Effect of nasal instillation of female urine or vaginal exudate on testosterone secretion in isolated and anesthetized male rhesus monkeys (Macaca mulatta)

Two male adult rhesus monkeys were individually placed in cages with a pulling device in order to immobilize the animals for anesthesia. The room was temperature-controlled having a light/dark period of 12/12 hours. The animals were rapidly immobilized and immediately anesthetized with ketamine i. m. (10 mg/kg of body weight). They were bled four times at 15, 30, 45, and 60 mins after the ketamine injection, twice a week during 6 weeks. When necessary, maintenance doses of ketamine were administered. The levels of serum testosterone in experimental conditions (nasal instillation of female urine or a suspension of vaginal exudate) showed significant lower values with respect to those in control conditions (saline instillation). The control levels of testosterone tend to increase up to 60 mins. The testosterone from samples obtained in experimental conditions did not show such an increase, remaining similar during the sampling and similar to the 15 min control levels that could be considered as basal. These results seem to point out some chemical information from females capable of modifying the pattern of secretion of testosterone of the males in the above mentioned experimental conditions.     

Influence of restraint and ketamine anesthesia on adrenal steroids, progesterone, and gonadotropins in rhesus monkeys

Changes in gonadotropins, progesterone, cortisol, DHA, and DHAS were monitored in 10 female rhesus monkeys (Days 20-23 of the menstrual cycle) subjected to cage restraint with or without ketamine anesthesia for successive venipunctures. All animals were bled without sedation for 2 hr at 30-min intervals. Then 4 of the animals were anesthetized with ketamine-HCl and bleedings in all animals were continued for an additional 2.5 hr. FSH and progesterone were not appreciably affected by either restraint technique. LH declined steadily for the duration of the bleedings (P less than 0.05). Serum levels of cortisol and the adrenal androgens increased twofold (P less than 0.05). Anesthesia with ketamine had no effect on any of the six variables when compared with saline controls. Cortisol and dehydroepiandrosterone (DHA) levels tended to plateau (P less than 0.01) after 2 hr in both treated and control groups. In contrast, dehydroepiandrosterone sulfate (DHAS) levels increased continuously throughout the entire study period. These data indicate that ketamine anesthesia does not alter endocrine responses to venipuncture when administered following cage restraint of conscious animals. These findings further confirm the difficulties in obtaining estimates of basal levels of hormones which are responsive to stress and suggest that the first sample may provide the best estimate.     

Measurement of serum prolactin and the effect of ketamine anesthesia on serum prolactin levels in cynomolgus monkeys (Macaca fascicularis)

The effect of an anesthetic, ketamine, on the serum prolactin level was examined in wild-originating female cynomolgus monkeys (Macaca fascicularis) imported from South East Asia. Serum prolactin levels were measured by the homologous radioimmunoassay system which was developed for human prolactin. The validity was confirmed by using an extract of pituitary gland from a female cynomolgus monkey as well as serum and amniotic fluid from a pregnant monkey. Additionally, serum luteinizing hormone (LH) levels were determined by the radioreceptor assay system developed in our laboratory using Leydig cells collected from rat's testes as a receptor fraction. The experiment was repeated three times at one-month interval, using twenty animals that were divided into three groups consisting of 5, 7 and 8 monkeys each. In the first experiment, the first group was injected with physiological saline and the second and third groups were intramuscularly given ketamine at a dose level of 5 mg/kg B.W. and 15 mg/kg B.W., respectively. In the second experiment, the first and second groups were given ketamine at a dose of 5 mg/kg B.W. and of 15 mg/kg B.W., respectively, and the third group was served as control injected with saline. In the third experiment, the first and third groups were administered with 15 mg/kg and 5 mg/kg of ketamine and the second group was injected with saline. In short, all of the twenty monkeys received the three different treatments for two months. The serum prolactin level showed a marked increase after the administration of ketamine.(ABSTRACT TRUNCATED AT 250 WORDS)     

The effects of different anaesthetic treatments on the adreno-cortical functions and glucose levels in NZW rabbits

