deficiency was present in 6 patients, while 2 patients demonstrated elevated serum progesterone values, suggestive of a luteal phase. Gonadotrophin-releasing hormone administration resulted in exaggerated stimulation of LH and FSH in 4 and 2 patients, respectively. Impaired growth hormone (GH) secretion was present in 6 patients after insulin-induced hypoglycaemia and L-dopa administration. GH impairment is probably a consequence of the oestrogen deficiency that commonly occurs in this condition. It thus appears that there are aberrations in specific pituitary hormone responses after provocation in pseudocyesis.

Enzyme immunoassay of oestrogen and progesterone receptors in uterine and intrauterine tissue during human pregnancy and labour.

Oestrogen and progesterone receptors were studied in the non-pregnant state, in early pregnancy and at term using monoclonal antibody enzyme immunoassays. Receptors for both steroids were found in tissues from non-pregnant patients and patients in early pregnancy. At term oestrogen receptors were undetectable in all tissues studied. Progesterone receptors were undetectable in chorion, amnion and placenta at term, while present in extremely low concentrations in decidua and myometrium.

Changes in the binding characteristics of oestrogen and progesterone in uterine and intrauterine tissue with the progression of human pregnancy.

The binding characteristics of oestrogen and progesterone in intrauterine tissue were studied in the non-pregnant state and throughout pregnancy using sucrose density gradient centrifugation and titration analyses. High affinity receptors for these steroids which were present in high concentrations in tissue from non-pregnant patients and patients in early pregnancy, decreased with the advance of pregnancy to undetectable levels at term. Non-saturable binding to progesterone detected in term tissue was identified as albumin and cortisol binding globulin.

Termination of pregnancy with mifepristone after intra-uterine death. Clinical and hormonal effects.

Mifepristone was used in a dosage of 400 mg/d in a double-blind study to induce labour in patients with intra-uterine fetal death in late pregnancy. Eight of 12 patients who received the drug delivered within 72 hours while only 2 of 12 patients treated with placebo delivered during a similar period. No adverse effects, viz. excessive vaginal bleeding and abnormal biochemical or haematological parameters, were associated with the use of this drug.

Serial oxytocin levels in amniotic fluid and maternal plasma during normal and induced labour.

Oxytocin was measured by a specific and sensitive radioimmunoassay in plasma and amniotic fluid after extraction with Sep-Pak cartridges in patients undergoing elective caesarean sections, normal labour and labour induced with oxytocin infusion or prostaglandins. In maternal plasma, levels of oxytocin correlated with the period of gestation; concentrations at term were significantly higher than in the first two trimesters. Maternal plasma levels of oxytocin before the onset of contractions were not significantly different from those at the onset of spontaneous labour or at full cervical dilatation. Levels of oxytocin in patients induced with oxytocin were not statistically different from levels observed in spontaneous labour. Amniotic fluid oxytocin levels were not significantly different between the groups either at the onset of labour or immediately before delivery. Umbilical arterio-venous differences in oxytocin were present in all groups except the prostaglandin-induced group. Increased prostaglandins associated with the onset of normal labour are probably not a consequence of changes in oxytocin concentrations.

Hypogonadotrophic variant of Klinefelter's syndrome. A case report.

A 16-year-old boy with 47,XXY chromosomal complement (Klinefelter's syndrome) presented with delayed puberty and apparent gonadotrophin deficiency. Despite an inadequate growth hormone response to insulin-induced hypoglycaemia and to L-dopa administration, his somatic growth was appropriate for his delay in pubertal development, increasing markedly on testosterone treatment. Patients with Klinefelter's syndrome may have abnormalities of neuro-endocrine regulation.

Evidence for increased absorption of glucose and decreased hepatic extraction of insulin in South African Indians.

It has been previously demonstrated that Indians have an exaggerated insulin response to oral glucose when compared to Africans. In an attempt to determine the reasons for this phenomenon matched groups of Indian and African volunteers were subjected to oral and intravenous glucose tolerance testing. It was concluded that the increased absorption of glucose and reduced hepatic extraction of insulin contributed to the hyperinsulinism in Indians.

Decreased concentrations and affinities of oestrogen and progesterone receptors of intrauterine tissue in human pregnancy.

Cytoplasmic and nuclear receptors for oestrogen and progesterone were measured in non-pregnant myometrium and endometrium and compared to concentrations found in decidua of ectopic pregnancy (6-8 weeks gestation) and therapeutic abortions (8-16 weeks). Amnion, chorion, placenta, decidua and myometrium at full term pregnancy were also assayed for the same receptors. High affinity binding was confirmed in the non-pregnant tissue; in early pregnancy, decreases in concentrations of cytoplasmic receptors were demonstrated, these decreases becoming more marked as pregnancy progressed in the 1st trimester. Nuclear receptor concentrations were not significantly different. Significant decreases in the occurrence of positive receptors with the progression of pregnancy were also demonstrated for cytoplasmic and nuclear oestrogen and nuclear progesterone receptors. Tissue at full term pregnancy had no detectable receptors, irrespective of whether the patients were in labour or not. Increasing the range of the labelled steroids failed to demonstrate any low affinity binding sites and pre-assay removal of endogenous hormones also had no effect on receptor status. When endogenous hormones were removed, displaceable binding was demonstrated in the presence of excess unlabelled ligand. However, this binding did not conform with receptor dynamics on Scatchard analysis. Heating the cytosol prior to assay or failure to remove endogenous steroid hormones eliminated this binding. Cytosolic oestrogen and progesterone levels increased significantly in the decidua of therapeutic abortions, whilst term pregnant tissue had the highest concentration of endogenous hormones.

Changes in amniotic fluid prostaglandins with oxytocin-induced labor.

Amniotic fluid prostaglandin levels were measured serially in 15 patients who underwent successful induction of labor and compared with those of patients presenting in spontaneous labor. At comparable cervical dilation the induced group demonstrated significantly lower prostaglandin levels. Four of these patients delivered without any increment in prostaglandins while in the remaining patients increases in prostaglandins followed the attainment of efficient uterine contractions by several hours. These data support the hypothesis that oxytocin acts directly on myometrial cells and not primarily by prior generation of prostaglandin synthesis in the membranes.