Radioimmunoassay method for six steroids in human plasma

A putative corticosteroid hormone in Pacific lamprey, Entosphenus tridentatus

Great efforts have been put forth to elucidate the mechanisms of the stress response in vertebrates and demonstrate the conserved response across different vertebrate groups, ranging from similarities in the activation of the hypothalamic-pituitary-adrenal axis to the release and role of corticosteroids. There is however, still very little known about stress physiology in the Pacific lamprey (Entosphenus tridentatus), descendants of the earliest vertebrate lineage, the agnathans. In this paper we demonstrate that 11-deoxycortisol, a steroid precursor to cortisol in the steroidogenic pathway, may be a functional corticosteroid in Pacific lamprey. We identified the putative hormone in Pacific lamprey plasma by employing an array of methods such as RIA, HPLC and mass spectrometry analysis. We demonstrated that plasma levels of 11-deoxycortisol significantly increased in Pacific lamprey 0.5 and 1 h after stress exposure and that lamprey corticotropin releasing hormone injections increased circulating levels of 11-deoxycortisol, suggesting that the stress response is under the control of the HPA/I axis as it is in higher vertebrates. A comprehensive understanding of vertebrate stress physiology may help shed light on the evolution of the corticosteroid signaling system within the vertebrate lineage.

Temporal Changes Occur in the Neuroendocrine Control of Gonadotropin Secretion in Aging Female Rats: Role of Progesterone1

The present study examined the gonadotropin surge-inducing actions of estradiol (E(2)), both alone and with progesterone (P(4)), in middle-aged, early persistent-estrous (PE) female rats that had become PE within 35 days. In addition, we also assessed the effect of P(4) on the mating-induced gonadotropin surges in these acyclic animals. Early PE rats were ovariectomized and received E(2) implants (Day 0). On Day 4, an s.c. injection of P(4) (0.5 mg/ 100 g body weight) at 1200 h markedly increased plasma P(4) and elicited both LH and FSH surges, whereas vehicle-treated controls displayed no rise in P(4) or gonadotropins. This observation confirms that at middle age, female rats no longer respond to the positive-feedback stimulation of E(2) on gonadotropin surges whenever the estrous cyclicity ceases. As PE continued, such a surge-inducing action of E(2) plus P(4) became diminished after 75 days of PE and disappeared thereafter. When caged with males, vehicle-treated early PE rats display a mating-induced increase in P(4) from the adrenal along with small gonadotropin surges. The amplitude of these mating-induced gonadotropin surges was enhanced by supplementation with exogenous P(4) in early PE rats. Our findings indicate that during the early phase of PE, the surge-inducing action of E(2) and P(4) remains intact but deteriorates as PE continues. Thus, a deficiency in P(4) secretion during aging may contribute to the diminished gonadotropin surge response in the hypothalamic-pituitary axis and the subsequent cessation of estrous cyclicity.

The increase in plasma C19Delta5 steroids in subcutaneous abdominal and jugular veins of dairy cattle during pregnancy is unrelated to estrogenic activity

Plasma concentrations of dehydroepiandrosterone (DHEA), 5-androstene-3beta,17beta-diol (AED), and 17beta-estradiol (E2) in dairy cows and heifers and AED binding to uterine cytosolic estrogen receptor (ER) were studied. Plasma samples were collected from the subcutaneous abdominal (SA) and jugular (J) veins of heifers and cows in the non-pregnant state and at 15-45, 90-120, 180-210, and 250-280 days of pregnancy (N = 5-12). Plasma DHEA, AED, and E2 were determined by RIA. DHEA and AED significantly increased (P < 0.001) in heifers and cows throughout pregnancy. The stage of pregnancy significantly (P < 0.001) affected the three steroids in heifers and cows. Plasma DHEA increased throughout pregnancy in both heifers and cows, and in heifers it was significantly greater in SA than in J veins at 90-120 days (P < 0.01). Plasma AED was greater in heifers than in cows in J veins at 90-120 days (P < 0.01) and 180-210 days (P < 0.05), and in SA veins, at 15-45 days (P < 0.01) and 90-120 days (P < 0.05). In heifers, circulating AED showed concentration values significantly greater than those in non-pregnant animals from 90 to 120 days (P < 0.05) and was significantly greater in SA than in J veins at 90-120 days (P < 0.05). In cows, plasma AED was significantly greater than in non-pregnant animals at 250-280 days (P < 0.01). In heifers, plasma E2 was significantly greater in the SA than in the J veins from 180-210 to 250-280 days (P < 0.01). In cows, differences between E2 plasma concentrations in J and SA veins were observed only at 250-280 days of pregnancy. At 250-280 days, in both animal types plasma E2 was significantly greater than in non-pregnant animals (P < 0.001). We suggest that AED originates primarily from the feto-placental unit, while mammary E2 synthesis near term can affect plasma concentrations. Binding data showed that AED is a weak competitor for cytosolic ER (IC50 range: 1.44 x 10(-5) to 3.71 x 10(-5) M). These results suggest that a direct estrogenic activity for AED is unlikely in dairy cattle, and the physiological role of AED needs to be elucidated.

Estrous cyclicity and ovarian follicles in female rats after prenatal exposure to 3,3',4,4',5-pentachlorobiphenyl

Alterations of estrous cyclicity and ovarian follicles following prenatal exposure to PCB126 were examined. Female SD rats were given (i.g.) 25 pg, 2.5, 250 ng and 7.5 microg of PCB126/kg or the vehicle on days 13-19 postconception. Vaginal opening (VO) in the 250 ng and 7.5 microg offspring was significantly delayed. All groups showed irregular estrous cyclicity following VO, but it became normal after a few days. However, the start of normal estrous cyclicity following VO in the 2.5, 250 ng and 7.5 microg groups was significantly delayed. At 30 and 50 days old, the 2.5, 250 ng and 7.5 microg groups showed significantly fewer antral follicles and a higher number of atretic follicles. The 7.5 microg group at 50 days old revealed significantly fewer corpus luteums. In 50-day-old offspring, the 2.5, 250 ng and 7.5 microg groups showed a significant reduction in serum 17beta-estradiol and progesterone levels and significantly higher levels of PCB126 in the fatty tissue compared with the vehicle group. Thus, while the prenatal dose of PCB126 used in this study did not induce malformation of the external genitalia or persistent ovarian disruption, disruption of ovarian function at puberty was found in the 2.5 ng group of pups born to dams exposed to 17.5 ng/kg PCB126. The present study suggests that PCB126, at least in part, exerted direct effects on the ovary as shown by the disruption of estrous cyclicity.