The effects of five anaesthetics on the corticosterone, cortisol and glucose concentrations were investigated in the NZW rabbit. Sixty animals were assigned to 6 treatment groups (n= 10 per group): control ( iv saline solution injection), ketamine (10 mg/kg iv) with either xylazine (3 mg/kg iv) or diazepam (2 mg/kg iv), pentobarbitone (30 mg/kg iv), thiopentone (20 mg/kg iv) and fentanyl/droperidol (1 mg/kg sc). Plasma glucocorticoids were measured by competitive enzymeimmunoassay EIA and glucose by an autoanalyzer, previously validated for this species in both cases. Blood samples were obtained at 6 time-points: before injection, at 10, 30, 60, 120 min and 24 h after injection of the anaesthetics/saline. A significant decrease of plasma glucocorticoids at 10-60 min was observed in the pentobarbitone and fentanyl/ droperidol groups, whereas the administration of ketamine/diazepam or thiopentone stimulated plasma glucocorticoid release, principally in the recovery period. However, in the ketamine/xylazine group no changes were observed in the glucocorticoid levels, except for a significative increase of cortisol at 60-120 min. Glucose levels significantly increased after ketamine/diazepam administration and principally, after ketamine/xylazine treatment. The present data suggest that ketamine/xylazine has little effect on glucocorticoid levels and provides an adequate level of surgical anaesthesia, hence it would be the anaesthetic of choice, although the hyperglycaemic effect after injection has to be considered for any experimental procedures in rabbits.     

Effects of spreading depression on stress-induced changes in plasma prolactin and LH.

Female rats rendered "pseudopregnant" by treatment with PMS and hCG and ovariectomized rats injected with estradiol and progesterone (OVX-E2-P) were subjected to cortical spreading depression (SD). Within 7-10 min under ether anesthesia in a stereotaxic instrument a frontal craniotomy was performed and a cotton ball saturated with physiological saline (control) or 25% KCl was applied to the exposed dura, covered with dental cement and skin sutured. The animals were then placed in separate containers in an isolated room and decapitated for collection of trunk blood at 0, 15, 30, or 60 min after surgery. In PMS-hCH saline-treated control animals, prolactin levels had dropped by 15 and 30 min when compared with the zero-time values but by 60 min had increased significantly above the 30-min level. At that time (60 min), prolactin values in the KCl group were significantly lower than in the controls. Corticosterone levels were high at both 15 and 60 min in control and KCl groups. In OVX-E2-P control animals, plasma prolactin levels also rose at 60 min compared with 15- and 30-min samples and at 60 min were significantly higher than in the KCl group. In control animals, LH levels were lower at 15 and 60 min than at zero time, but they remained unchanged in the KCl group. The dato are interpreted as indicating that cortical SD suppresses the stress responses observed in saline-treated control animals.     

The effects of ketamine anesthesia on hematological and serum biochemical values in female cynomolgus monkeys (Macaca fascicularis)

The effects of ketamine anesthesia (15 mg/kg body weight) on hematological and serum biochemical values were examined in six female cynomolgus monkeys (Macaca fascicularis) who were born in the wild. As control, another six female cynomolgus monkeys of the same origin were injected with physiological saline. The white blood cell count, total protein concentration, albumin concentration and calcium concentration decreased after the injection of ketamine, whereas the red blood cell count, hematocrit value, hemoglobin concentration, total cholesterol concentration, free cholesterol concentration, triglyceride concentration, transaminase activities (GOT, GPT) and alkaline phosphatase activity were not affected. A transient increase of the serum glucose level was observed within 10 minutes after ketamine injection. The relationship between these effects of ketamine anesthesia and serum cortisol levels measured by radioimmunoassay was discussed.     

