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Biomedical subjects

G T Ross

Publications and source records attributed to G T Ross.

At least 55 records · Page 3Linked to original sources
PubMed1976

Hormones and preantral follicle growth in women.

Studies of follicular morphology in biopsies of human ovarian tissue obtained from women with a syndrome of hypogonadotropic hypogonadism have been reviewed. Follicular maturation was consistent with that seen in ovarian tissues removed at postmortem examination of infants. Similarly, follicular maturation was inhibited in ovaries of women receiving oral contraceptive preparations consisting of a mixture of an estrogen and a progestogen. Considered together, ovarian morphology in these two states of relative gonadotropin deficiency suggests that initiation and progression of follicular maturation require adequate quantities of gonadotropins. The stimulatory effects of gonadotropin on preantral stages of follicular maturation are mediated by estrogen in rat ovaries. Failure to observe follicular maturation in ovaries of women with a congenital inability to synthesize estrogen in response to stimulation by gonadotropin suggests that the steroid may play a similar role in initiating follicular maturation in women.

Estrogens↗
PubMed1975

Monthly gonadotropin cycles in premenarcheal girls.

Patterns of nocturnal excretion of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) were investigated in 11 girls. Autoregressive digital filtering of low- and high-frequency variations was used to make patterns more apparent. Coincident FSH and LH surges, separated by an interval of 20 to 40 days, were seen in specimens from three of six postmenarcheal girls and three to five premenarcheal girls. This suggests that cyclic hypothalamic-pituitary-ovarian interactions occur before menarche.

Adolescent↗
PubMed1975

Inhibition of the ovarian augmentation reaction by a chemical antiestrogen.

Inhibition by antiestradiol serum of ovarian weight gain and follicular growth in hypophysectomized immature rats given FSH and hCG suggested that gonadotrophin induced endogenous estrogen secretion plays a role in the ovarian augmentation reaction. We have studied the effects of a chemical estrogen antagonist, cis-clomiphene, on ovarian weight response to gonadotrophins in hypophysectomized immature female rats. We found that this antiestrogen inhibits the ovarian response to FSH and hCG. To our knowledge, this is the first demonstration of a direct effect of a chemical antiestrogen on the ovary, a result consistent with a role for intraovarian estrogen in follicular growth.

Animals↗
PubMed1975

Interaction of estrogen and gonadotrophins on follicular atresia.

We have investigated folluclar atresia by giving hypophysectomized immature female rats (HIFR) diethylstibestrol or gonadotrophins with and without the chemical antiestrogen CI-628, making total counts of normal and atretic follicles greater than 125 muM in diameter, and using a simple model to analyze data. Our results show an antiatretic effect of estrogen, independent of its well-documented mitogenic effect on preantral follicles. We have also shown that CI-628 acts as an anti-estrogen to block follicular proliferation, while acting as an estrogen to inhibit atresia. In addition, we have observed an increase in atresia caused by gonadotrophins, in opposition to their estrogen-mediated positive effect on follicular growth.

Animals↗
PubMed1975

Effects of human chorionic gonadotropin, human interstitial cell stimulating hormone and human follicle-stimulating hormone on ovarian weights in estrogen-primed hypophysectomized immature female rats.

In connection with systematic studies of steroid and peptide hormone interactions during follicular growth, we have measured ovarian weight responses to graded doses of highly purified human chorionic gonadotropin (hCG), human interstitial cell stimulating hormone (hICSH)in hypophysectomized immature female rats (HIFR) treated with diethylstilbestrol in silastic capules (desc) implanted subcutaneously. Our results are consistent with earlier reports of enhancement of ovarian weight responses to hCG and FSH. Contrary to results of similar experiments reported by others, we have found that estrogen treatment of HIFR enhanced ovarian weight response to ICSH. In addition, we report for the first time that small doses of hCG and hICSH inhibit ovarian weight responses to estrogen in HIFR. Our observations on effects of small doses of hCG and hICSH and the long-known fact that ovarian interstitial cells are stimulated in HIFR given similar doses of these hormones lead us to hypothesize that ovarian interstitial cell stimulation is involved in the control of follicular maturation.

Animals↗
PubMed1975

Evidence of a role of adrogens in follicular maturation.

In hypophysectomized immature female rats (HIFR), the ovarian weight response to subcutaneously implanted diethylstilbestrol capsules (DESC) is inhibited by small doses of human chorionic gonadotropin (hCG). This effect, reproduced by equivalent doses of interstitial cell stimulating hormone (ICSH) but not by follicle-stimulating hormone (FSH), is inhibited by treatment with antiandrogens. These data implicate gonadotropic stimulation of interstitial cell androgen production in the control of follicular maturation in rats.

Androgens↗
PubMed1975

A new method simplifying collection of serial specimens for gonadotropin determinations.

Patterns of gonadotropin levels have been compared in specimens of serum, 24-h urine collections, and first morning urine voidings collected throughout a menstrual cycle from 8 sexually mature, young women. Quantities of gonadotropins in first morning voidings were found to provide a reliable estimate of 24-h excretion of these hormones and demonstrate the same patterns of change as do serum and 24-h urine specimens. Thus first morning voidings satisfactorily overcome logistical problems inherent is serial serum and 24-h urine sampling for studying gonadotropin excretion patterns.

Adolescent↗
PubMed1975

Method for extraction of glycoprotein hormones from plasma for use in radioimmunoassays.

Concanavalin-A covalently linked to Sepharose was used to extract the glycoproteins from a volume of human plasma about 10 times that volume usually added to conventional radioimmunoassay systems. Using a chorionic gonadoptropin (hCG) radioimmunoassay, hCG inhibition curves generated in the presence of the extracts were nearly identical to those generated by the conventional method; therefore, the sensitivity of the radioimmunoassays for glycoprotein hormones.

Animals↗