Hydrophilic cyclodextrin derivatives enable effective oral administration of steroidal hormones

Condensation products of beta-cyclodextrin with propylene oxide or epichlorohydrin, which are amorphous and thus very soluble in water, were used to form complexes with testosterone, progesterone, and estradiol. Sublingual/buccal administration of tablets of these complexes led to effective absorption and entry of the hormones into the systemic circulation, followed by gradual elimination; rapid first-pass loss was avoided. beta-Cyclodextrin itself, its 2,6-dimethyl derivative, and a nonionic detergent did not enable effective buccal absorption. Absorption from the GI tract of hormones complexed with hydrophilic cyclodextrins was also less effective. Effective absorption of drugs from the oral cavity requires (a) that the drug and solubilizer form a complex of the inclusion type which dissolves completely and rapidly and (b) that the solubilizer neither enters nor damages oral tissue.

In vivo pretreatment with human chorionic gonadotropin fails to reverse the dysfunction of isolated Leydig cells from chronically uremic rats

In order to further investigate the previously reported hypogonadal state of chronically uremic rats, we examined the effects of in vivo pretreatment with human chorionic gonadotropin (hCG) on in vivo and in vitro Leydig cell function, comparing paired intact rats with rats made chronically uremic by 5/6 nephrectomy. The in vitro testosterone (T) secretory responses to varying concentrations of hCG or dibutyryl cAMP and the number of gonadotropin receptors were determined following hemicastration. The rats were then treated with hCG for 3 days and the remaining testes were removed and studied as before. Compared with intact rats, the uremic rats had higher serum concentrations of urea nitrogen (P less than 0.001); serum T concentrations were lower in uremic rats before (P less than 0.001), but not after (P greater than 0.6) treatment. Treatment produced increases in serum T only in uremic rats (P less than 0.001). Serum LH was lower in uremic rats before treatment (P less than 0.001) and was reduced (P less than 0.001) to similar levels (P greater than 0.8) in both groups after treatment. Baseline in vitro T secretion was lower (P less than 0.001) from Leydig cells of uremic than intact rats both before and after treatment. Analysis of variance of dose-response curves showed pre- and post-treatment T secretory responses to hCG or dibutyryl cAMP in vitro to be less from Leydig cells of uremic rats (P less than 0.01). Before treatment, Leydig cell gonadotropin receptor number was lower in uremic than intact rats (P less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Decreased in vitro secretion of LH, FSH, and free alpha-subunits by pituitary cells from old male rats

Various in vivo and in vitro pituitary-Leydig cell functions were examined in mature (5-8 mo) vs. old (22-25 mo) male Wistar rats. Old rats exhibited decreased serum concentrations of testosterone, luteinizing hormone (LH), and follicle-stimulating hormone (FSH) (P less than 0.0025) but similar levels of prolactin (P less than 0.01) both before and 4 wk after castration. The in vitro release of LH, FSH, and free alpha-subunits was measured in primary cultures of dispersed anterior pituitary cells from both intact and castrated rats. During 48 h of incubation, basal secretion rates of the glycoproteins were decreased (P less than 0.001) from cells of both intact and castrated old rats. After stimulation with LH-releasing hormone (LRH) in single (10(-8) M) or multiple (10(-10) - 10(-7) M) doses, the total amounts of the glycoproteins secreted were also less from cells of both intact and castrated old rats. However, repeated measures analysis of variance revealed age-related hyporesponsivity to LRH stimulation only for LH secretion by cells from intact rats. The basal molar ratios of alpha/(LH + FSH) secreted by cells from intact but not castrated old rats were lower than those from cells of the corresponding mature rats. Moreover, after LRH stimulation (10(-10) - 10(-7) M), molar secretory ratios of alpha/(LH + FSH) decreased from cells of intact mature rats but increased from cells of intact old rats. These in vitro data suggest that the reduced serum LH and FSH levels in intact and castrated old male rats result in part from decreased secretion of these glycoproteins.(ABSTRACT TRUNCATED AT 250 WORDS)

