Origin of iridescent colors on the indigo snake.

In the indigo snake, a pattern of undulating lines on the surface of the skin, formed by the junction of rows of cells, acts as a two-dimensional optical diffraction grating to produce the play of colors. The distance between repetitive units of the pattern measured from observations made with an electron microscope are in agreement with those found by spectrometric analysis.

Sex steroid modulation of fatty acid utilization and fatty acid binding protein concentration in rat liver.

The mechanism by which sex steroids influence very low density hepatic lipoprotein triglyceride production has not been fully elucidated. In previous studies we showed that [(14)C]oleate utilization and incorporation into triglycerides were greater in hepatocyte suspensions from adult female rats than from males. The sex differences were not related to activities of the enzymes of triglyceride biosynthesis, whereas fatty acid binding protein (FABP) concentration in liver cytosol was greater in females. These findings suggested that sex differences in lipoprotein could reflect a sex steroid influence on the availability of fatty acids for hepatocellular triglyceride biosynthesis. In the present studies, sex steroid effects on hepatocyte [(14)C]oleate utilization and FABP concentration were investigated directly. Hepatocytes from immature (30-d-old) rats exhibited no sex differences in [(14)C]oleate utilization. With maturation, total [(14)C]oleate utilization and triglyceride biosynthesis increased moderately in female cells and decreased markedly in male cells; the profound sex differences in adults were maximal by age 60 d. Fatty acid oxidation was little affected. Rats were castrated at age 30 d, and received estradiol, testosterone, or no hormone until age 60 d, when hepatocyte [(14)C]oleate utilization was studied. Castration virtually eliminated maturational changes and blunted the sex differences in adults. Estradiol or testosterone largely reproduced the appropriate adult pattern of [(14)C]oleate utilization regardless of the genotypic sex of the treated animal. In immature females and males, total cytosolic FABP concentrations were similar. In 60-d-old animals, there was a striking correlation among all groups (females, males, castrates, and hormone-treated) between mean cytosolic FABP concentration on the one hand, and mean total [(14)C]oleate utilization (r = 0.91) and incorporation into triglycerides (r = 0.94) on the other. In 30-d-old animals rates of [(14)C]oleate utilization were greater, relative to FABP concentrations, than in 60-d-old animals. The sex differences that characterize fatty acid utilization in adult rat hepatocytes are not present in cells from immature animals, and reflect in part the influence of sex steroids. It remains to be determined whether the observed relationship of hepatic FABP concentration to [(14)C]oleate utilization in adult cells is causal or secondary to changes in cellular fatty acid uptake effected through another mechanism. In either case, modulation of triglyceride-rich lipoprotein production by six steroids appears to be mediated to a significant extent by their effects on hepatic fatty acid utilization.

Regulatory perspective on clinical trials and end points for female sexual dysfunction, in particular, hypoactive sexual desire disorder: formulating recommendations in an environment of evolving clinical science.

This article examines the history, current status, and potential future challenges in the development of drugs for female sexual dysfunction (FSD) from the perspective of the United States Food and Drug Administration. In particular, the article focuses on testosterone therapy for hypoactive sexual desire disorder (a component of FSD), and the role of the Division of Reproductive and Urologic Products in facilitating the development of safe and effective therapies for this indication.

Conservation of free but not total or non-sex-hormone-binding-globulin-bound testosterone in serum from Nagase analbuminemic rats.

Nagase analbuminemic rats have normal reproductive capacity, normal apparent libido, and normal serum concentrations of LH and FSH. Therefore, it is reasonable to assume that intracellular sex steroid hormone concentrations are normal or at least adequate to maintain normal reproductive function in these rats. To test whether intracellular testosterone concentrations in these rats are maintained by the circulating concentration of free or free-plus-weakly-bound testosterone, we measured the concentrations of total testosterone, free testosterone, and non-sex-hormone-binding-globulin-bound testosterone in sera from five adult male Nagase analbuminemic rats and from five age- and sex-matched controls. We found that the analbuminemic rats had markedly decreased serum concentrations of total and non-sex-hormone-binding-globulin-bound testosterone, but normal serum concentrations of free testosterone. These results suggest that intracellular concentrations of testosterone in biologically relevant organs of the rat are maintained by the concentration of free rather than free-plus-weakly-bound testosterone in plasma, in accord with the free hormone hypothesis.

