Biomedical subjects
Publications and source records attributed to G T Ross.
Human chorionic gonadotropin (hCG) has been studied extensively over the past 10 years, and some structural correlates of its chemical, biological, and immunologic properties have been defined. A review of these observations and their relevance to clinical applications of methods for detecting hCG is presented.
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Progesterone (P) production by isolated rat granulosa cells from preantral follicles was enhanced by addition of androgens to the tissue culture medium. Testosterone (T) at 10(-7), 10(-6), and 10(-4)M as well as 10(-6)M dihydrotestosterone (DHT) increased P production 400 to 700% over paired control cultures. Human chorionic gonadotropin (100 mIU/ml) and 17beta-estradiol (7.8 X 10(-10M) had no effect on P production. P was identified by both a specific radioimmunoassay and sephadex LH-20 column chromatography. The stimulatory influence of T and DHT on these preantral follicular cells is consistent with a direct role for androgens in granulosa cell differentiation.
The influence of testosterone (T) on progesterone (P) production by isolated rat ovarian granulosa cells was studied in vitro using a new replicate culture technique. Preantral granulosa cells from ovaries of estrogen-primed hypophysectomized immature female rats were cultured in the presence of graded concentrations of T, diethylstilbestrol (DES), cyproterone acetate (CPA), flutamide and the hydroxylated derivative of flutamide, Sch 16423. The accumulation of P in medium collected from granulosa cell cultures was measured by specific radioimmunoassay. Maximal P production by cultured granulosa cells was attained during the second day of culture and declined markedly thereafter. The presence of 10(-9), 10(-8) or 10(-7)M T elicited increases in P production 2.4, 8 and 11 times that of controls, respectively, during the initial 48 h of culture. Each concentration of T elicited enhanced P production within the first 24 h of culture. Granulosa cells cultured in control medium for 2 days did not respond to 10(-7)M T during the subsequent 3 days. DES at a high concentration in the medium (10(-5)M) markedly suppressed the response to 10(-9) and 10(-8)M T. At a lower concentration (10(-9)M) DES significantly enhanced the stimulatory effect of 10(-9)M T but did not alter the response to higher concentrations of T. Neither high nor low concentrations of DES influenced P production in response to 10(-7) M T. The stimulatory effects of T on P production were suppressed in the presence of a 100-fold molar excess of the anti-androgens, CPA or Sch 16423. The present data indicate that androgenic stimulation of P production by preantral granulosa cells is a specific receptor mediated event which is modulated by the presence of estrogen in vitro. It is suggested that androgen-responsive P production is a functional capacity which granulosa cells acquire at a very early stage of hormonal differentiation and may be of physiological consequence in the intraovarian control of follicular maturation in vivo.
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Ovarian biopsies from five women with the syndrome of hypogonadotropic hypogonadism and anosmia who had not previously received exogenous gonadotropins were evaluated with special emphasis on follicular morphology. Follicular development past the primordial stage was rarely observed, suggesting that early stages of follicular maturation require amounts of gonadotropins in excess of those secreted in these women.
Two cases of recurrent trophoblastic disease are presented in which human chorionic gonadotropin was detected in assays of urine concentrates at a time when serum levels were undetectable by a sensitive and specific beta-subunit radioimmunoassay. The potential greater usefulness of measurements of urinary concentrates is discussed.
Fifty-eight women who conceived following successful chemotherapy of gestational trophoblastic neoplasms subsequently became pregnant a total of 96 times. Seventy-eight of these 96 pregnancies or 81% terminated in live-born infants. Fifteen of the 96 or 16% ended in abortion and three or 3% terminated with stillborn infants. Among the live-born and stillborn infants there were three with congenital malformations classified as major. While this incidence of congenital malformations does not appear to be increased over that expected, the numbers are too small to perceive a two-fold increase in the expected incidence. Suggestions are made for improvements in the quality of these data.
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Substances from urinary extracts of normal, nonpregnant subjects and human pituitary gonadotropin preparations were found to react similarly to human chorionic gonadotropin (hCG) in a radioimmunoassay system that is highly specific for hCG and without crossreactivity to human luteinizing hormone (hLH). The antiserum was produced in a rabbit immunized with a bovine albumin conjugate of the unique carboxyl-terminal peptide (residues 123-145) isolated from a tryptic digest of the reduced, S-carboxymethylated hCGbeta subunit. The antibody recognition site on the peptide was found to reside on the last 15 amino acid residues of the carboxyl-terminal peptide, as evidenced by the competitive binding activities against 125I-labeled hCG of a series of peptides chemically synthesized according to the carboxyl-terminal sequence of HCGbeta. In order to elucidate the nature of the crossreacting substance in urinary extracts, a human postmenopausal urinary preparation (Pergonal) and a kaolin-acetone extract of urine from a patient with Klinefelter's syndrome were subjected to gel chromatography on Sephadex G-100. The results indicate that fractions showing immunocrossreactivity with the antiserum to hCGbeta-carboxyl-terminal peptide coeluted with 125I-labeled hCG which was separated distinctly from hLH. The same fractions from this postmenopausal urinary gonadotropin preparation exhibited in vitro biological activity proportional to the immunocrossreactivity of the hCG-specific antiserum. Concentration of postmenopausal women's urine by acetone precipitation retained approximately five times more immunoreactivity per unit volume than kaolin-acetone extraction, when assayed with the antiserum to hCGbeta-carboxyl-terminal peptide.