In vivo chorionic gonadotropin administration reverses the testosterone secretory defect of Leydig cells from old rats

Old male rats have decreased serum testosterone, luteinizing hormone (LH), follicle -stimulating hormone (FSH), Leydig cell testosterone secretory responsiveness to chorionic gonadotropin (hCG), and gonadotropin binding capacity. Although prolonged in vivo hCG administration restores serum testosterone, in vitro hCG exposure of Leydig cells does not reverse their age-related hyporesponsiveness. To explore this discrepancy, we studied Leydig cell function before and after hCG administration in vivo (treatment). Before treatment, old rats had lower serum testosterone, in vitro testosterone and cyclic adenosine monophosphate (cAMP) production, both basally and in response to hCG, and reduced hCG binding capacity. After treatment, old and young rats did not differ in any of these parameters. hCG binding and cAMP responses were reduced in both old and young rats. Thus, prolonged in vivo exposure to hCG appeared to reverse both the in vivo and in vitro age-related Leydig cell secretory defect, despite gonadotropin receptor down-regulation. This suggests that the "aging" defect(s) are caused by chronic gonadotropin deprivation.

Pituitary-thyroid hormone economy in healthy aging men: basal indices of thyroid function and thyrotropin responses to constant infusions of thyrotropin releasing hormone

In order to assess the effects of aging, as distinct from those of thyroid disease or extrathyroidal illness, on certain indices of thyroid function, we studied 74 healthy, ambulatory men recruited from the Baltimore Longitudinal Study on Aging. We determined basal serum values of T4, T3, rT3, thyroxine-binding globulin (TBG), and T3 resin uptake (T3RU) and calculated the free T4 index (FT4I = T4 X T3RU/100), free T3 index (FT3I = T3 X T3RU/100), and T4/TBG ratio for each subject. We used an ultrasensitive RIA to measure variations in basal concentrations of TSH within the normal range. We then infused TRH at a constant rate (0.4 microgram/min iv) for 240 min into 63 of the same men; serum samples, collected at 15-min intervals during the infusion, were analyzed for TSH by routine RIA. Subjects were divided into 3 groups according to age; A (n = 26, mean age = 39.4), B (n = 23, mean age = 60.0), and C (n = 25, mean age = 79.6). Analysis of variance with Duncan's multiple range test and regression analysis were used to evaluate data. There was no significant (P greater than 0.05) variation with age of basal serum values of T4, TBG, or T3RU. Comparison of groups A and C showed significant decreases of mean values of serum T3 (-11%, P less than 0.05), FT3I (-13%, P = 0.02), FT4I (-11%, P less than 0.01), and T4/TBG ratio (-12%, P less than 0.01) and an increase in serum TSH (+38%, P less than 0.05). For these variables, the mean values for group B were intermediate between, but not significantly different from, those of A and C. Regression analysis showed significant correlations of age with T3, FT3I, FT4I, T4/TBG, and TSH at P levels similar to those obtained by Duncan's test. No elderly individual exhibited a baseline elevation of TSH (greater than 7 microU/ml) or depression of T4 (less than 5 micrograms/dl), suggesting that primary hypothyroidism was not present in our old group. The basal TSH concentration did not correlate significantly with any index of thyroid function except with FT3I in group C (r = -0.43, P less than 0.05). In all age groups the TSH responses to TRH exhibited a biphasic pattern with early and late peaks.(ABSTRACT TRUNCATED AT 400 WORDS)

The egg-embryo chamber for intraabdominal culture

We have developed a novel semipermeable chamber for intraabdominal culture of primate gametes and embryos. Application of the egg-embryo chamber offers a unique opportunity to study fertilization and preimplantation embryogenesis. Intrinsically normal monkey embryos displayed timely cleavage and symmetric form when cultured in this intraabdominal chamber for up to 72 hours. The birth of the first normal live monkey infant derived from the egg-embryo chamber is reported.