Prolactin concentrations in the monkey fetus during the last third of gestation.

PRL concentrations were measured in cord plasma obtained at hysterotomy from 26 rhesus monkey fetuses between 111--170 days gestational age (GA). Mean PRL concentrations increased significantly from 23.7 +/- 10.1 (X +/- SE) ng/ml at 121--130 days GA to 126.9 +/- 16.9 ng/ml at 161--170 days GA. A similar significant increase in PRL with age also was observed in samples obtained from 16 fetuses chronically catheterized in utero between 130--155 days GA. Mean PRL levels were 34 +/- 3.2 ng/ml at 131--140 days GA and rose to 82 +/- 9.7 at 150--155 days GA. No difference in PRL concentrations was found between cord blood samples and fetal peripheral blood samples at the ages studied. Maternal PRL levels did not change in samples obtained from chronically catheterized, chair-restrained mothers between 130--155 days GA. A tendency toward an increase in maternal PRL with advancing gestational age was observed in samples collected after hysterotomy. These data indicate that the fetal rhesus monkey demonstrates an increase in plasma PRL similar to that in the human, suggesting a possible physiological role for this hormone in the primate fetus late in gestation.

Treatment of hirsutism with a gonadotropin-releasing hormone agonist (nafarelin).

GnRH analogs inhibit the secretion of gonadotropins and, therefore, that of estrogens and androgens of ovarian origin. The purpose of this study was to investigate the use of one superactive agonistic GnRH analog, nafarelin, in the treatment of hirsutism. Six hirsute women were treated with nafarelin (1 000 micrograms/day) for 6 months. An acute rise in serum gonadotropin levels occurred in response to nafarelin administration initially, but it lasted less than 2 weeks. Serum gonadotropin, testosterone, free testosterone, and androstenedione concentrations decreased significantly during treatment. Mean serum LH levels decreased from 17.9 +/- 4.6 (+/- SE) to 5.0 +/- 0.5 mIU/ml (P less than 0.01), and FSH decreased from 9.3 +/- 0.7 to 7.2 +/- 0.9 mIU/ml (P less than 0.05) after 1 month of treatment. The total testosterone concentration fell from 0.77 +/- 0.10 to 0.40 +/- 0.14 ng/ml (P less than 0.01) after 1 month of therapy, and free testosterone decreased from 10.7 +/- 2.7 to 4.1 +/- 1.6 pg/ml (P less than 0.01) after 3 months. Androstenedione levels decreased from 2.4 +/- 0.4 to 1.2 +/- 0.2 ng/ml (P less than 0.01) after 1 month of treatment. The mean concentrations of all of the above hormones remained suppressed throughout treatment. Serum 5 alpha-androstane-3 alpha,17 beta-diol glucuronide levels did not decrease significantly during treatment, nor did dehydroepiandrosterone sulfate levels. The mean estradiol concentration during treatment was 34.8 +/- 3.1 pg/ml. The clinical response was very good; hair growth was slower, and new hair was less coarse compared to the pretreatment period. Hirsutism scores (determined by Ferriman-Gallwey assessment of extent and quality of body hair) improved in four of the six patients. In the six patients, the mean score decreased significantly from 19.3 +/- 3.3 to 13.2 +/- 2.8 (P less than 0.05) at the end of treatment. These data demonstrate that by suppressing ovarian androgen production, nafarelin may be useful for the treatment of hirsutism associated with either increased ovarian androgen production or increased sensitivity of the hair follicle to normal concentrations of circulating androgens.

Variable ovarian response to gonadotropin-releasing hormone antagonist-induced gonadotropin deprivation during different phases of the menstrual cycle.