A soluble thermolabile protein with many characteristics of an androgen receptor has been demonstrated for the first time in the cytosol (100,000 X g supernatant) of estrogen-stimulated ovaries from hypophysectomized immature female rats (HIFR) treated with diethylstilbestrol in Silastic capsules (DESC). This binding protein is organ-specific and androgen-specific, has a high affinity with a Kd of 2.4 X 10(-9)M for testosterone, and is saturable with 2.1 X 10(-13) moles of binding sites per mg cytosol protein. The number of binding sites is linear with cytosol protein concentration and the binding protein sediments at 7-8 S on sucrose gradients. Estradiol is an effective inhibitor of testosterone binding. A role for this testosterone-binding protein as an effector of ovarian morphologic change is hypothesized.
A sensitive and specific radioimmunoassay system for macaque follicle-stimulating hormone (mFSH) was developed utilizing an antiserum (H-31) prepared in a rabbit against purified ovine FSH as the immunogen. Sera from castrated female, adult male, and juvenile rhesus monkeys, as well as urinary extracts from castrated rhesus and bonnet monkeys, were used to demonstrate parallelism with a standard of partially purified monkey pituitary gonadotropins (LER-M-907-D). An extract of baboon pituitary tissue also showed parallelism with the reference standard. A highly purified pituitary extract (WP-X-105-28), containing approximately 75% macaque luteinizing hormone (mLH) and 1% mFSH, was used to demonstrate the specificity of this mFSH assay system. Sera and urinary extracts obtained from hypophysectomized monkeys did not show cross-reactivity in the assay. Macaque chorionic gonadotropin (mCG) did not produce an inhibition curve in the assay, as determined from serum samples and urinary extracts collected from pregnant monkeys at the time of peak mCG secretion. Serum concentrations of mFSH were suppressed in ovariectomized monkeys by the administration of ethinyl estradiol for 3 days, but returned to near pretreatment values by 96 h after the last estradiol administration. The determination of serum mFSH concentrations in daily blood samples obtained from 20 rhesus monkeys throughout ovulatory menstrual cycles revealed a pattern similar to that previously reported for the rhesus monkey and the woman. The peak value of serum mFSH during the menstrual cycle coincided with the midcycle surge of mLH in each case. The gonadotropin peaks were preceded by increasing serum concentrations of estradiol and followed by rises in the serum concentrations of progesterone. The follicular phase of the menstrual cycle was characterized by continuously decreasing serum concentrations of mFSH, reaching a preovulatory nadir 48 h prior to the midcycle mFSH and mLH surges. Serum mFSH concentrations following the midcycle gonadotropin surges decreased progressively as serum progesterone concentrations increased and reached a plateau, and then increased during the last week of the menstrual cycle as corpus luteum function was waning. We have prepared a large pool of antiserum for distribution under the aegis of the Contraceptive Development Branch of the Center for Population Research, the National Institute of Child Health and Human Development.
We have recently described receptor like testosterone (T)-binding protein in the cytosol of ovaries from estrogen-primed hypophysectomized immature female rats (HIFR). This binding protein is thermolabile, saturable, specific for T, and sediments at 7-8 S on sucrose gradients. We now report the further characterization of this protein. It is present in the cytosol of isolated granulosa cells, has a molecular weight of 240,000, a frictional ratio of 1.8, and a mean Stokes radius of 73 A. The binding protein is acidic and cysteine residues are necessary for binding. We have also demonstrated the selective nuclear accumulation of T by granulosa cells after the in vivo administration of (3H)T to estrogen primed HIFR. After the in vitro incubation of the ovaries with (3H)T, a thermolabile protein specific for T was extracted from nuclei under high-salt conditions. The cytosol and nuclear T-binding proteins described in this report have many characteristics of an androgen receptor, and may play a role in the regulation of granulosa cell proliferation during preantral follicular growth.
The follicle stimulating activity (FSA) and interstitial cell stimulating activity (ICSA) of highly purified human chorionic gonadotropin (hCG), its alpha and beta subunits, and hCG generated by subunit recombination were determined by ovarian weight and ventral prostate weight bioassays. Whereas highly purified hCG exhibited both FA and ICSA, its separated subunits were essentially devoid of both activities. ICSA and FSA, indistinguishable from that of the highly purified hCG, were restored by recombination of the hCG subunits. These observations are consistent with the hypothesis that the FSA and ICSA found in highly purified hCG preparations are properties of the hCG molecule.
Luteal phases of an abbreviated duration or suboptimal progesterone secretion were identified in the rhesus monkey. Characterization of menstrual cycles with short luteal phases (8 days) in 5 monkeys revealed the following deviations from normal: a. a failure of serum FSH to decline progressively from an early follicular phase high to a preovulatory nadir; b. a commonly inadequate, or absent, preovulatory FSH surge; c. subnormal serum LH concentrations during both the follicular and luteal portions of the menstrual cycle; d. ratios of serum FSH:LH which did not progressively decrease during the follicular phase; and e. serum estradiol concentrations below normal values during the luteal portion of the menstrual cycle. One monkey had abnormally low serum concentrations of progesterone, although the luteal phase was 19 days in duration. Serum gonadotropin and estradiol patterns in this latter monkey were identical to those observed in monkeys with short luteal phases. It is concluded that inappropriate ratios of serum FSH:LH during the follicular phase of the menstrual cycle result in impaired corpus leteum function. The data document the usefulness of the nonhuman primate for investigating those luteal phase defects which also occur in the woman.
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