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Biomedical subjects

W C Hobson

Publications and source records attributed to W C Hobson.

23 records · Page 2Linked to original sources
PubMed1977

Biotransformation of diethylstilbestrol in the rhesus monkey and the chimpanzee.

Diethylstilbestrol (DES) is considered a teratogen and a transplacental carcinogen in humans. In order to compare its biotransformation in nonhuman primates to that in humans, a metabolic study was carried out in rhesus monkeys and chimpanzees. After an oral dose of 1 mg/kg [14C]DES, approximately 59% of the ingested radioactivity was found in the urine and 28% in the feces of two female rhesus monkeys after 4 days, while in male rhesus monkeys urinary radioactivity accounted for 43% and fecal radioactivity for 35%. In chimpanzees, 63% of a 0.5 mg/kg dose was excreted with the urine in a female and 47% in a male animal. In both species, urinary radioactivity was predominantly (greater than 70%) associated with glucuronides. Besides DES, three metabolites were found in the urinary glucuronide fraction of rhesus monkeys and chimpanzees by radio gas chromatography and were identified as dienestrol and omega-hydroxy derivatives of DES and dienestrol. Fecal radioactivity in rhesus monkeys was shown to consist exclusively of DES. Glucuronidation of DES appears to occur in neonatal and fetal rhesus monkeys.

Animals↗
PubMed1975

Serial serum levels of gonadotropins, prolactin and sex steroids in the nonpregnant and pregnant chimpanzee.

Serum levels of FSH, LH, chorionic gonadotropin (CG), prolactin, estrone (E1), estradiol-17Beta (E2), estriol (E3) and progesterone were measured at 2-3-day intervals in 4 chimpanzees through 2-3 menstrual cycles, and serially through subsequent pregnancies. The hormone patterns of the menstrual cycles were similar to those in man, with high levels of FSH in the early follicular phase, followed by rising E2 concentrations to a peak (up to 35 ng/dl) at or just before a midcycle LH/FSH peak. In most cycles there was a secondary E2 rise and progesterone rose to values above 500 ng/dl during the luteal phase. There was no consistent pattern in prolactine levels through 3 menstrual cycles. A simultaneous increase in E2 and LH/CG levels and a fall in FSH about 10 days postovulation indicated fertilization and implantation. Other early signs of pregnancy were persistent luteal range progesterone concentrations and rising levels of E1 and E3. Peak CG levels (56-154 IU/ml) occurred 30-50 days after the midcycle LH/FSH peak, followed by a decline and then a small secondary rise to (to 1 IU/ml) before term. E1, E2 and E3 levels rose more rapidly after 80 days to a peak at term (E1: 180-300 ng/dl; E2: 500-800 ng/dl; and E3:400-1000 ng/dl). Progesterone levels showed one peak coincident with the CG peak, and a secondary rise after about 80 days to maximal values at term of 49-120 ng/ml. Prolactin levels increased during pregnancy with irregular fluctuations (7-127 ng/ml). These findings indicate in contrast to observations in rhesus monkeys and baboons, that the hormonal patterns during pregnancy in the chimpanzee are remarkably similar to those in man. Thus, the chimpanzee should prove to be an ideal model for research directly applicable to human reproduction.

Animals↗
PubMed1975

Pituitary-gonadal relations in infancy. I. Patterns of serum gonadotropin concentrations from birth to four years of age in man and chimpanzee.

Mixed cord sera (27 male, 28 female) and sera from 105 male and 93 female children aged 5 days to 4 yr were assayed for FSH, LH and hCG. Cord hCG was similar in both sexes (median 58 mIU/ml; range 20-9000), and fell to less than 5 mIU/ml by 5 days of life, a value which is below the limit of detectable cross reactivity in the LH radioimmunoassay. Cord FSH was less than 5.5 mug LER-907/100 ml in both sexes. In boys there was a rapid rise of FSH in early postnatal life, with peak levels up to 55 mug/100 ml between 1 week and 3 months, followed by a decline by 4 months reaching the low values seen in older prepubertal subjects. This postnatal FSH rise was both more marked in females with peak values at 2-3 months up to 169 mug/100 ml, and also more sustained with levels staying above those of older prepubertal children until 4 yr of age. Serum LH levels in the boys were in the adolescent range by 1 week of age, peaked at 1 month and then declined to the usual childhood range by 4 months. A similar pattern, though with lower peak LH values, was seen in the female infants. A longitudinal study of serum FSH and LH values in one male and one female chimpanzee from 17 to 456 days of age showed patterns in serum gonadotropins which paralleled those seen in the human cross-sectional study.

Age Factors↗
PubMed1975

Radioimmunoassay for rhesus monkey gonadotropins.

Heterologous double-antibody radioimmunoassay methods are described for the measurement of circulating levels of rhesus monkey (Macaca mulatta) FSH and LH; the latter assay is also applicable to rhesus chorionic gonadotropin (CG) estimations. The FSH assay utilizes purified rat FSH for trace, either of two anti-human FSH antisera and a semipurified rhesus pituitary standard. The LH assay utilizes purified ovine LH for trace, an anti-human CG antiserum and the same rhesus pituitary standard. The use of these systems obviates the necessity of purifying rhesus gonadotropins which are required for the development of homologous radioimmunoassay systems.

Animals↗