Seasonal changes in neurosteroid concentrations in the amphibian brain and environmental factors regulating their changes

Up to now the regulatory mechanisms, which govern the concentrations of neurosteroids in the brain, are unclear. Seasonal breeders may serve as excellent models to understand physiological changes in neurosteroid levels and their regulatory mechanisms. The present study first investigated immunohistochemically the localization of cytochrome p450 side-chain cleavage enzyme (p450scc) and 3beta-hydroxysteroid dehydrogenase/delta(5)-delta(4)-isomerase (3betaHSD) in the brain of the newt Cynops pyrrhogaster, a seasonally breeding amphibian. Both p450scc- and 3betaHSD-like immunoreactive cells were restricted to the preoptic area. Seasonal changes in neurosteroid concentrations were then examined using adult males. Pregnenolone concentrations in the brain showed marked changes during annual breeding cycle and a maximal level in August, independent of the plasma steroid levels which were all low throughout the year. Progesterone concentrations in the brain, which were lower than pregnenolone levels, also showed peaks in April and August. In contrast, the pregnenolone sulfate level was low and its change was less pronounced. To clarify environmental factors that induce seasonal changes in neurosteroid levels, adult males were further subjected to different photoperiods and ambient temperatures for 5 weeks. Both pregnenolone and progesterone concentrations in the brain were significantly higher in the long day (LD) group than in the short day (SD) group, whereas no significant effects of different ambient temperatures on neurosteroid levels were detected. These results suggest that the newt brain possesses steroidogenic enzymes p450scc and 3betaHSD and exhibits seasonal changes in the pregnenolone and progesterone concentrations. Photoperiod may be a more important environmental factor than temperature for the regulation of neurosteroid levels in the brain.

Effects of aging on hypothalamic-pituitary-adrenal system function in non-human primates

The study was aimed at characterizing the changes in hypothalamic-pituitary-adrenal (HPA) axis function during aging in monkey models (Papio hamadryas and Macaca mulatta). It has been established by specific radioimmunoassay and enzyme immunoassay that basal plasma levels of adrenal androgenes (dehydroepiandrosterone-DHEA, dehydroepiandrosterone sulfate-DHEAS) and the early precursors of steroid hormones (pregnenolone and 17-hydroxypregnenolone) progressively decrease with age in baboons and macaques, while cortisol and 11-desoxycortisol concentrations do not change. The old female rhesus monkeys exhibited a higher cortisol and corticosterone response, but a lower DHEAS response to corticotropin-releasing hormone (CRH) administration then the young monkeys. The aged rhesus monkeys also exhibited a decrease of the adrenal cortex resiliency, that was manifested in the deceleration of the decrease of cortisol concentrations after the peak values had been reached in response to ACTH 1-39 administration. At the same time the ACTH 1-24 depot test revealed no age-related changes in the maximum capacity of monkey adrenals to synthesize and secrete cortisol. The aged monkeys also developed less sensitivity of the HPA axis to dexametasone suppression test. The age-related hormonal changes may play an important role in the age-related involutive processes and in the disorders of the adaptive ability of old organisms.

A reproductive phase-dependent effect of dietary L-tryptophan on pineal gland and gonad of a nocturnal bird, Indian spotted owlet Athene brama

Unlike other temperate owls, Indian spotted owlet Athene brama possesses a well-developed pineal gland that secrets moderate amount of hydroxy- (serotonin) and methoxy- (melatonin) indoles in circulation. However, in this study, we have reported the response of this endocrine gland to exogenous L-Tryptophan (precursor of the above indoles), and also its effect on gonads of this nocturnal bird. During breeding phase or pineal inactive phase (March), oral treatment of L-Trp (0.5 mg/100 g Bwt/day) significantly increased the pineal gland wt and plasma melatonin (MEL) level, while decreased the gonadal wt and plasma sex steroids levels (estradiol and progesterone in female and testosterone in male). Interestingly, during reproductively quiescent phase or pineal active phase (August), similar amount of L-Trp significantly decreased the plasma MEL level, while increased the above sex steroid levels in plasma. Finally, the results show a clear reproductive phase-dependent inverse effect of L-Trp on pineal gland and gonads for both sexes of the spotted owlets, and suggest that the therapeutic use of this amino acid would be a great advantage for controlling the reproduction of these economically important birds.

Ovarian steroidogenic responsiveness to exogenous gonadotropin stimulation in young and middle-aged female rats

Reproductive aging in the female rat is associated with gradual declines in LH secretion and ovarian progesterone (P) production. This study examined whether the influences of aging on P levels reflect decreased ovarian responsiveness to gonadotropin stimulation, as opposed to changes in gonadotropin release. Young and middle-aged regularly cyclic female rats received sodium pentobarbital to block endogenous proestrous luteinizing hormone (LH) surges, followed by administration of various doses of human chorionic gonadotropin (hCG). Similar treatments were performed in middle-aged acyclic persistent-estrous (PE) females. Injection of hCG resulted in equivalent plasma hCG levels in each treatment group. At the lowest hCG dose tested, a significant rise in plasma P levels was observed in middle-aged cyclic rats, but not in young cyclic or middle-aged PE females. This unexpected finding may reflect accelerated follicular development in middle-aged cyclic females, as suggested by a previous study. At the intermediate dose, young and middle-aged cyclic but not PE rats displayed significantly increased P in response to hCG. At the highest dose tested, all three groups of rats displayed increased P levels after hCG stimulation. However, P concentrations were significantly lower in middle-aged PE than regularly cyclic females. Northern and slot blot hybridization analyses revealed that ovarian mRNA levels for cytochrome P450 side-chain cleavage, the rate-limiting enzyme in P synthesis, were markedly reduced in PE rats following hCG stimulation. These findings indicate that ovarian responsiveness to gonadotropin stimulation is impaired in middle-aged PE, but not regularly cyclic rats, and suggest influences of cycle status on the biochemical and molecular mechanisms regulating ovarian steroid production. Furthermore, these findings reveal that attenuated P production in middle-aged proestrous rats is due to attenuated preovulatory LH surges, rather than decreased ovarian sensitivity to LH.

Physical symptoms in premenstrual syndrome are related to plasma progesterone and desoxycorticosterone

Somatic symptoms in the premenstrual syndrome (PMS) may have an etiology separate from that of the mental symptoms. A disturbance in mineralocorticoid action has been discussed, as mineralocorticoids regulate water balance. Desoxycorticosterone (DOC) is interesting, as it has mineralocorticoid effects and is a precursor to the neurosteroid 5 alpha-pregnan-3 alpha,21-diol-20-one (THDOC). THDOC is a steroid with direct benzodiazepine-like effects on the GABA-A receptor in the brain that is metabolized from DOC within the brain and in the periphery. Ten women with PMS having swelling as a major symptom and eight controls were recruited. They marked, on a validated visual-analog scale, three physical symptoms every evening during one menstrual cycle in conjunction with giving blood samples for progesterone and DOC measurements. DOC showed menstrual cycle-linked variation correlating with progesterone. There was no difference in plasma DOC concentrations between patients and controls. The symptoms reached a maximum 1-3 days before the onset of menstruation, with a delay of 3-6 days after the hormone peak. DOC was less strongly correlated with the symptoms than progesterone. These results do not support the hypothesis that DOC is involved in the etiology of physical symptoms in PMS or that physical and mental symptoms have separate etiologies.

Castration increases and androgens decrease nitric oxide synthase activity in the brain: physiologic implications

Sex differences in nitric oxide synthase (NOS) activity in different regions of the rat brain and effects of testosterone and dihydrotestosterone (DHT) treatment in orchidectomized animals were investigated. Regional but no sex differences in NOS activity were detected in gonadectomized animals. Orchidectomy significantly increased NOS activity in the hypothalamus, "amygdala," and cerebellum but not in the cortex. In the hypothalamus, the increase in NOS activity after castration and its reversal by androgen treatment was mimicked by changes in neuronal NOS mRNA level. In contrast, androgen receptor (AR) mRNA level in the hypothalamus was slightly reduced by castration and increased by treatment with DHT. Again in the hypothalamus, the increase in NOS activity in castrated rats was accompanied by an increase in the number of neuronal NOS+ cells determined immunohistochemically, whereas androgen treatment prevented this increase. The changes in NOS+ neurons correlated with the changes in the number of AR+ cells to a degree. Overlap of AR in NOS+ cells was not present in the regions of the hypothalamus analyzed. These results indicate that testosterone or, most likely, its metabolite DHT down-regulates NOS activity, mRNA expression or stabilization, and the number of neuronal NOS+ neurons.