The gonadotropin dependence of ovarian follicular maturation and corpus luteum function can now be examined in women using antagonistic analogs of GnRH. We studied the responses of three groups of women throughout a control cycle and during the administration of a potent GnRH antagonist, detirelix ([N-Ac-D-Nal(2)1,D-pCl-Phe2,D-Trp3,D-hArg(Et2)6,D-Ala10++ +] GnRH, Syntex Research). Detirelix (10 mg, sc) was administered for 3 consecutive days during the midfollicular phase (n = 4), preovulatory phase (n = 4), and early luteal phase (n = 4). The pituitary response to detirelix was similar throughout the three phases of the menstrual cycle. Immunoreactive LH concentrations decreased to 35% (mean +/- SEM) of pretreatment values within 8 h after the initial injection and remained suppressed for 72 h after discontinuance of treatment. Immunoreactive FSH concentrations decreased to 73 +/- 3% of pretreatment levels within 8 h and returned to baseline within 24 h after the third injection. In contrast, the ovarian response to detirelix varied markedly during different phases of the cycle. Midfollicular phase treatment was associated with a decline in estradiol (E2) levels from pretreatment values of 246 +/- 48 to 81 +/- 15 pmol/L within 24 h of the last injection. Vaginal bleeding ensued in three of four women. Follicular recruitment was then reinitiated, and an ovulatory LH surge occurred 18.2 +/- 2.9 days after the last injection. Similarly, treatment during the early luteal phase produced a decline in E2 concentrations from 286 +/- 29 to 70 +/- 7 pmol/L and a decline in progesterone concentrations from 20 +/- 1.6 to 1.9 +/- 0.3 nmol/L within 24 h after the last injection. Luteolysis was associated with menstrual bleeding in all four women. The subsequent ovulatory LH surge occurred 16.5 +/- 1.0 days after discontinuance of treatment. In contrast, treatment during the preovulatory phase resulted in a decline in E2 concentrations from 844 +/- 66 to 429 +/- 132 pmol/L during the first 48 h of treatment. Gonadotropin and E2 concentrations subsequently recovered from suppression, growth of the dominant follicle resumed, and a LH surge occurred 5.8 +/- 1.4 days after the last injection. These data indicate that the GnRH antagonist detirelix produces rapid and consistent suppression of pituitary gonadotropin secretion. The magnitude of suppression and preferential suppression of LH vs. FSH are similar throughout the cycle. In contrast, the ovarian response to gonadotropin deprivation varies during the menstrual cycle.(ABSTRACT TRUNCATED AT 400 WORDS)

Inhibition of follicular development by a potent antagonistic analog of gonadotropin-releasing hormone (detirelix).

The ability of a potent long-acting antagonistic analog of GnRH to suppress gonadotropin secretion, disrupt follicular development, and inhibit ovulation was studied in six women with normal menstrual cycles. The GnRH antagonist detirelix ([N-Ac-D-Nal(2)1,D-pCl-Phe2,D-Trp3,D-hArg(Et2)6,D-Ala10++ +] GnRH; Syntex Research) was administered to six women by sc injection on alternate days during a 27-day period. Six additional women underwent blood sampling only, without receiving detirelix. Within 8 h after the initial injection of detirelix, mean (+/- SEM) serum LH and FSH concentrations decreased by 74 +/- 2% and 26 +/- 3%, respectively. Mean immunoreactive FSH levels, however, returned to baseline after the first 72 h despite continued administration of detirelix. Mean estradiol (E2) concentrations decreased from 165 +/- 15 to 70 +/- 11 pmol/L in the first 24 h. During the treatment period follicular development was inhibited, and none of the six volunteers showed evidence of ovulation, as assessed by serum progesterone (P) levels. Maximal suppression of serum LH and E2 was observed approximately 24 h after each injection of detirelix. Compared to the control volunteers, those receiving detirelix had significantly lower mean serum LH (P less than 0.001), E2 (P less than 0.001), and P (P less than 0.001) levels during treatment; mean FSH concentrations, however, were not statistically different in the treatment and control groups. Rapid recovery of pituitary-ovarian function occurred after completion of treatment. In all six volunteers receiving detirelix, a LH surge occurred 10-16 days after the final injection, followed by increased P levels (greater than 32 nmol/L), indicating ovulation and a luteal phase of normal duration (12-14 days). Detirelix injections elicited local skin reactions (erythema and pruritus), but no systemic side-effects were observed. Thus, this long-acting GnRH antagonist can rapidly suppress gonadotropin secretion, inhibit follicular development, and prevent ovulation.