Relationship of serum testosterone to sexual activity in healthy elderly men

There are reports of decreases in both sexual activity and serum testosterone in older men but not of any clear association between the two variables. In healthy participants in the Baltimore Longitudinal Study on Aging, despite the fact that serum testosterone did not decline with age, sexual activity decreased in a highly predictable fashion. In men over 60 years old, those with higher levels of sexual activity (for age) had significantly greater levels of serum testosterone. Although we found an inverse correlation between testosterone and percentage of body fat, there was no relationship between percentage of body fat and sexual activity. We also found no correlation between testosterone or sexual activity and smoking or coronary heart disease. Subjects drinking more than 4 oz. of ethanol per day were more likely to have decreased sexual activity but not diminished testosterone concentration. Our data suggest that, although serum testosterone level and ethanol intake may affect sexual activity in older men to some degree, age itself still appears to be the most influential variable.

Reproductive hormones in aging men. II. Basal pituitary gonadotropins and gonadotropin responses to luteinizing hormone-releasing hormone

Although basal serum LH and FSH levels have been shown to increase with age in men, there is evidence that aging may impair pituitary gonadotropin secretion to some extent. We have measured serum LH and FSH before and after the iv injection of 100 micrograms LRH in 69 healthy men, divided into 3 age groups: A (25-49 yr; n = 24), B (50-69 yr; n = 23), and C (70-89 yr; n = 22). We have previously demonstrated these men to have unaltered serum androgens and estrogens over the entire age range. Only log-transformed measures were analyzed in order to equalize variance among groups. Because we found increasing age to be associated with significant rises in basal levels of LH and FSH, and because the basal level affects the magnitude of response, we used repeated measures analysis of variance to compare LRH peak responses with basal gonadotropin levels. The presence of a significant interaction term would indicate an effect of age on response beyond that expected from the effect of basal level alone. The mean LRH responses (log peak--log basal) decreased, with significant interaction terms for both LH (P = 0.001) and FSH (P less than 0.0001) responses. This means that the function relating basal to peak gonadotropin concentrations changed significantly with age. Peak LH responses in the youngest group (A) occurred equally as often 15 and 30 min after LRH injection, but in the oldest group (C) there were no 15 min peaks, and 40% of the peak values occurred at 60 min (P less than 0.01). FSH peaks were equally distributed at 30, 60, and 120 min in all 3 groups. Total testicular volumes did not decrease significantly with age. We conclude that there is a small but statistically significant tendency for LH and FSH responses to LRH to be both diminished and delayed in healthy aging men. The mechanisms responsible for this apparent pituitary gonadotropic hypofunction remain to be clarified.

Evaluation of pituitary gonadotropic function in men: value of luteinizing hormone-releasing hormone response versus basal luteinizing hormone level for discrimination of diagnosis

We examined the serum LH response to LRH in 40 normal men and 38 men with various forms of gonadal dysfunction in an attempt to determine whether the LH response to LRH was more useful than the basal LH level alone for categorizing pathophysiological subgroups of gonadal dysfunction. The subgroups studied included hypogonadotropic hypogonadism, delayed puberty, idiopathic oligospermia, and primary hypogonadism. Log transformation of all values was done in order to normalize the data. Spearman's correlation analysis showed that increased basal LH was associated with increased incremental LH responses. However, our preliminary analysis of LRH response data suggested that the changes in LH were smaller in the secondary hypogonadal and delayed puberty groups then could be accounted for by the differences in basal LH level. Accordingly, we used various statistical techniques to test whether, and under what conditions, LRH testing provides information beyond that evident from examination of basal LH values. We found that the relationship between basal LH and the LH response to LRH differs in men with and without hypothalamic-pituitary dysfunction and that this difference can be exploited to improve the discrimination of men with pituitary hypogonadism from normals.