Castration increases and androgens decrease nitric oxide synthase activity in the brain: physiologic implications

Sex differences in nitric oxide synthase (NOS) activity in different regions of the rat brain and effects of testosterone and dihydrotestosterone (DHT) treatment in orchidectomized animals were investigated. Regional but no sex differences in NOS activity were detected in gonadectomized animals. Orchidectomy significantly increased NOS activity in the hypothalamus, "amygdala," and cerebellum but not in the cortex. In the hypothalamus, the increase in NOS activity after castration and its reversal by androgen treatment was mimicked by changes in neuronal NOS mRNA level. In contrast, androgen receptor (AR) mRNA level in the hypothalamus was slightly reduced by castration and increased by treatment with DHT. Again in the hypothalamus, the increase in NOS activity in castrated rats was accompanied by an increase in the number of neuronal NOS+ cells determined immunohistochemically, whereas androgen treatment prevented this increase. The changes in NOS+ neurons correlated with the changes in the number of AR+ cells to a degree. Overlap of AR in NOS+ cells was not present in the regions of the hypothalamus analyzed. These results indicate that testosterone or, most likely, its metabolite DHT down-regulates NOS activity, mRNA expression or stabilization, and the number of neuronal NOS+ neurons.

Estradiol inhibits leukocyte adhesion and transendothelial migration in rabbits in vivo : possible mechanisms for gender differences in atherosclerosis

The mechanism by which estrogens protect against atherosclerosis is not known. We evaluated in vivo whether there is a gender difference in monocyte adhesion and subendothelial migration in hypercholesterolemic rabbits and whether any gender differences observed are due to estradiol. Monocyte adhesion and subendothelial migration were assessed in a blinded fashion by analyzing a standardized segment of aorta using a scanning electron microscope. We also assessed whether estradiol modulates induction of vascular cell adhesion molecule-1 (VCAM-1) protein using Western blot and flow cytometric analyses. We observed that male rabbits develop more monocyte adhesion and subendothelial migration than do female rabbits during hypercholesterolemia. We also observed that oophorectomized rabbits given physiological estradiol supplementation demonstrate fewer adherent and subendothelial monocytes than do oophorectomized rabbits given placebo. VCAM-1 protein expression was increased in aortae obtained from hypercholesterolemic, oophorectomized animals supplemented with placebo, and this increase was attenuated by estradiol. Finally, in cultured rabbit aortic endothelial cells stimulated with lysophosphatidylcholine, we observed an increase in VCAM-1 protein that was inhibited in a concentration-dependent fashion by estradiol. We have demonstrated in vivo that there is a gender difference in monocyte adhesion to endothelial cells and transendothelial migration after hypercholesterolemia and that this gender difference is due in part to estradiol. Our results also suggest that estradiol inhibits monocyte adhesion by inhibiting expression of VCAM-1.

Expression and activity of 3beta-hydroxysteroid dehydrogenase/Delta5-Delta4-isomerase in different regions of the avian brain

Recently, we have demonstrated, using biochemical and immunochemical methods, that the quail brain possesses the cholesterol side-chain cleavage enzyme (cytochrome P450scc) and produces pregnenolone and its sulfate ester. To clarify progesterone biosynthesis in the avian brain, therefore, we examined the expression of messenger RNA (mRNA) encoding for the enzyme 3beta-hydroxysteroid dehydrogenase/Delta5-Delta4-isomerase (3beta-HSD) and its enzymatic activity using the quail. RT-PCR analysis together with Southern hybridization indicated the expression of 3beta-HSD mRNA in the brain of sexually mature birds but with no clear-cut sex difference. Employing biochemical techniques combined with HPLC analysis, the conversion of pregnenolone to progesterone was found in brain slices of mature males. Progesterone biosynthesis was increased in a time dependent manner and completely abolished by trilostane, a specific inhibitor of 3beta-HSD. The enzymatic activity of 3beta-HSD was greatest in the cerebrum and lowest in the mesencephalon. A specific RIA indicated that progesterone concentrations in the different brain regions closely followed the level of 3beta-HSD activity. High levels of progesterone concentration were observed in the diencephalon and cerebrum with lowest values in the mesencephalon. Progesterone levels in the brain regions were significantly higher than those in the plasma. These results suggest that the avian brain possesses not only cytochrome P450scc but also 3beta-HSD and produces progesterone. It is also indicated that progesterone biosynthesis in the avian brain may be region-dependent.

Expression and activity of 3beta-hydroxysteroid dehydrogenase/delta5-delta4-isomerase in the rat Purkinje neuron during neonatal life

Recently, we demonstrated that cytochrome P450 side-chain cleavage enzyme (P450scc) occurs in the rat cerebellar Purkinje cell after differentiation and remains during neonatal development and into adulthood. 3Beta-hydroxysteroid dehydrogenase/delta5-delta4-isomerase (3betaHSD) is also an essential enzyme for progesterone biosynthesis not only in peripheral steroidogenic glands but also in the nervous system. In the present study, therefore, the expression of 3betaHSD in the rat cerebellum was investigated during neonatal development and in the adult. RT-PCR analysis showed that the expression of 3betaHSD messenger RNA (mRNA) in the cerebellum was higher at 7-14 days of age than at other times. Biochemical studies together with HPLC analysis revealed that cerebellar slices at 10 days of age converted pregnenolone to progesterone, suggesting enzymatic activity of 3betaHSD. This conversion was significantly reduced by trilostane, a specific inhibitor of 3betaHSD. A specific RIA indicated that progesterone concentrations in the cerebellum were higher at 3 and 10 days of age than at 60 days of age. The progesterone level in the cerebellum was significantly higher than that in plasma at 10 days of age. In contrast, the concentrations in both cerebellum and plasma at 3 and 60 days of age were similar. In the present study, the site of 3betaHSD mRNA expression in the cerebellum was further examined in neonatal and adult rats using in situ hybridization. The cerebellar expression of 3betaHSD mRNA was obscure at 3 days of age, whereas intense expression occurred in Purkinje cells and external granule cells throughout the cerebellum at 10 days of age. 3BetaHSD mRNA was also expressed in Purkinje cells and granule cells at 60 days of age, but a restricted expression was observed along the cerebellar meninges. These results suggest that the steroidogenic enzyme 3betaHSD as well as P450scc are expressed at least in the cerebellar Purkinje cell. The expression of 3betaHSD, however, may increase for a limited period around 10 days of age, unlike P450scc.

