EFFECTS OF TESTOSTERONE PROPIONATE TREATMENT OF NEONATALLY OVARIECTOMIZED RATS ON GROWTH AND SUBSEQUENT RESPONSIVENESS TO OESTROGEN

1976 ◽  
Vol 82 (3) ◽  
pp. 652-660 ◽  
Author(s):  
M. F. Tarttelin ◽  
J. E. Shryne ◽  
R. A. Gorski
Keyword(s):  
Body Weight ◽  
Testosterone Propionate ◽  
Neonatal Period ◽  
Specific Effect ◽  
Ovariectomized Rats ◽  
Inhibitory Effects ◽  
Androgen Treatment ◽  
Ovx Rats ◽  
Significant Difference ◽  
Oestradiol Benzoate

ABSTRACT There was no significant difference in body weight between neonatally ovariectomized (OvX) rats whether given oil treatment or 90 μg testosterone propionate (TP) on day 3, when examined up to 23 weeks of age. When these two animals were injected with oestradiol benzoate (3 μg/day for 2 weeks), the neonatally OvX TP treated rats showed a significantly smaller depression in body weight than did the control neonatally OxX rats. Measurement of food intake also showed that TP treated rats responded significantly less to the depressant effects of oestrogen than did the controls. These data are consistent with the hypothesis that the ovary does restrain body weight in TP rats but that androgen treatment in the neonatal period may not have a specific effect on growth but may alter the sensitivity of growth regulating processes to the inhibitory effects of oestrogen.

OESTROGEN RESPONSES OF RATS NEONATALLY STERILIZED WITH STEROIDS

1969 ◽  
Vol 45 (3) ◽  
pp. 415-420 ◽  
Author(s):  
T. R. WRENN ◽  
JOAN R. WOOD ◽  
J. BITMAN
Keyword(s):  
Testosterone Propionate ◽  
Female Rats ◽  
Ovariectomized Rats ◽  
Uterine Weight ◽  
Oestradiol Benzoate

SUMMARY At 75 days of age, female rats neonatally sterilized with oestradiol benzoate or testosterone propionate were compared with normal and ovariectomized rats with regard to their 6-hr. response to 0·2 μg. oestradiol 17β. The greatest increases in uterine weight, glucose and glycogen concentrations and per cent uterine water occurred in the ovariectomized animals. A marked oestrogen response also occurred in the animals neonatally sterilized with oestradiol benzoate. The response of the normal rats was slight, and the testosterone propionate-treated rats were the least affected. Adrenal, pituitary, and ovarian weights were found to be affected by the neonatal hormone treatments. Vaginal patency was completely inhibited in the rats injected with testosterone propionate. It is concluded that rats neonatally sterilized with steroids are much less suitable than ovariectomized animals for oestrogen assays.

Adrenal progesterone facilitates the negative feedback of oestrogen on LH release in ovariectomized rats

1993 ◽  
Vol 139 (2) ◽  
pp. 253-258 ◽  
Author(s):  
A. M. Salicioni ◽  
R. W. Carón ◽  
R. P. Deis
Keyword(s):  
Ovariectomized Rats ◽  
Adrenal Steroids ◽  
Serum Progesterone ◽  
Oestrogen Treatment ◽  
Ovx Rats ◽  
Serum Lh ◽  
Oestradiol Benzoate ◽  
Lh Release ◽  
Lh Secretion

ABSTRACT There is evidence that the adrenals play a role in the regulation of the synthesis and release of gonadotrophins in various vertebrates. The aim of this study was to determine the part played by adrenal steroids, with special reference to progesterone, on the concentration of LH in ovariectomized (OVX) and oestrogen-primed rats. OVX rats received a single s.c. injection of vehicle or oestradiol benzoate (OB, 20 μg/rat). This day was designated as day 0. Three or four days later (day 3–day 4), the rats were treated with mifepristone (10 mg/kg) or with two doses of progesterone antiserum and blood samples were obtained at 13.00 and 18.00 h. OB treatment of OVX rats reduced serum LH at 13.00 h and 18.00 h on day 3 but only at 13.00 h on day 4. The administration of mifepristone at 08.00 h to OVX and oestrogen-treated rats induced a significant increase in serum LH at 18.00 h on days 3 and 4, without modifying the values at 13.00 h. When mifepristone was given at 13.00 h a much larger increase in serum LH was obtained at 18.00 h. In OVX and oestrogen-treated rats, adrenalectomy on day 2 (08.00–09.00 h) induced an increase in serum LH at 18.00 h similar to that observed in the OVX and oestrogen-primed rats after mifepristone treatment. In order to determine the specificity of the effect of mifepristone, a group of OVX and oestrogentreated rats was injected with progesterone antiserum at 08.00 and 13.00 h on day 3. Serum LH concentrations at 13.00 and 18.00 h on day 3 were similar to values obtained in OVX rats treated with oestrogen and mifepristone. Serum progesterone was measured at 08.00 and 13.00 h in OVX and OVX and oestrogenprimed rats. At both times, values were similar in OVX rats but oestrogen treatment significantly increased serum progesterone levels. The important role of adrenal progesterone on the regulation of LH secretion in OVX and oestrogen-primed rats is evident from these results. Blocking progesterone action at the receptor level, we showed that OB significantly increased LH values at 18.00 h. On the basis of these studies it is tempting to speculate on the possibility of an inhibitory or stimulatory effect of oestrogen on serum LH concentration in OVX rats, according to the presence or absence of adrenal progesterone action. Journal of Endocrinology (1993) 139, 253–258