Cortisol responses to immobilization with Telazol or ketamine in baboons (Papio cynocephalus/anubis) and rhesus macaques (Macaca mulatta)

Little is known about the influence of Telazol on cortisol or of anesthetic agents on immunological measures, and reports of ketamine's effect on cortisol are inconsistent. We measured effects of Telazol, ketamine and blood sampling on cortisol in male rhesus macaques and male savannah baboons. We also obtained leukocyte counts in the macaques. In macaques, Telazol reduced cortisol in the morning but not in the afternoon; ketamine had no effect on cortisol in these animals. In baboons, cortisol changed little post-Telazol but increased post-ketamine. In macaques, lymphocyte numbers decreased following afternoon injection of Telazol, ketamine or saline. The injection and blood sampling process increased cortisol levels in monkeys not trained to extend an arm but exerted no effect on cortisol in trained macaques. Thus, the animals' physiological responses to blood sampling and immobilization are influenced by such variables as anesthetic agent, species, time of day, and familiarity with the blood sampling process.     

Restoration of fertility in light-deprived female hamsters by chronic melatonin treatment

Summary Blinding young adult female hamsters was followed by functional involution of the ovaries and uteri and by the cessation of cyclic vaginal phenomena. Light deprivation was also accompanied by elevated plasma and pituitary levels of luteinizing hormone and depressed levels of prolactin in both the blood and the pituitary gland. Only one of 15 blinded hamsters became pregnant when they were exposed to fertile males for 30 days. Both pinealectomy or chronic melatonin treatment (1 mg melatonin implanted subcutaneously per week in beeswax) prevented the changes in the reproductive organs and in pituitary hormone levels attendant on light-deprivation. Both treatment also returned vaginal cycles to normal and restored plasma prolactin titers. Unlike hamsters that were blinded only, light deprived hamsters that were either pinealectomized or melatonin treated were capable of reproducing when they were caged with fertile males. The reproductive capability (i.e., percent of animals that become pregnant and the sizes of their litters) of these animals was equivalent to that of the untreated control hamsters. This is the first report that chronic melatonin treatment restores fertility in blinded female hamsters.Supported by Grant GB-43233X from the National Science Foundation     

Effects of short-term stress, xylazine tranquilization and anesthetization with xylazine plus ketamine on plasma concentrations of cortisol, luteinizing hormone, follicle stimulating hormone and prolactin in ovariectomized pony mares

Long-term ovariectomized pony mares were subjected to one of four treatments: 1) control group - no treatment, 2) stressed group - 5 min of restraint via a twitch, 3) tranquilized group - administered xylazine (1.1 mg i.v. per kg of body weight), and 4) anesthetized group - administered xylazine followed 2 min later by ketamine (2.2 mg i.v. per kg of body weight). Blood samples were taken at -40, -30, -20, -10, -0.5, 10, 20, 30, 40, 50, 60 and 90 min and at 2, 3, 4, 6, 8 and 24 h relative to onset of treatment. Stress increased (P<0.05) cortisol concentrations 20 to 50 min after treatment and again at 6 and 8 h. Tranquilization had no effect on cortisol concentrations, whereas anesthetization increased (P<0.05) cortisol concentrations from 90 min through 8 h after treatment. Concentrations of luteinizing hormone (LH) and follicle stimulating hormone (FSH) did not vary (P>0.1) relative to pretreatment in any group of mares. Concentrations of prolactin were 2.7-fold higher (P<0.05) 24 h after treatment in all four groups, indicating some procedural or environmental influence on prolactin secretion. There was a transient increase (P<0.06) in prolactin concentrations in anesthetized mares 30 min after treatment. Although two of these three commonly used methods of restraint did affect cortisol concentrations, there was no effect on plasma concentrations of LH or FSH. Thus, we conclude that such methods of restraint can be used in short-term situations without disturbing estimates of LH and FSH secretion. However, when prolactin concentrations are to be measured, anesthesia with ketamine should not be used.     

Neurotensin inhibits LH release

The present studies were designed to assess the effect of neurotensin on the release of LH, FSH, and prolactin in long-term castrated female rats. The animals were implanted in the lateral ventricle of the brain wih a cannula to allow the administration of either neurotensin or the vehicle. The peptide (30 microgram, dissolved in saline) or the control saline solution was injected intraventricularly in a volume of 10 microliter following pentobarbital anesthesia. Blood samples were collected at sacrifice 15, 30 and 60 min after injection. A significant decrease of serum LH levels was already present in neurotensin-treated animals at 15 min, and was maintained up to the end of the experiment. This decrease was not accompanied by any change in FSH or prolactin secretion. The results suggest that this tridecapeptide participates in the control of LH release and provide new data on the separate control of the release of the two gonadotropins.     