Convenient radioimmunoassay for urinary human choriogonadotropin without interference by urinary human lutropin

We have devised a radioimmunoassay (RIA) for human choriogonadotropin (hCG) in first morning-voided urine specimens. Concanavalin A, a lectin, is used to extract and concentrate the hCG from urine. A high-affinity antiserum is used, directed to the hCG beta carboxy-terminal peptide, a unique immunological determinant not shared by the beta subunit of human lutropin. This ensures that urinary human lutropin-related molecules, which interfere with RIAs involving antisera to the intact hCG beta subunit, will not cross react in this assay. A concentrations of hCG as low as 0.4 microgram/L can be detected in the first morning-voided urine. The effective sensitivity of this assay for the unequivocal detection of hCG production is somewhat better than that achieved with the serum hCG RIA involving antisera to the hCG beta subunit. The improved specificity and sensitivity of this assay, and the greater convenience of collecting samples of urine rather than blood, are clinical useful advantages of this approach to assessing hCG production in humans.

Convenient radioimmunoassay for urinary human choriogonadotropin without interference by urinary human lutropin

We have devised a radioimmunoassay (RIA) for human choriogonadotropin (hCG) in first morning-voided urine specimens. Concanavalin A, a lectin, is used to extract and concentrate the hCG from urine. A high-affinity antiserum is used, directed to the hCG beta carboxy-terminal peptide, a unique immunological determinant not shared by the beta subunit of human lutropin. This ensures that urinary human lutropin-related molecules, which interfere with RIAs involving antisera to the intact hCG beta subunit, will not cross react in this assay. A concentrations of hCG as low as 0.4 microgram/L can be detected in the first morning-voided urine. The effective sensitivity of this assay for the unequivocal detection of hCG production is somewhat better than that achieved with the serum hCG RIA involving antisera to the hCG beta subunit. The improved specificity and sensitivity of this assay, and the greater convenience of collecting samples of urine rather than blood, are clinical useful advantages of this approach to assessing hCG production in humans.

Advantage of Florisil over charcoal separation in a mechanized testosterone radioimmunoassay

We have facilitated radiommunoassay of testosterone by mechanizing every pipetting step and separating bound from free hormone by shaking assay tubes with activated magnesium silicate (Florisil) in a multi-tube Vortex mixer. Compared with dextran-charcoal separation, Florisil separation has the advantage that testosterone is only negligibly adsorbed except during active shaking, so that the interval for adding adsorbent does not produce discrepancies in bound hormone estimates between first and last assay tubes in a series. Our method gave CVs of 5% (within assay) and 6% (between assay) for samples containing 4.0 mug of testosterone per liter, considerably better than those obtained with charcoal (respectively 12 and 15%). The assay also had low blank values and demonstrated excellent accuracy.

Advantage of Florisil over charcoal separation in a mechanized testosterone radioimmunoassay

We have facilitated radiommunoassay of testosterone by mechanizing every pipetting step and separating bound from free hormone by shaking assay tubes with activated magnesium silicate (Florisil) in a multi-tube Vortex mixer. Compared with dextran-charcoal separation, Florisil separation has the advantage that testosterone is only negligibly adsorbed except during active shaking, so that the interval for adding adsorbent does not produce discrepancies in bound hormone estimates between first and last assay tubes in a series. Our method gave CVs of 5% (within assay) and 6% (between assay) for samples containing 4.0 mug of testosterone per liter, considerably better than those obtained with charcoal (respectively 12 and 15%). The assay also had low blank values and demonstrated excellent accuracy.