Estradiol suppresses MCP-1 expression In vivo : implications for atherosclerosis

The mechanisms by which 17beta-estradiol retards atherogenesis are not known. The adhesion of monocytes to endothelial cells followed by the migration of monocytes into the artery wall are key cellular events that occur throughout the entire atherogenic process and may be responsive to estradiol. Monocyte chemoattractant protein-1 (MCP-1), a chemokine that is expressed in atherosclerotic lesions, is thought to play a major role in stimulating the migration of blood monocytes into developing atherosclerotic lesions. We therefore assessed the effects of estradiol in vivo on MCP-1 protein and mRNA expression in the descending thoracic aorta of rabbits fed a cholesterol-enriched (0.5%) diet for 6 weeks and in animals fed normal chow. MCP-1 protein was quantified by Western blot analysis and monocyte chemotaxis bioassay, and reverse transcription-polymerase chain reaction was used to ascertain the level of MCP-1 mRNA expression. We observed that in both ovary-intact and ovariectomized (OVX) animals, MCP-1 protein and mRNA expression were significantly increased by 6 weeks in animals fed a high-cholesterol diet. The cholesterol-induced increase in MCP-1 protein and mRNA expression was significantly attenuated in OVX rabbits supplemented with estradiol pellets (1.5- and 10.0-mg 60-day-release pellets), which yielded a range of estradiol concentrations encompassing the physiological levels. MCP-1 protein and mRNA expression were increased in normocholesterolemic OVX rabbits compared with normocholesterolemic ovary-intact animals, and this increase was prevented in OVX animals supplemented with estradiol pellets. Our observations indicate that both basal and hypercholesterolemia-induced increases in MCP-1 protein are modulated by physiological concentrations of estradiol.

Purified neem (Azadirachta indica) seed extracts (Praneem) abrogate pregnancy in primates

The use of neem (Azadirachta indica) seed extracts (Praneem) given orally for abrogation of pregnancy in subhuman primates is described. Oral administration of Praneem was initiated after confirmation of pregnancy using Leydig cell bioassay estimating rising levels of chorionic gonadotropin (CG) in the blood from day 25 onwards of the cycle and continued for six days. Termination of pregnancy was observed with the appearance of blood in the vaginal smears and decline in CG and progesterone. Pregnancy continued in the control animals treated with peanut oil at the same dose. The effect was observed in both baboons and bonnet monkeys. The treatment was well tolerated; blood chemistry and liver function tests had normal values. The animals regained their normal cyclicity in the cycles subsequent to Praneem treatment.

Estradiol and testosterone in specific regions of the human female brain in different endocrine states

Post-mortem concentrations of estradiol and testosterone were measured in 17 brain areas, serum and fat in 6 fertile and 5 postmenopausal women. Steroid concentrations were measured with radioimmunoassay after extraction of brain tissue with ethanol and purification with celite chromatography. There were regional differences in brain concentrations of both steroids. The highest levels of estradiol and testosterone were noted in the hypothalamus, preoptic area and substantia nigra. These findings may assist in the interpretation of functional animal studies where the hypothalamus-preoptic area and the nigrostriatal dopamine system have proved to be target areas for estradiol. When compared to postmenopausal women, estradiol concentrations were significantly higher in the brains of fertile women, which indicates that peripheral serum levels of estradiol are reflected in the brain. This study has yielded information about steroid levels in different endocrine states and could provide a frame of reference for studies of estradiol and testosterone mediated effects on the central nervous system.

Avian neurosteroids. I. Pregnenolone biosynthesis in the quail brain

The present study was carried out to determine steroid biosynthesis from cholesterol in the brain of adult male Japanese quails. As an initial step of the experiments, the concentrations of pregnenolone, dehydroepiandrosterone and their sulfate esters in the brain and plasma extracts were measured by specific radioimmunoassays (RIAs). To exclude the possibility that these steroids in the brain are derived from peripheral steroidogenic glands, hypophysectomized and sham-operated birds were used in this experiment. The pregnenolone concentration was much larger in the brain than in the plasma in these two groups. Hypophysectomy led to decreases in the plasma and brain pregnenolone concentrations, but the change in the brain was less pronounced than that in the plasma. Although pregnenolone sulfate ester, dehydroepiandrosterone and its sulfate ester were also detected in brain extracts, those levels were low in both hypophysectomized and sham-operated birds. The biochemical demonstration of cholesterol metabolism was further conducted in intact mitochondria. When mitochondrial fractions obtained from the whole brain were incubated with cholesterol at 37 degrees C, the pregnenolone level in mitochondria increased as a function of incubation time. Finally, Western immunoblot analysis using a purified IgG with polyclonal antibodies against the purified bovine adrenal cytochrome P450scc was performed after SDS-gel electrophoresis of homogenates of the hypothalamus and preoptic area. A protein recognized the antibody as a band of electrophoretic mobility in the proximity of reference bovine P450scc. These results suggest that the brain produces pregnenolone from cholesterol in adult male Japanese quails. Most accumulation of pregnenolone in the brain may be independent of the peripheral endocrine gland system.

Temporal regulation by estrogen of beta-preprotachykinin mRNA expression in the rat ventromedial nucleus of the hypothalamus

In the rat, reproduction and sexual behavior are controlled by the gonadal steroid regulation of synaptic interactions within the sexually dimorphic limbic-hypothalamic system. The effects of estrogen on the ventromedial nucleus of the hypothalamus, one nucleus within the circuit, are central to the modulation of this behavior. Involvement of the neuropeptide substance P, a member of the tachykinin family of neuropeptides, has been implicated in the regulation of both lordosis behavior and gonadotropin release. However, previous studies have provided conflicting evidence as to whether levels of substance P in the ventromedial nucleus of the hypothalamus are modulated by circulating estrogens. To study this question further, in situ hybridization histochemistry was used to examine levels of beta-preprotachykinin mRNA, which encodes substance P and other tachykinins, in the ventrolateral subdivision of the ventromedial hypothalamus at 10 consecutive timepoints over a 4 day period subsequent to an acute administration of estrogen. Following estrogen treatment, beta-preprotachykinin mRNA expression was increased in cells of the ventrolateral portion of the ventromedial nucleus of the hypothalamus which constitutively express beta-preprotachykinin mRNA; however, there were no statistically significant changes in the number of cells that express detectable levels of beta-preprotachykinin mRNA in the ventrolateral portion of the ventromedial nucleus. Estrogen treatment produced two peaks of beta-preprotachykinin mRNA expression, the first at 2 h and the second at 48 h after the injection of estrogen. These data indicate that estrogen has both rapid and prolonged effects on beta-preprotachykinin mRNA levels, suggesting that estrogen may affect different cellular mechanisms relevant to the induction of beta-preprotachykinin mRNA expression.

Termination of early pregnancy in the rat, rabbit, and hamster with RU 486 and anordrin

The effectiveness of oral RU 486 and anordrin given alone and in combination for terminating early pregnancy was tested in the rat, rabbit, and hamster. In the rat and rabbit, the combination of RU 486 and anordrin is more effective in terminating pregnancy than either of the two compounds used alone. A non-effective dose of RU 486 combined with a non-effective or a sub-effective dose of anordrin, or a low effective dose of RU 486 in combination with a non-effective dose of anordrin, exerted additive or synergistic effects resulting in resorption of embryos and termination of pregnancy in rats and rabbits. The serum progesterone as well as estradiol concentrations were significantly suppressed by these combinations when pregnancy was terminated. In the hamster, however, RU 486 was not effective in interrupting early pregnancy, even at a 4-fold higher dose than was effective in the rat, due to the fact that RU 486 does not bind to the progestin receptor in this species. Unexpectedly, there were also no effects of anordrin on pregnancy termination in the hamster even at high doses. It is concluded that in rat and rabbit, the synergistic action between RU 486 and anordrin not only greatly enhances efficacy in terminating pregnancy but also reduces substantially the doses required to produce this effect.