Urinary and fecal immunoglobulin A, cortisol and 11-17 dioxoandrostanes, and serum cortisol in metabolic cage housed female cynomolgus monkeys (Macaca fascicularis)

BACKGROUND AND METHODS: Quantitative enzyme-immunoassays of urinary and fecal immunoglobulin A (IgA), cortisol and 11-17-dioxoandrostanes (11,17-DOA), and serum cortisol in eight metabolic-cage-housed female cynomolgus monkeys were performed. The monkeys were divided into two groups, B and NB. Group B animals were blood sampled every 6 hours, whereas Group NB animals were not handled/blood sampled. RESULTS: No differences were recorded between the amounts of feces and urine excreted by the two groups. Group B animals excreted more urinary cortisol than did Group NB animals indicating that restraint-blood sampling resulted in a stress response. Excreted amounts of IgA and 11,17-DOA (urine and feces) did not differ between the groups. CONCLUSIONS: Urinary cortisol was a reliable marker of the stress associated with repeated blood sampling. Declining amounts of excreted urinary cortisol indicated that cynomolgus monkeys acclimated quickly to repeated blood sampling in metabolism cages. Within and between animal variation in amounts of feces voided demonstrated the importance of expressing fecal markers as 'amounts excreted per time unit per kg body weight' rather than just measuring the concentrations in fecal samples.     

Circulating LH, FSH, prolactin, testosterone, delta 4-androstenedione, dehydroepiandrosterone sulfate and cortisol levels in the fetus in late gestation and in newborn male and female lambs

Gonadotropins, prolactin (PRL), testosterone (T), delta 4-androstenedione, dehydroepiandrosterone sulfate and cortisol (F) levels were determined from 14 days before birth to term in 3 female and 3 male ovine fetuses with a chronically implanted venous catheter, and in the same animals from birth to 72 h of age. In both sexes, plasma gonadotropins and androgens were low throughout the period of study while plasma F increased with gestational age. After birth, plasma gonadotropins and PRL tended to increase progressively with time while PRL concentrations were significantly higher in female than in male lambs. F and T concentrations decreased significantly within the first 12 and 6 h of postnatal life. Higher T values were again observed at 36 h in male lambs. These data indicate that the fetal hypothalamic-pituitary-gonadal axis is relatively quiescent in the last 14 days of gestation but is activated within the first 72 h after birth.     

Inhibition of ovarian function in subordinate female marmoset monkeys (Callithrix jacchus jacchus)

Plasma concentrations of progesterone, cortisol, LH and prolactin were measured in dominant and subordinate female marmosets in 10 well-established peer groups. Subordinate females never ovulated, had a reduced LH response to LH-RH and showed no positive feedback LH surge after oestrogen administration. There was no evidence of elevated plasma cortisol levels or hyperprolactinaemia in subordinates and all showed a similar prolactin response to TRH in comparison with dominants. However, subordinates showed a reduced prolactin response to metoclopramide. These results clearly indicate that high circulating levels of cortisol or prolactin are not responsible for the inhibition of ovulation in female marmosets.     

Effect of anxiolytics--buspirone and diazepam--on the prolactin, thyrotropin and cortisol content of the blood in the green monkey

The influence of two anxiolytics--diazepam and buspirone--on prolactin, thyrotrophin and cortisol levels in green monkey (Cercopithecus aethiops) plasma was studied 30 min following i/m injection. Diazepam at 1 mg/kg decreased prolactin and cortisol levels by 30-50% compared to the control animals. Buspirone at 2.5-10 mg/kg induced a 7-10-fold increase in prolactin level but did not change cortisol and thyrotrophin concentration. Buspirone analog--Mj 138-05 at 10 mg/kg produced a 2-3-fold increase in plasma prolactin content in some animals, while at a dose of 5 mg/kg it exerted no detectable effect. Possible neurochemical mechanisms of the effects observed are discussed.     