Dose-dependent inhibition of pituitary-ovarian function during administration of a gonadotropin-releasing hormone agonistic analog (nafarelin).

To determine if treatment with the GnRH agonistic analog nafarelin could reliably block ovulation while only partially disrupting ovarian estrogen production, three degrees of pituitary-ovarian inhibition were investigated. Thirty-two women with ovulatory menstrual cycles were given 125 micrograms (group (Gp) I), 250 micrograms (Gp II), or 1000 micrograms (Gp III) nafarelin daily by intranasal spray. Twenty-seven women completed 6 months of treatment. Basal serum FSH concentrations decreased (P less than 0.01) in all groups. Suppression of serum LH was dose dependent and significant (P less than 0.01) only in Gps II and III. Pituitary desensitization to nafarelin developed in all groups. Peak LH responses to nafarelin decreased by about 70% (Gps I and II) and 95% (Gp III). Basal serum estradiol levels after 1 month of treatment were approximately 70 pg/ml (Gp I) and 25 pg/ml (Gps II and III). Serum estradiol levels increased acutely in Gps I and II, but not in Gp III, in response to each dose of nafarelin. Thus, average daily estradiol levels in Gp II were higher than those in Gp III. Serum testosterone and androstenedione levels decreased slightly (P less than 0.05; Gp II) or by 50% (P less than 0.01; Gp III) during treatment. The effects of nafarelin on ovulatory function also were dose-dependent. In Gp I there were four ovulations (progesterone, greater than 4 ng/ml) and seven instances of luteinization (progesterone, 2-4 ng/ml) during 73 months of nafarelin administration. In contrast, there were no ovulations during 58 and 44 months in Gps II and III, respectively. After discontinuance of nafarelin, ovulatory menstrual function returned rapidly in all women. In summary, inhibition of pituitary-ovarian function by daily intranasal nafarelin administration is dose dependent. Gonadotroph sensitivity to 125 micrograms is variable, and there is inconsistent inhibition of ovulation. Daily doses of 250 or 1000 micrograms analog reliably inhibit ovulation, but are associated with either moderate (Gp II) or marked (Gp III) reduction of ovarian estradiol secretion. The effects of these reduced levels of circulating estradiol on bone are not known. Further investigation, with dosage adjusted according to individual patient sensitivity, may lead to the development of a clinically acceptable contraceptive which consistently inhibits ovulation while maintaining serum estradiol levels sufficient to prevent osteoporosis.

Endocrine effects and pharmacokinetic characteristics of a potent new gonadotropin-releasing hormone antagonist (Ganirelix) with minimal histamine-releasing properties: studies in postmenopausal women.

A potent and safe GnRH antagonist has been sought unsuccessfully for the last 2 decades. The recently developed GnRH antagonist RS-26306 or Ganirelix ([N-Ac-D-Nal(2)1,D-pClPhe2,D-Pal(3)3,D-hArg(Et2)6,L-++ +hArg(Et2)8,D-Ala10]GnRH ; Syntex Research, Palo Alto, CA), exhibited high antiovulatory potency and low histamine-releasing properties in preclinical studies. Therefore, we determined the extent to which single sc injections of three doses of RS-26306 (1, 3, and 6 mg) decreased serum concentrations of LH and FSH, the free alpha-subunit of LH/FSH/TSH, PRL, and testosterone in five healthy postmenopausal women. We also examined the pharmacokinetic characteristics of RS-26306 by quantifying serum levels of the drug by RIA. RS-26306 rapidly suppressed serum concentrations of LH, FSH, and free alpha-subunit. RS-26306 (6 mg) maximally decreased serum concentrations (mean +/- SEM) of LH, FSH, and free alpha-subunit by 70.1 +/- 3.6%, 42.3 +/- 2.5%, and 74.6 +/- 3.5%, respectively. RS-26306 also decreased serum testosterone, but not serum PRL, concentrations. RS-26306 concentrations reached peak serum levels at 1.2 +/- 0.3, 1.9 +/- 0.4, and 1.8 +/- 0.5 h, respectively, after 1-, 3-, and 6-mg sc injections. The mean serum half-life values based on the terminal portion of the disappearance curves were 22.8 +/- 2.5 and 26.9 +/- 1.0 h, respectively, after 3- and 6-mg s.c. doses. No systemic side-effects were noted after the administration of RS-26306. Our results demonstrate that the GnRH antagonist RS-26306 has favorable pharmacokinetic characteristics and is a potent suppressor of pituitary gonadotropin secretion in postmenopausal women. These attributes and the lack of systemic side-effects make RS-26306 a promising candidate for future clinical applications.