Potentiating effect of epostane on pregnancy terminating activity of RU 486 in the rat

The effectiveness of a combination of RU 486, an antiprogestin, and epostane, a 3 beta-hydroxysteroid dehydrogenase inhibitor, for termination of pregnancy in female rats was determined. Epostane administered at doses ranging from 8 to 48 mg/Kg/day on days 7, 8, and 9 of pregnancy did not influence the progress of the pregnancy. RU 486 in doses of 1, 2, and 4 mg/Kg/day terminated pregnancy in 0, 40, and 100% of rats, respectively. The combination of epostane (48 mg/Kg/day) plus RU 486 (1 and 2 mg/Kg/day) terminated pregnancy with complete resorption of fetuses in all treated animals. Unexpectedly, the drug combination that terminated pregnancy used a dose of epostane that was not highly effective in lowering serum progesterone levels when epostane was administered alone. Thus, in the rat, the synergistic action of epostane plus RU 486 may not be dependent upon reduced progesterone secretion plus receptor blockage as anticipated. The present results suggest that the combination of epostane plus RU 486 is effective for pregnancy termination.

Basal release of nitric oxide from aortic rings is greater in female rabbits than in male rabbits: implications for atherosclerosis

Estradiol is known to exert a protective effect against the development of atherosclerosis, but the mechanism of this hormonal action is unknown. One of the early events in the development of atherosclerosis is the adhesion of macrophages to endothelial cells, and nitric oxide (NO) inhibits this process. We show that basal release of NO is greater with endothelium-intact aortic rings from female rabbits than those from males. Oophorectomy diminishes both circulating estradiol concentration and basal release of NO to levels seen in male rabbits. These data establish that basal NO release from endothelium-intact aortic rings depends on circulating estradiol concentration and offer an explanation for the protective effect of estradiol against the development of atherosclerosis.

Prenatal ethanol and the prepubertal sexually dimorphic nucleus of the preoptic area

The volume of the sexually dimorphic nucleus of the preoptic area of the hypothalamus (SDN-POA) was determined in 14-31-day-old male and female rats whose mothers received a liquid diet containing 5% w/v ethanol from day 8 of gestation to parturition. Pair-fed dams received as a nutritional control an equal volume of an isocaloric liquid diet with maltose-dextrin in place of ethanol. Normal controls had laboratory rat chow and water available ad lib. The SDN-POA volume of ethanol-exposed males was significantly reduced compared to the pair-fed and normal males, and became indistinguishable from the SDN-POA volumes of the pair-fed and normal females. Ethanol-treated females also had a markedly reduced SDN-POA volume compared to the pair-fed and normal females. Our findings indicate that the SDN-POA of prepubertal rats of both sexes is sensitive to the effects of in utero ethanol exposure. While plasma testosterone, progesterone and estradiol titers, which we measured in fetuses on gestation day 22, were differentially affected by maternal ethanol consumption, the alterations by themselves cannot adequately explain the effects of prenatal ethanol exposure on the developing SDN-POA.

Sex-related incidence of tubular metaplasia in Bowman's capsule of aging rats

Although chronic progressive nephropathy and proteinuria are well-known to affect old laboratory rats, the occurrence of tubular metaplasia of Bowman's capsule (TM) in aging rats has received little attention. We report here that old (24-26 months) male, but not female Sprague-Dawley rats show a high incidence of TM which is significantly (P less than 0.01) correlated with the levels of glomerular sclerosis and intracellular deposits of iron in the tubular epithelium. The incidence of these changes was not correlated with serum testosterone levels, which showed a significant age-related reduction in males. The reported findings suggest that the aging male Sprague-Dawley rat is a useful animal model to investigate the pathogenesis of TM and related morphologic changes in hematuric humans.

Gonadal function in aging rats and its relation to pituitary and mammary pathology

In the female rat, aging is characterized by a high incidence of prolactin (Prl)-secreting pituitary adenomas and mammary tumors. In contrast to this, old males show only a moderate to low incidence of pituitary and mammary pathology. Since gonadal steroids and Prl are thought to be key factors in the genesis of the above neoplastic pathologies, it was of interest to compare the serum levels of progesterone (P), estradiol (E2), testosterone (T) and Prl with the incidence of pituitary and mammary tumors in aging male and female rats. Young (3-4-month; YF), old (25-month; OF) and senescent (33-35-month; SF) female and young (3-4-month; YM) and old (24-26-month; OM) male Sprague-Dawley rats were killed by decapitation and their pituitaries weighed. Serum sex steroids and Prl were measured by RIA. The average life span of females but not males was markedly extended by systematic removal of mammary tumors. Females showed a rising incidence of mammary tumors after 14 months of age. In males, this pathology which began to appear at 16 months, had a much lower incidence than in females at all ages. Serum levels of E2 were (means +/- S.E.M.) 22.0 +/- 1.6; 18.9 +/- 0.8; 32.9 +/- 2.5; 37.3 +/- 2.0 and 32.2 +/- 3.0 pg/ml for YM, OM, YF, OF and SF, respectively. Serum P was 1.4 +/- 0.3; 1.6 +/- 0.2; 10.4 +/- 2.2; 9.7 +/- 3.3 and 6.8 +/- 0.8 ng/ml for YM, OM, YF, OF and SF, respectively. Serum T was 1578.9 +/- 188.7; 807.6 +/- 103.0; 197.5 +/- 11.8; 223.7 +/- 25.5 and 176.9 +/- 20.7 pg/ml for YM, OM, YF, OF and SF, respectively. Finally, serum Prl was 14.9 +/- 1.7; 21.9 +/- 4.0; 15.9 +/- 1.4; 52.4 +/- 9.4 and 170.8 +/- 31.1 ng/ml for YM, OM, YF, OF and SF, respectively. A strong correlation was found between serum Prl and anterior pituitary weight in OM, OF and SF, but not between serum Prl and sex steroid levels or sex steroid ratios. We conclude that, although the sex-related differences in mammary and pituitary tumor incidence during aging in rats can be partially accounted for by the different serum profiles of Prl and gonadal steroids in each sex, sex-associated differences in target tissue susceptibility should also be considered as an important determinant of the level of tumor incidence.

Sex steroids in human brain tumors and breast cancer

The concentrations of three sex steroids, estradiol, progesterone and testosterone, were analyzed by radioimmunoassay after celite chromatography in brain tumor and breast cancer tissues. The concentrations in malignant gliomas and breast cancers showed interindividual variations, especially evident with regard to estradiol. High estradiol concentrations were recorded in two patients with malignant astrocytoma. The concentrations of 1.00 pg/mg and 3.32 pg/mg were 10 to 30 times as high as in normal female brain. In five of ten astrocytomas the estradiol concentration was higher than the lowest breast cancer value. The distribution of progesterone seemed more even, and the level was significantly lower in brain tumors and breast cancers as compared with female brain, perhaps indicating an increased metabolism. Testosterone levels were somewhat higher in brain tumors, as compared with breast cancers, but not different from values in brain tissue. There were no significant age or sex correlation or differences in the concentrations of steroids in the brain tumors. The results suggest that manipulation of sex steroid metabolism in malignant brain tumors can be of beneficial therapeutic value as has been shown for breast cancer and prostatic carcinoma.