Vaginal myeloperoxidase and flora in the pig-tailed macaque

Myeloperoxidase (MPO) is an enzyme in neutrophils and monocytes which reacts with H₂O₂ and chloride to kill microbes after phagocytosis. Instillation of MPO into the vagina may augment vaginal defenses against sexually transmitted diseases, since the normal vaginal flora is characterized by the presence of H₂O₂-producing lactobacilli. We assessed the menstrual cycle stage, vaginal flora, pH, macroscopic appearance, and endogenous MPO in the adult female pig-tailed macaque ( Macaca nemestrina ) at baseline (n=26; 60 observations) and at 0, 4, and 24 hours in untreated animals (n=6) or in animals treated with intravaginal MPO gel at time 0 (n=5). Baseline MPO levels were highly variable, and there was no detectable effect of cycle stage. In untreated animals, there was no significant effect of vaginal swab collection on vaginal flora or MPO levels. MPO treatment did not reduce vaginal H₂O₂-producing organisms, and vaginal MPO levels tended to increase at 4 hours in treated animals. Vaginal/cervical colposcopic changes were not detected in either group.     

Abstracts of papers to be presented at the Tenth Annual Meeting of the American Society of Primatologists Madison,Wisconsin June 13–16, 1987

Invasive surgical procedures are often used to study the reproductive and adrenocortical endocrine systems in primates. Anesthetic agents must, therefore, be used that have the least confounding effects on these systems. The present study was designed to characterize various adrenocortical endocrine responses of female baboons (Papio anubis), each treated for 120 minutes with an infusion of ketamine HCl (6 mg/min) in 5% dextrose in water (0.40 ml/min), a combination of ketamine and acetylpromazine (0.6 mg acetylpromazine and 6 mg ketamine HCl/min) in 5% dextrose in water, or inhalation of vaporized halothane (1.0% halothane, N₂O 25%, 1 liter/min; O₂ 75%, 3 liters/min). Blood samples were collected throughout the treatment period, and serum was assayed for prolactin (PRL), dehydroepiandrosterone (DHA), dehydroepiandrosterone sulfate (DHAS), and cortisol (F). No significant elevations in DHA, F, or PRL concentrations were found following infusion of ketamine alone. Only serum DHAS concentrations were significantly altered after long-term exposure to ketamine. Acetylpromazine increased PRL concentrations tenfold to levels significantly greater than those in ketamine- and halothane-treated animals but had no effect on serum DHA, DHAS, or F. Treatment with halothane had no effect on serum PRL, DHA, or DHAS but did suppress F (>40%) concentrations over time. These data indicate that ketamine is best suited for the collection of biological samples when deep analgesia is not required but that halothane is preferable in the latter situation.     

Clinical, biological and hormonal study of mid-pregnancy termination in cats with aglepristone

In order to evaluate the efficacy, the safety and the variation in plasma concentrations of estrogens, progesterone, PGFM, oxytocin, cortisol and prolactin after mid-pregnancy termination induced by aglepristone, 61 pregnant queens (33.3 + 4.2 days), were injected subcutaneously with 15 [corrected] mg/kg aglepristone, (Alizine) [corrected] repeated once 24 h later. Five queens served as control and received a placebo. The efficacy of aglepristone was 88.5% and termination of pregnancy was achieved in 50% of the queens within 3 days. Brief periods of depression and anorexia were noted in 9.3% of the queens before fetal expulsion (these symptoms were attributed to the phenomenon of fetal expulsions). Not one of the queens that aborted developed uterine disease. There were no changes in plasma concentrations of estrogen, prostaglandin, prolactin or oxytocin following aglepristone administration. However, there were significant increases in plasma concentrations of progesterone and cortisol 60 and 30 h, respectively, after aglepristone administration. Termination of pregnancy occurred with high plasma progesterone concentrations. Fetal expulsion was characterised by an increase in estrogen, PGFM and oxytocin concentrations, whereas prolactin and cortisol levels remained at a basal level.     