Concordant suppression of serum immunoreactive luteinizing hormone (LH), follicle-stimulating hormone, alpha subunit, bioactive LH, and testosterone in postmenopausal women by a potent gonadotropin releasing hormone antagonist (detirelix).

The purposes of the current study were 2-fold: 1) to assess the effects of a new antagonistic analog of GnRH [N-Ac-D-Nal(2)1, D-pC1-phe2, D-Trp3, D-hArg (Et2)6, D-Ala10] GnRH, or detirelix (Syntex Research) on gonadotrope function as reflected by serum levels of immuno- and bioassayable LH, and immunoactive FSH and alpha-subunit concentrations in postmenopausal, hypergonadotropic women; and 2) to determine if androgen production in the postmenopausal ovary is gonadotropin dependent. Six normal postmenopausal women were studied. Each volunteer received doses of 1, 5, and 20 mg detirelix sc in a random order separated by at least a 1-week interval. Serum LH, FSH, and alpha-subunit were measured by RIA at frequent intervals for 72 h after each injection. Bioactive LH levels were measured at 0, 24, 48, and 72 h after injection by a mouse Leydig cell bioassay, to permit comparison of biological with immunological LH activity. The steroids testosterone (T) and dehydroepiandrosterone sulfate were measured before injection and 12 (T only), 24 and 48 h after injection of the 20 mg dose. Immunoactive levels of serum LH and FSH were both suppressed in a dose-dependent manner, but LH suppression was greater than that of FSH. Maximum LH suppression (mean +/- SEM) after the 1, 5, and 20 mg doses was 40.2 +/- 7.0%, 63.2 +/- 3.4%, and 75.8 +/- 2.2%, respectively. For the same doses, maximum FSH suppression was 18.0 +/- 6.0%, 25.6 +/- 4.6%, and 39.6 +/- 2.7%. LH levels remained suppressed below baseline for up to 72 h after the 20 mg dose. Bioactive LH changes closely paralleled those of immunoactive LH. Mean LH suppression (area under the serum concentration curve) during the first 24 h after injection was 23.5 +/- 6.2% for the 1-mg dose, 47.2 +/- 4.7% for the 5-mg dose, and 61.0 +/- 2.1% for the 20-mg dose. Mean percent FSH suppression during the first 24 h, calculated in the same manner, was 6.8 +/- 3.9% (1 mg), 14.5 +/- 2.9% (5 mg), and 18.2 +/- 2.6% (20 mg). Serum alpha-subunit concentrations were significantly suppressed by 1 h after dosing with the 5- and 20-mg doses (P less than 0.05), and remained suppressed throughout the 72-h sampling period. Gonadotropin dependence of steroidogenesis in the postmenopausal ovary was suggested by a significant suppression of serum T concentrations after the 20-mg dose of detirelix.(ABSTRACT TRUNCATED AT 400 WORDS)

Stimulation of LH fragments with reduced bioactivity following GnRH agonist administration in women.