Functional morphology of testis and its excurrent ducts in rats immunized with synthetic luteinizing hormone releasing hormone conjugated to tetanus toxoid

The effects of active immunization against luteinizing hormone releasing hormone (LHRH) on the testis and its excurrent ducts in rats were studied using a synthetic LHRH peptide conjugated to tetanus toxoid (TT), with or without an adjuvant. The study demonstrated that LHRH-TT given alone did not elicit an appreciable immune response and that its immunogenicity could be enhanced by administration with an adjuvant, such as species-specific IgG or SPLPS. The anti-LHRH antibody response showed a corresponding regressive effect on the morphology of the testis and its excurrent ducts. The functional involution of the testis was reflected in the form of a block in spermatogenesis and the lowering of testosterone production; the basic structural organization of the testicular components was, however, maintained. Epididymal ducts displayed rather drastic atrophic changes, indicating that prolonged immunization may result in irreversible damage to the excurrent ducts and could, therefore, adversely affect the restoration of fertility even after the return of testicular function following decline in the immune response against LHRH. This could be an important consideration if LHRH immunization is to be used for male contraception.

Pharmacokinetics and pharmacodynamics of a new long-acting androgen ester: maintenance of physiological androgen levels for 4 months after a single injection

The pharmacokinetics and pharmacodynamics of testosterone trans-4-n-butylcyclohexyl carboxylate (Code name: 20 Aet-1), a new long-acting androgen ester, were evaluated in castrated adult rhesus monkeys and compared with those of testosterone enanthate (TE). A single intramuscular injection of 40 mg of 20 Aet-1 returned serum testosterone (T) to within or close to the diurnal physiological range for 80-136 days. In contrast, a similar dose of TE increased serum T to supraphysiological levels and the response evoked was of short duration. The ratio of T to dihydrotestosterone (T/DHT) ratio in monkeys treated with 20 Aet-1 was comparable to that found in control animals while in TE-treated animals, it was highly elevated. Serum estradiol (E2) elevation by 20 Aet-1 was also of smaller magnitude compared to TE. 20-Aet-1 suppressed LH levels from day 5 until day 115. The levels of LH on day 115 were 45.8% lower compared to the levels on day 13 post-castration. TE suppressed LH levels from day 1-7 post-injection. The values on day 7 were 76.6% lower compared to values on day 13 post-castration. Thus, TE-induced suppression of LH was of shorter duration, but of greater magnitude compared to the effect caused by 20 Aet-1. Similarly, FSH was suppressed for a longer duration (days 21-74) by 20 Aet-1 than by TE. The results indicate that the new testosterone ester has highly favourable pharmacokinetic properties and may prove to be the androgen of choice for supplementation therapy in contraceptive regimens.

Effect of dihydrotestosterone on testicular and accessory gland function in male rhesus monkeys

Pituitary, testicular and accessory gland functions were assessed at intervals of 10-20 days in adult male rhesus monkeys given 10, 100 or 1000 micrograms dihydrotestosterone (DHT). Circulating levels of LH and testosterone were suppressed. Ejaculated spermatozoa showed morphological abnormalities and decrease in motility but sperm counts were unaffected. Seminal fructose was decreased in animals receiving DHT. Sexual behaviour was maintained in these animals.

Endometrial and vaginal response to three different oestrogen preparations administered by the transdermal and oral routes

In a randomized, cross-over study endometrial and vaginal response to transdermal 17 beta-oestradiol (TTS-oestradiol 50 micrograms) and two forms of oral oestrogen replacement therapy (conjugated oestrogens 1.25 mg and oestradiol valerate 2 mg) were studied in 13 peri-menopausal and post-menopausal women. Five (5) of the women exhibited periodic ovarian function as evidenced by peripheral oestradiol and progesterone levels and were considered to be peri-menopausal. In the post-menopausal group of 8 women the bleeding pattern was more regular than among the peri-menopausal women. In the case of the post-menopausal group the number of days on which spotting and bleeding occurred was significantly lower during the administration of TTS-oestradiol than during treatment with conjugated oestrogens. This finding was paralleled by a significantly higher karyopyknotic index in the vaginal epithelium and significantly increased deoxyribonucleic acid (DNA) synthesis in the endometrial cells during treatment with equine oestrogens. No significant difference was seen in these indices when the effect of TTS-oestradiol was compared with that of oestradiol valerate. The study results in the post-menopausal group suggested a relationship between the intensity of the oestrogen treatment and not only the proliferation and maturation of the oestrogen target-organ cells but also the number of days on which bleeding occurred. It was concluded that a clear distinction needs to be made between peri-menopausal and post-menopausal women. In the present study the irregular ovarian activity among the peri-menopausal subjects precluded an unbiased assessment of the exogenous oestrogens. It is also likely that exogenous oestrogens exert a cumulative action with oestrogen secreted endogenously, interfere with the physiological events at the target organ level and induce uncontrollable endometrial bleeding. The complete cessation of ovarian activity may therefore have to be established before exogenous oestrogens are administered to climacteric patients.

Endocrine, seminal and peripheral effects of depot medroxyprogesterone acetate and testosterone enanthate in men

Depot medroxyprogesterone acetate (D-MPA, 250 mg) and testosterone enanthate (TE, 200 mg) were administered twice with a 4-week interval to nine healthy men, and the levels in blood of steroids, gonadotrophins, lipoproteins, sex hormone binding globulin (SHBG) and prostaglandins (PGs) were measured, as well as steroid levels in semen and the sperm count and motility. The hormones analysed were: MPA, testosterone, androstenedione (A), dihydrotestosterone (DHT), oestradiol (E2), cortisol (C), luteinizing hormone (LH), follicle stimulating hormone (FSH) and the sulphoconjugated forms (-S) of testosterone, DHT, pregnenolone (5-P) and dehydroepiandrosterone (DHEA). Peak values of MPA (10.2 +/- 4.6 nmol/l) and testosterone (28.0 +/- 10.0) were found in the first blood samples 2 days after each injection. Thereafter the levels of MPA decreased gradually and reached the limit of detection 18-20 weeks after the second injection. Blood levels of testosterone fell sharply from the peak values and were grossly subnormal 2 weeks after each injection; levels did not return to pretreatment values during 24 weeks of follow-up. The pattern of change of DHT, A, E2 and sulphonated androgens was similar to that of testosterone. These data suggest that D-MPA and TE are absorbed at similar rates, and that the TE is metabolized rapidly. The subsequent reduction in the levels of A, testosterone-S and DHT-S was less marked and reached pretreatment values earlier than did the testosterone levels. No obvious changes were found in the levels of C, 5-P-S and DHEA-S or in the seminal plasma levels of the various steroids studied. The blood levels of LH and FSH fell precipitously 2 days after the first injection, then started to increase 4 weeks after the second injection to reach pretreatment values 12 weeks later. Of the lipoproteins studied only the levels of HDL-cholesterol and SHBG were found suppressed after treatment. Severe oligozoospermia and the complete absence of progressively motile sperm, in at least one semen sample, was observed in all subjects at 3-7 and at 5-16 weeks, respectively, after the last injection, suggesting that the men were infertile for at least 1 month after treatment. A spurious increase in the PG content of semen was also observed. In spite of the low blood testosterone levels, no subject reported changes in sexual behaviour or other signs of anabolic imbalance during or after the study. However, the increase in levels of E2 in some individuals should be kept in mind as a possible cause of side-effects.(ABSTRACT TRUNCATED AT 400 WORDS)