Hormonal correlates of human paternal interactions: a hospital-based investigation in urban Jamaica

To expand our understanding of the neuroendocrine mechanisms underlying human fatherhood, including its cross-cultural expression, we investigated the hormonal correlates of fatherhood in the greater Kingston, Jamaica area. We recruited 43 men, aged 18-38, to participate: 15 single men; 16 "coresidential" fathers (men who live with their adult female partner and youngest child); and 12 "visiting" fathers (men who live apart from their adult female partner and youngest child). The research protocol entailed biological sampling before and after a 20-min behavioral session during which single men sat alone and fathers interacted with their partner and youngest child. Hormone measures relied upon minimally invasive techniques (salivary testosterone and cortisol, finger prick blood spot prolactin, urinary oxytocin and vasopressin). Results revealed significant group differences in average male testosterone levels (p=0.006), with post hoc contrasts indicating that visiting fathers had significantly (p<0.05) lower testosterone levels than single men. Prolactin profiles also differed significantly across groups (p=0.010) whereby post hoc contrasts showed that prolactin levels of single men declined significantly compared with the flat levels of visiting fathers (p<0.05). No group differences in cortisol, oxytocin or vasopressin levels were observed. However, among fathers, vasopressin levels were significantly and negatively (r=-.431, p=0.022) correlated with the age of a man's youngest child. These results thus implicate lower testosterone levels as well as prolactin and vasopressin in human fatherhood. These findings also highlight the importance of sociocultural context in human fatherhood while exhibiting parallels with existing data on the non-human vertebrate hormonal bases of paternal care.     

Urine collection in the common marmoset (Callithrix jacchus) and its applicability to endocrinological studies

We investigated a new method of urine collection in the common marmoset. We entered the cage as soon as the light cycle started in the breeding room and collected urine from the animal directly without any restraint. We were able to take separate samples from completely different individuals housed together for behavioral studies in the same cage. Urine and blood samples were taken from individuals from late pregnancy through postpartum nursing period. Cortisol and prolactin concentrations measured in urine were compared to those measured in blood to evaluate this collection method. LH/CG level in the urine samples was also measured. Urine data in females indicated a tendency toward high cortisol values during late pregnancy, a sharp drop before parturition, and increase after delivery. In females cortisol levels measured in blood closely resembled concentrations measured in urine. Urine cortisol in males clearly indicated an increase postpartum, but the increase was not indicated in plasma. Plasma and urine prolactin concentrations in females made a similar increase during lactation. Male's plasma prolactin clearly indicated an increase directly proportional to strong behavioral contact with the infant. We also confirmed hormonal changes during pregnancy, and postpartum ovulation and subsequent pregnancies, from urine LH/CG data. We found this method extremely useful because of the high correlation between cortisol, prolactin and LH/CG data from blood and urine. Additionally, we collected urine samples with little stress to the animal from fear, irritation, pain, etc.     

Exercise training and the differential prolactin response in male and female rats

Adult male and female Sprague-Dawley rats were trained on a horizontal treadmill for 0, 1, 3, 5, or 7 days/wk for 10 wk. Speed and duration were progressively increased over 5 wk to a maximum of 20 m/min for 1 h. Between weeks 9 and 10 of training, animals were placed on the nonmoving treadmill, and blood (500 microliters) was sampled via chronic venous cannulas 30 min before, 0, 10, 20, 30, 45, and 60 min during exercise, and 15, 30, 60, 90, and 120 min after exercise. In another study, resting animals in the various groups were injected with thyrotropin-releasing hormone (TRH; 2 micrograms/kg for males and 0.4 microgram/kg for females) to determine pituitary prolactin responsiveness. In males, exercise induced a significant increase in plasma prolactin levels, with the greatest increase observed in the least trained and the smallest increase in the most highly trained animals. Female rats displayed the opposite trend with the greatest increase in prolactin secretion observed in the highest trained and the smallest increase observed in the least trained animals. TRH induced similar increases in plasma prolactin in all male groups, whereas TRH-induced prolactin release was greatest in the highest trained and smallest in the least trained females. The reduced prolactin response in highly trained males may reflect their acclimation to repetitive exercise stress, whereas the enhanced response in the highly trained female rats appears to result from increased pituitary sensitivity to prolactin-releasing factors.