In eumenorrheic women with endometriosis and in oligo-amenorrheic women with polycystic ovarian disease (PCO), chronic administration of a long-acting GnRH agonist (GnRH-a) reduced the circulating concentrations of estrogens and androgens to levels similar to those of castrated women. The concommittant elevation of LH in both groups suggested that the measured immunoreactive LH had reduced bioactivity. In seven women with endometriosis, bioactive LH (BA LH) measured as the in-vitro secretion of testosterone by dispersed Leydig cells, was significantly (p less than 0.001) reduced from 10.8 +/- 1.2 (SEM) to 4.4 +/- 0.2 mIU/ml at the end of 28 days of GnRH-a therapy. In five women with PCO, BA LH decreased from 44.2 +/- 15.5 to 5.7 +/- 0.6 mIU/ml (p = 0.06). These changes of BA LH appeared to be responsible for the suppression of ovarian androgen secretion during GnRH-a treatment and in turn may have contributed to the profound decreases of estrogen production by reducing the amount of precursor androgen available for aromatization. Free alpha subunit levels increased simultaneously with the decrease of BA LH at the end of therapy, suggesting a post-receptor effect of GnRH-a. Beta subunit levels became undetectable. Cross-reaction of alpha subunit in the RIA for LH was sufficient to only partially account for the LH levels measured. On sephadex G-100 chromatography the excess immunoreactive material was detected at and immediately following the alpha subunit tracer. Further studies will be necessary to elucidate the chemical nature of the immunoreactive LH secreted during GnRH-a therapy.

Prolactin-secreting adenomas in women. VII. Dopamine regulation of prolactin secretion.

Previous studies demonstrated that high doses of dopamine administered as a constant infusion were capable of suppressing PRL secretion in both normal and hyperprolactinemic individuals. The present study was designed to examine the dose-response relationship of PRL suppression to low doses of dopamine (between 0.06 and 4 micrograms/kg X min) infused in a step-wise fashion. Ten hyperprolactinemic patients with PRL-secreting pituitary adenomas and 10 normally menstruating women in the early follicular phase of a cycle were studied. For hyperprolactinemic women, the mean (+/- SD) serum PRL level (by RIA) was 112 +/- 101 ng/ml, with a range of 26-386 ng/ml, the mean estradiol level (by RIA) was 28 +/- 8 pg/ml, and the mean baseline dopamine level by carboxy-o-methyl transferase assay (COMT) was 357 +/- 237 pg/ml (2.33 +/- 1.54 X 10(-9) M). The normal women had a mean PRL of 8.1 +/- 3.5 ng/ml, a mean estradiol level of 42 +/- 12 pg/ml, and a mean baseline dopamine level of 317 +/- 223 pg/ml (2.07 +/- 1.45 X 10(-9) M). Concentrations of dopamine achieved at the lowest doses infused were less than 10 times baseline levels and were in the nanomolar range. The measured IC50 (the concentration of dopamine required to achieve 50% of maximal suppression) was 6 +/- 3 X 10(-9) M for normal women and 14 +/- 4 X 10(-9) M for hyperprolactinemic patients. The apparent inhibition constant determined by a nonlinear least squares procedure, was 3 +/- 3 X 10(-9) M for normal women and 11 +/- 12 X 10(-9) M for women with hyperprolactinemia. Both groups exhibited dose-dependent suppression of PRL to about 80% of initial values. Under these experimental conditions, the data do not support the hypothesis that there is a marked loss in sensitivity to dopamine in patients with PRL-secreting adenomas.

Induction of ovulation in the postpartum rhesus monkey: factors determining success in obtaining primate luteal tissue.

Ovulation induction in the postpartum rhesus monkey was attempted with the use of purified human pituitary gonadotropins for assessment of (1) whether this procedure could be used to provide a source of luteal tissue; (2) the extent of ovarian responsiveness to gonadotropic stimulation; (3) factors that might facilitate ovulation induction during the peurperium; and (4) factors that might be a contributory cause of induction failure. Twenty rhesus monkeys were treated with purified human follicle-stimulating hormone (hFSH) and human luteinizing hormone (hLH) twice daily, beginning on days 0, 10, or 20 postpartum, with or without prior administration of bromocriptine. Laparotomies were performed during the midluteal phase. Ovaries were examined, and all corpora lutea were removed. Neither the day of beginning the gonadotropin treatment nor bromocriptine administration had a significant effect on the success rate of ovulation induction, which averaged 60% overall. Inductions begun during July had a significantly (P less than 0.025) lower success rate than those started at other times of the year. Antibodies to hFSH and hLH were detected in serum from monkeys that had undergone ovulation induction. Antibodies to hFSH, but not hLH, were associated with significantly reduced induction success (P less than 0.05). Plasma estradiol rose in response to gonadotropin treatment, and the induced follicular phase averaged 13.6 +/- 0.7 days. In all animals judged to have ovulated, corpora lutea were observed at laparotomy, and plasma concentrations of progesterone were significantly elevated (13.8 +/- 3.8 ng/ml).(ABSTRACT TRUNCATED AT 250 WORDS)