Simultaneous radioimmunoassay of progesterone, androst-4-enedione, pregnenolone, dehydroepiandrosterone and 17-hydroxyprogesterone in specific regions of human brain

Simultaneous determination of progesterone, androst-4-enedione, pregnenolone, dehydroepiandrosterone (DHEA) and 17-hydroxyprogesterone has been developed for human cerebral tissue. Before immunoassay, steroids were separated on a Celite column with propylene glycol as stationary phase with hexane containing increasing proportions of dichloromethane as mobile phase. This system allowed separation of steroids of similar polarity, especially of pregnenolone and progesterone. The brain regions studied cortex (prefrontal, parietal and temporal), cerebellum and corpus callosum, were obtained after autopsy from 9 women and 1 man between 76 and 93 years of age. Steroids were found in all regions. The overall concentrations expressed in nmol/kg of tissue were: 10.1, 7.6, 120.7, 19.6 and 10.4 respectively, for progesterone, androst-4-enedione, pregnenolone, dehydroepiandrosterone and 17-hydroxyprogesterone, corresponding to 7.3, 4.9, 74, 6.5 and 9.2 times the plasma levels. These very high concentrations, not previously described in human brain tissue, pose the question of the existence of local biosynthetic pathways independent of the peripheral endocrine gland system as well as that of progressive accumulation of steroids over a lifetime. Concentrations of each steroid in each subject varied little among the various brain regions studied, but there was much variation among the subjects with respect to the concentrations of a given steroid.

Plasma levels of antiprogestin RU 486 following oral administration to non-pregnant and early pregnant women

RU 486 is a synthetic steroid which acts as an antiprogestin at the receptor level. The clinical usefulness of the compound for menstrual regulation and termination of early pregnancy is currently being evaluated. The aim of the present study was to determine the plasma levels of RU 486 following the oral administration of the compound to 42 pregnant and 10 non-pregnant women. The levels of RU 486 were measured by a radioimmunoassay method which uses chromatography on Sephadex LH 20 columns. The identity of the compound assayed as RU 486 was confirmed, but the presence of small amounts of two highly cross-reacting metabolites (monodemethyl and didemethyl RU 486) in the analyzed fractions could not be excluded. Following the ingestion of a single tablet containing 25 and 50 mg of the compound, a peak plasma value of approximately 3.5 to 4.0 mumol/l in both the pregnant and non-pregnant subjects was reached one to two hours later. The half-lives of elimination were about 20 hours in both the pregnant and the non-pregnant women. Following the repeated oral administration of 50, 100 or 200 mg of RU 486 daily for four days, maximum plasma levels of 2.9, 4.5 and 5.4 mumol/l, respectively, were found. Thus, the increase in plasma levels was not directly proportional to the increase in the dose. No accumulation of RU 486 in the plasma was found, even when the duration of treatment was prolonged to six days. The data partly explain the reported lack of relation between ingested dose and frequency of induced abortion and they may be useful for designing future studies on the use of compound to prevent implantation, induce menstruation or terminate an early pregnancy.

Comparison between pre- and postovulatory distributions of oestradiol and progesterone in the brain of the PMSG-treated rat

The pre- and postovulatory levels of oestradiol and progesterone were measured in seven brain areas, peripheral fat, muscle tissue and blood plasma in 49 immature female rats which had been given an injection of 4 IU PMSG (Pregnant Mare Serum Gonadotropin) on the 25th day of life. We observed a uniform decline in oestradiol concentration in all the areas of the postovulatory rat. The highest mean concentrations of oestradiol pre- and postovulatory were found in the hypothalamus and the striatum (260 +/- 26, 110 +/- 11, 200 +/- 39 and 75 +/- 13 pg g-1, respectively). The levels of progesterone showed variable increases in all the areas postovulatory. The highest postovulatory concentration was found in the cerebral cortex (29 +/- 2.0 ng g-1) where the increase was six-fold greater than the increases in any of the other areas compared to preovulatory values. The hypothalamus contained high progesterone levels at both times (3.5 +/- 0.68 ng g-1 and 27 +/- 5.2 ng g-1) compared to other areas. We conclude that the female rat brain exhibits differences in the distribution of oestradiol and progesterone both pre- and postovulatory. Since the levels in different brain areas to a large extent varied independently we suggest different uptake mechanisms and/or different binding capacities in various regions of the rat brain.

Blood and tissue steroid levels and their interrelationship in men with pathological conditions of the reproductive organs

We have investigated the interrelationship of the levels of 10 steroids in peripheral venous, spermatic arterial and spermatic venous blood, and in tissue specimens from the epididymis, vas deferens and testis from 8 patients who underwent orchidectomy for pathological conditions of the reproductive organs. The steroids analyzed by radioimmunoassay were: pregnenolone (5-P), dehydroepiandrosterone (DHEA), 17-hydroxyprogesterone (17-OH-P), androstenedione (A), testosterone (T), dihydrotestosterone (DHT) and the sulpho-conjugated forms (-S) of 5-P, DHEA, T and DHT. The quantitatively major steroids in peripheral venous blood were, in order of magnitude, DHEA-S, 5-P-S, DHT-S, T-S and T. No difference was observed between the levels of any of the steroids measured in peripheral venous and spermatic arterial blood. With the exception of DHEA-S and DHT-S, the levels of all steroids in spermatic venous blood were substantially higher than in peripheral venous blood (P less than 0.001). No correlation was found between steroid levels in spermatic venous and peripheral venous blood. Steroid concentrations in tissue from the epididymis, vas deferens and testis were markedly higher than in peripheral venous blood (P less than 0.01 to P less than 0.001), except for the levels of DHEA-S which were about equal in the various blood and tissue specimens. Tissue to blood ratios varied from approximately 2.0 to 500 according to the steroid in question. The peripheral blood levels of 5-P-S, DHEA-S and DHT-S were substantially higher than respective unconjugated steroid levels (P less than 0.001); the ratios (sulpho-conjugated to unconjugated) were approximately 17, 215 and 30, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of dopaminergic drugs on plasma levels of steroid hormones in conscious dogs

Progesterone, cortisol and testosterone levels were measured by radioimmunoassay in peripheral venous blood of conscious dogs. I.v. injections of the dopamine receptor agonists apomorphine (0.05 mg/kg) and bromocriptine (0.1 mg/kg) increased progesterone levels (and cortisol levels, as previously shown) in dogs of both sexes. The response to apomorphine was abolished by pretreatments with peripheral dopamine receptor antagonists (domperidone and halopemide). Progesterone and cortisol responses to the dopamine receptor agonists were parallel, but the ratio of concentration was 1/100. Testosterone levels were not modified. These results suggest that the dopamine receptor agonists stimulate progesterone release from the adrenal glands at a site functionally accessible to the peripheral dopamine receptor antagonists. In addition, the neuroleptic haloperidol (0.1 mg/kg) was shown to cause long lasting increases of progesterone levels.

Relationships between serum FSH level and the size of testis in azoospermic patients

Sixty-eight out of 700 patients proved to be azoospermic at our Andrology Clinic between 1981 and 1983. According to the serum FSH level and testis size, three main diagnostic groups were established: 1. patients with occlusion but testis size and FSH level normal; 2. patients with smaller testis size and increased FSH level and primary spermatogenetic disorder; 3. non-palpable testis and increased serum FSH level referring also to testicular disorder. No correlations were found between serum LH and testosterone levels and testicular volume.