Reproductive hormones in aging men. I. Measurement of sex steroids, basal luteinizing hormone, and Leydig cell response to human chorionic gonadotropin

Although alterations of circulating sex steroids have been reported in aging men, it is not known to what extent reported changes may represent effects of variables other than aging. We have measured sex hormone levels, serum binding, the testosterone (T) response to hCG, and basal LH levels in 69 male volunteers, aged 25-89 yr, without alcoholism, obesity, chronic illness, or severe prostatic disease, and not using potentially interfering medications. In our study there was no effect of age on serum T, 5 alpha-dihydrotestosterone, estrone, or estradiol. Binding of T to T-binding globulin increased slightly with age, but not enough to decrease the free T index (fraction free X T concentration). Basal serum LH rose significantly. The T response to hCG suggested a somewhat diminished Leydig cell reserve with age, a conclusion consistent with the LH elevation. Our failure to detect the decreased T and free T index or increased estrogens reported by others could reflect afternoon rather than morning sampling, but is more likely to be due to our use of exceptionally healthy volunteers. We suggest that factors other than aging might have influenceed the data previously reported, and that aging per se need not be associated with altered sex steroid levels in the human male.

Depressed plasma testosterone and fractional binding of testosterone in obese males

Plasma testosterone (T), fractional binding of T to T-binding globulin (TeBG), LH, and FSH were evaluated in 22 obese men. Only 1 of 12 men weighing from 176-200% of ideal body weight (group I) had a low T concentration, while 9 of 10 men greater than 200% of ideal weight (group II) had plasma T concentrations 2 SD below the normal mean. The fractional binding of T to TeBG was equally and significantly decreased in both groups. As a result, the mean and individually calculated free T concentrations (free T index) were normal in group I. In contrast, the mean free T index in group II was significantly less than normal males and group I. Individually, 1 of 7 group II men had a free T index 2 SD below the normal mean. LH and FSH were normal in both groups. These studies indicate that in most obese males a low or low normal T is offset by decreased binding to TeBG, resulting in a normal free T index. However, some morbidly obese males are unable to alter their hypothalamic-hypophyseal-gonadal axis to maintain a normal free T index.

Testosterone secretion in the rat in response to chorionic gonadotrophin: alterations with age

It has been reported by others that both prevailing blood concentrations of testosterone and Leydig cell response to gonadotrophin (up to 1 h after injection) are reduced in the aged male rat. Although resting levels of plasma testosterone in our aged (24-26 months old) Sprague-Dawley rat are also depressed compared with young (3-4 months) or mature (12 months) animals of the same strain, subcutaneous injection with human chorionic gonadotrophin for 3 days restores secretory function, producing testosterone levels indistinguishable from those of similarly stimulated younger rats. In short term experiments, old rats did show a diminished testesterone secretory response to human chorionic gonadotrophin 1 h after a single intravenous injection, consistent with previous reports, but restoration of normal stimulated levels was observed by 2 h, and persisted up to 24 h. These findings differ from the demonstrated intrinsic testicular hyporesponsiveness to gonadotrophin of aged men, and probably represented a state of chronic understimulation of the aged rat Leydig cells, due to low prevailing levels of LH.

Rapid measurement of an index of testosterone binding to serum binding globulin using ion exchange columns

DEAE cellulose "mini" columns at pH 7.4 retain testosterone (T) bound to testosterone binding globulin (TeBG), which can be eluted at pH 2. Small 1:2 diluted serum or plasma samples are incubated with a tracer dose of tritiated T in pH 7.4 Tris buffer at 37 C then chilled and placed on columns at 4 C. Free and albumin bound T are washed off columns with pH 7.4 Tris buffer and columns are eluted with pH 2 Tris into vials for scintillation counting. After a simple mathematical correction for the small residual fraction of albumin bound T eluted at pH 2, we obtain a measure of TeBG binding of T which is highly correlated (r = .945) with that determined by dialysis. The method is quick, reproducible and applicable to serum or plasma volumes of 50 to 200 microliter. A single operator can process 100 samples in approximately 4 h.

Follicle stimulating activity of human chorionic gonadotropin: effect of dissociation and recombination of subunits

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.

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.