Treatment of endometriosis with a potent agonist of gonadotropin-releasing hormone (nafarelin).

Administration of superactive agonistic analogs of gonadotropin-releasing hormone (GnRH) has been shown to induce a paradoxic and reversible suppression of gonadotropins, resulting in suppressed gonadal steroid concentrations. Because there currently is no uniformly successful and acceptable medical therapy for endometriosis, we examined the effects of 6 months of nasal administration (500 micrograms every 12 hours) of the agonistic analog of GnRH, nafarelin, on clinical signs and symptoms and hormonal profiles in eight women with endometriosis. All patients had prompt and near-complete relief from their painful symptoms of endometriosis. Laparoscopy or laparotomy, performed both before and after treatment in seven of the women, revealed complete resolution of active endometriotic lesions in five patients and only a single, small cul-de-sac implant in a sixth woman. A large ovarian endometrioma decreased slightly in response to treatment in the seventh woman. Serum luteinizing hormone and follicle-stimulating hormone concentrations, after a transitory stimulation at the onset of treatment, declined and were suppressed (P less than 0.001) during the remainder of treatment. Serum estradiol concentrations fell to approximately menopausal levels (less than 30 pg/ml) after 1 to 4 weeks. Reversibility of drug effect was prompt, with ovulatory menses returning 47 +/- 8 days (+/- standard deviation) after treatment. Thus, nasal administration of agonistic analogs of GnRH may represent a new treatment modality for endometriosis.

Contrasting effects of a gonadotropin-releasing hormone agonist and antagonist on the secretion of free alpha subunit.

Gonadotropin-releasing hormone agonists and antagonists have initial divergent effects on the pituitary secretion of intact biologically active gonadotropins and long-term divergent effects on the secretion of free alpha-subunit. The antagonists appear to function as true competitive inhibitors, blocking the stimulatory effects of endogenous GnRH without evoking any known postreceptor activity. The agonists, in contrast, initially stimulate pituitary secretion and then incompletely desensitize the gonadotrope, resulting in suppression of intact gonadotropin, but not free alpha-subunit, secretion. The mechanisms by which GnRH-a produce this incomplete gonadotrope desensitization and facilitate limited postreceptor activity remain to be elucidated.

Suppression of follicular phase pituitary-gonadal function by a potent new gonadotropin-releasing hormone antagonist with reduced histamine-releasing properties (ganirelix).

OBJECTIVE: To determine if daily subcutaneous doses of ganirelix will suppress and maintain E2 < or = 30 pg/mL (conversion factor to SI unit, 3.671), the serum profiles of LH and FSH during and after cessation of treatment, the time-course of the resumption of normal ovarian function after ganirelix cessation, and to identify side effects of daily treatment. DESIGN: Open-label nonrandomized clinical study. SETTING: Normal human volunteers in an academic research center. PATIENTS: Women 21 to 45 years of age, with documented ovulatory menstrual cycles. INTERVENTIONS: Ganirelix was administered subcutaneously daily for 8 days. Blood samples were obtained during dosing as well as before and after cessation of dosing. MAIN OUTCOME MEASURES: Changes in serum E2, LH, FSH, P, and ganirelix. RESULTS: Ganirelix treatment rapidly decreased serum levels of gonadotropins and E2 after both 1 and 2 mg administration. Twenty-four hours after the first dose of ganirelix, E2 decreased from a mean +/- SEM of 50 +/- 8 and 67 +/- 11 pg/mL at baseline to 25 +/- 4 and 20 +/- 3 in the 1 mg and 2 mg groups, respectively. Estradiol remained suppressed (mean levels < 26 pg/mL) on all subsequent 7 days of ganirelix dosing in both groups. After the final dose of ganirelix, there was a rapid return of ovarian function in all volunteers. All women had P levels indicative of ovulation in the subsequent cycle, and the mean number of days from the final ganirelix dose to the next menses was 25.8 +/- 2.1 and 27.3 +/- 1.6 in the 1 and 2 mg groups, respectively. CONCLUSIONS: Daily ganirelix administration is effective in suppressing the pituitary-gonadal axis and has a side effect profile that should be well tolerated.