The prediction and/or detection of ovulation by means of urinary steroid assays

Twenty normally menstruating women volunteered for a study in which plasma samples were collected daily during an entire menstrual cycle. On the same days, samples of morning urine were also collected, as well as random samples of urine voided at the visit to the Outpatient Clinic. Progesterone (P), estradiol (E2) and lutropin (LH) were assayed in plasma, and pregnanediol-3-glucuronide (PdG), estrone-glucuronide (E1G), estriol-16-glucuronide (E3G), P, and E2 were measured in urine using radioimmunoassays. Progesterone in urine was assayed both with and without preceding chromatography. All urinary glucuronides and progesterone exhibited cyclic patterns similar to those of E2 or P in plasma. Seven-fold increases from early follicular to luteal phase values (for PdG and urinary P; the latter both with and without chromatography), or to peak levels (for E1G and E3G) were observed. The difference between the baseline and peak levels was less distinct (approximately 5-fold) for E2 in urine. The day-to-day coefficient of variation of early follicular phase values decreased from 40% to 25% by calculating the ratios of the glucuronides or P to creatinine (C). The peaks of estrogen glucuronides were delayed mostly by 1 day in comparison to the peaks of E2 in plasma. The urinary peaks of estrogens were in most cases more closely clustered around the day of the LH-peak when the measurements were corrected for C. For the determination of the first significant rise of steroid levels in a cycle, the calculation of a sustained rise (leading to a significant cumulative sum - CUSUM) was found superior when compared to other recommended indices, such as a 50% increase over the mean of 3 preceding values, or the increase over the baseline level plus 2 standard deviations. Sustained rises were calculated for all indices studied (including the ratio of urinary E1G to PdG). The ratio of E1G to C in morning urine gave consistently the most compact distribution of sustained rises. It is concluded that daily measurements of urinary PdG (or P) and E1G (or, possibly, E2) could substitute the serial assays of P and E2 in peripheral blood in the retrospective assessment of the ovarian functionn. The day-to-day variation can be significantly reduced, if results are expressed per concentration of C. For the prediction of ovulation or fertile period, the best index of urinary steroids appears to be the sustained rise in the ratio of E1G to C. However, this "best" method is still not good enough in terms of overall reliability and practicability.

Plasma dehydroepiandrosterone, its sulfate, testosterone and FSH during puberty of African children in Gabon

Plasma levels of dehydroepiandrosterone (DHEA), its sulfate (DHEAS), testosterone (T) and follicle stimulating hormone (FSH) were measured by radioimmunoassay in 111 schoolboys and 95 schoolgirls from 7 to 18 years. 68 male and 55 female adults aged from 19 to 25 were also investigated. Results are expressed as the mean +/- SD, DHEA was the first hormone to vary showing a significant mean increase between the 10 and 11 year age groups of both boys and girls. Higher levels were observed in the age 12 group (boys 164.70 +/- 60.74; girls 256.60 +/- 145.40 ng/dl) but were followed by a significant decrease in both 13 year old groups. Similar increases followed by decreases were also noted for DHEAS, although the increase started between 11 and 12 years and reached a maximum at 13. An abrupt increase in FSH levels between 11 and 12 years followed by a plateau through 15-18 years, was observed for boys and girls. As expected, T levels increasing significantly in boys with the initial rise between 11 and 12 and a climb through to the 15-18 age group. Our results suggest a late plasma DHEAS secretion with adult levels attained after age 19. Menarche was also found to be late.

Bromocriptine and apomorphine stimulation of cortisol secretion in conscious dogs; evidence for a stimulatory site located outside the blood brain barrier

IV injections of the dopamine receptor agonists bromocriptine (0.1 mg/kg) and apomorphine (0.05 mg/kg) induced rapid and long-lasting increases of cortisol levels as measured by RIA in peripheral venous plasma of conscious dogs. Pretreatment with dopamine receptor antagonists which do not readily penetrate the blood brain barrier (domperidone, halopemide, sulpiride) abolished the release responses induced by the dopamine agonists. These results suggest that the dopamine receptor agonists stimulate cortisol release at a site located outside the blood brain barrier. In addition, some dopamine receptor antagonists (haloperidol, chlorpromazine, milenperone) were shown to cause a rapid and long-lasting increase of cortisol levels.

Effects of progesterone, progestogens, and danazol on the specific cortisol binding in human plasma

The interaction of medroxyprogesterone acetate (MPA) with cortisol binding to corticosteroid-binding globulin (CBG) was studied with the use of an aqueous two-phase system with polyethylene glycol and dextran for equilibrium partition. Competitive binding analyses were also performed for progesterone (P), levonorgestrel, norethisterone, danazol, and tamoxifen. P and danazol were found to exert cortisol displacing activity, whereas MPA and the other tested compounds had no such effect. The glucocorticoid effects reported for MPA could not be explained by displacement. In general, P serum concentrations are lower than those of cortisol, and most binding sites on CBG are occupied by the glucocorticoid. At high P levels displacement and an increase in free cortisol may occur. Danazol displacement of cortisol is hampered by its pronounced albumin binding. In conclusion, none of the tested compounds should increase free and biologically active cortisol during normal clinical treatment.

Stage-specific inhibition of interstitial cell testosterone secretion by rat seminiferous tubules in vitro

The stage-specific influence of the secretions from rat seminiferous tubules on the LH-stimulated testosterone production by rat Leydig cells in vitro was studied. The spent media from incubated seminiferous tubules (SMST) from stages VII-VIII of the seminiferous epithelial cycle caused about 50% inhibition of the LH-dependent testosterone production by a crude preparation of rat interstitial cells. The SMST from other stages had no effect on testosterone production. Mixed tubules of unidentified stages gave an intermediate response. When SMST from ten different stages of the seminiferous wave were compared, the most pronounced inhibitory activity was found in stages VI and VIII-XI, while SMST from stages I, VII and XIII-XIV had no inhibitory effects on interstitial cell testosterone production. No stimulation was found in this system. Prolonged incubation of the interstitial cells with SMST from stages VIII-XI resulted in loss of inhibitory activity after 12 h of incubation. Maximum inhibitory activity was noted after 3 h of incubation. The inhibitory activity of the SMST from stages VIII-XI was retained after prolonged dialysis, and was unchanged after heating the medium at 60 degrees C for 1 h. The activity did not seem to be due to the presence of proteolytic enzymes, since it was not influenced by addition of protease inhibitors. SMST from stages VIII-XI had no effect on the metabolism of [3H]testosterone added to the interstitial cell preparations. No inhibitory effect was observed when Leydig cells were incubated with dibutyryl cAMP instead of LH, suggesting an early influence on the LH-receptor-adenylate cyclase chain of events.(ABSTRACT TRUNCATED AT 250 WORDS)

Reliability of progesterone measurements in urine

A radioimmunoassay (RIA) of progesterone in urine is described. After the addition of labelled progesterone, morning urine was extracted with n-hexane adn the residue was either directly subjected to RIA, or chromatographed on celite prior to RIA. The progesterone from celite chromatography was radiochemically pure. RIA after chromatography was therefore considered valid. The non-chromatographed procedure resulted in overestimations, the degree of which was inversely proportional to progesterone content. The results obtained by the two procedures were well correlated (r = 0.88 and 0.93, for 2 different groups of samples.