Dose-related suppression of serum luteinizing hormone in women by a potent new gonadotropin-releasing hormone antagonist (Ganirelix) administered by intranasal spray.

OBJECTIVE: To determine if the GnRH antagonist (GnRH-a) Ganirelix (Syntex Research, Palo Alto, CA), administered by intranasal (IN) spray to normal women, is absorbed into the systemic circulation and suppresses LH secretion. DESIGN: A single center, open label, nonrandomized, dose-escalation study. SETTING: Academic research environment. PATIENT(S): Normal female volunteers ages 23 to 43 years. INTERVENTION(S): Ganirelix was administered as a single dose by IN spray. The administered doses and the number of women receiving each of them were 0.1 mg (n = 1), 0.3 mg (n = 1), 1 mg (n = 2), 3 mg (n = 5), and 6 mg (n = 5). Blood samples were collected from -15 minutes to 24 hours after dosing. MAIN OUTCOME MEASURE(S): Serum concentrations of Ganirelix and LH. RESULT(S): Ganirelix was absorbed rapidly. The mean time to maximal serum levels in the 3- and 6-mg groups was 0.67 and 0.53 hour, respectively. Mean serum LH levels were suppressed by > or = 35% relative to baseline from 2 to 12 hours after dosing in both groups. The mean maximal percent decrease in serum LH was -62% (at 8 hours after dosing) and -74% (at 6 hours after dosing) in the 3- and 6-mg groups, respectively. CONCLUSION(S): Single dose IN administration of 3 or 6 mg of Ganirelix suppressed serum LH levels in women, further enhancing the potential clinical utility of this potent GnRH-a. This is the first clinical report of a GnRH-a reducing the secretion of a pituitary gonadotropin when administered by an IN delivery system. Based on the duration and extent of LH suppression observed in this study, Ganirelix, administered by twice daily IN spray, may be effective for the treatment of gonadal hormone-dependent disorders in women.

Effect on corpus luteum function of luteal phase administration of a potent gonadotropin-releasing hormone analog (nafarelin).

Fourteen women with ovulatory menstrual cycles were treated with a superactive agonistic analog of gonadotropin-releasing hormone (6-D-[2-naphthyl]-alanyl)-GnRH (nafarelin). Eight of the women received a single subcutaneous injection of nafarelin during the luteal phase at a dosage of 2, 5, or 100 micrograms for determination of the dose-response and pharmacokinetic characteristics of the drug. All doses stimulated the release of luteinizing hormone (LH) and follicle-stimulating hormone (FSH). Maximal release was obtained with the 5-micrograms dose (mean +/- standard deviation: delta LH = 297 +/- 75 mIU/ml; delta FSH = 29 +/- 7 mIU/ml), and there was no greater release of gonadotropin with the 100-micrograms dose. To investigate the contraceptive potential of nafarelin as a luteolytic agent, six of the women were treated with 100 micrograms of analog by daily injection for 10 days, beginning either 2 to 3 days or 5 to 7 days after ovulation. Gonadotroph desensitization or down-regulation developed within 24 hours, but serum concentrations of LH and FSH did not fall below normal values during treatment. There were no significant changes in mean estradiol or progesterone concentrations. There also was no change in mean length of the luteal phase (13.7 +/- 2.1 days [control] versus 13.6 +/- 1.4 days). Thus, nafarelin, like other superactive analogs of GnRH, does not appear to be clinically useful as a luteolytic agent in contraceptive development.