Leptin and neuropeptide Y levels in newborns

2016 ◽  
Vol 29 (1) ◽  
Author(s):  
Avni Kaya ◽  
Zerrin Orbak ◽  
İsmail Polat ◽  
Harun Polat ◽  
Musa Gümüşdere
Keyword(s):  
Body Weight ◽  
Prospective Study ◽  
Neuropeptide Y ◽  
Neonatal Period ◽  
Medical Faculty ◽  
Faculty Research ◽  
Research Hospital ◽  
Significant Difference ◽  
The Mean ◽  
Plasma Leptin

AbstractSeveral studies have investigated leptin and neuropeptide Y (NPY) levels in children, but the information for newborns in the literature is limited. The purpose of this study was to determine leptin and NPY levels in 14- to 28-day-old newborns.This prospective study was performed in Atatürk University Medical Faculty Research Hospital Neonatal Clinic, Erzurum, Turkey between July and December, 2014. Sixty-two 14- to 28-day-old neonates, 26 female and 36 male, were included. Age, height, and body weight of the patients were recorded. Feeding status was also recorded. The newborns were divided into two groups – those receiving breastfeeding only and those receiving breastfeeding and formula. Plasma leptin levels were measured using enzyme amplified sensitivity immunoassay (EASIA).The mean leptin level in 14- to 28-day-old female neonates was 4.25±3.08 ng/mL, and the mean NPY level was 24.79±9.87 ng/mL. The mean leptin level in 14- to 28-day male neonates was 3.49±2.52 ng/mL, and the mean NPY level was 25.80±9.58 ng/mL. No significant difference was determined between leptin (p=0.228) or NPY (p=0.144) in terms of feeding status. No significant difference was also observed between the sex in terms of leptin or NPY levels (leptin p=0.775 and NPY p=0.687).There were no differences in terms of feeding status and sex in leptin and NPY levels in the neonatal period.

SERUM CORTICOSTERONE IN RATS WITH DELAYED ANOVULATION

1976 ◽  
Vol 71 (1) ◽  
pp. 31-36 ◽  
Author(s):  
JUDITH A. RAMALEY
Keyword(s):  
Low Dose ◽  
Testosterone Propionate ◽  
Ovariectomized Rats ◽  
Tube Length ◽  
Blood Levels ◽  
Early Exposure ◽  
Vaginal Opening ◽  
Adrenal System ◽  
Oestradiol Benzoate ◽  
Intact Rats

SUMMARY The purpose of this study was to investigate adrenal function in rats during the development of persistent oestrus to determine whether a change in blood levels of corticosterone would precede or coincide with the onset of infertility. The syndrome of delayed persistent oestrus and anovulation was induced by administration of a low dose (10 μg) of testosterone propionate (TP) at 5 days of age. Control animals were handled without injection or received the vehicle (sesame oil) only. Half of each group was ovariectomized at weaning and received Silastic implants of either oestradiol benzoate (OB) or cholesterol, 3 mm tube length/100 g body weight. Intact rats given the low TP dose showed precocious vaginal opening (27·3 ± 2·1 days v. 37·6 ± 2·4 (s.e.m.) days in unhandled controls) and ovulated within 2 days. Persistent vaginal cornification developed in 22 out of 26 rats by 75 days of age. The TP-treated rats had higher corticosterone values than the controls and did not show a further increase after OB implantation. Cholesterol implantation depressed corticosterone levels in the TP-treated rats. The effects of the low TP dose were not dependent upon gonadal function since they persisted in ovariectomized rats. The results suggest that early exposure to androgen can modify the sensitivity of the adrenal system to oestrogen, and can also lead to persistently high values of corticosterone which are not depressed by ovariectomy. These changes precede the onset of persistent oestrus.

PROGESTERONE TREATMENT INCREASES PITUITARY OESTRADIOL RETENTION IN THE OVARIECTOMIZED NORMAL FEMALE RAT BUT NOT IN THE MALE NOR IN THE ANDROGEN- OR OESTROGEN-STERILIZED FEMALE RAT

1977 ◽  
Vol 84 (2) ◽  
pp. 268-280 ◽  
Author(s):  
Robert D. Lisk ◽  
Lawrence A. Reuter
Keyword(s):  
Testosterone Propionate ◽  
Ovariectomized Rats ◽  
Normal Female ◽  
Nuclear Fraction ◽  
Female Rat ◽  
Treatment Conditions ◽  
Oestradiol Benzoate ◽  
Pre Treatment

ABSTRACT Pituitary retention of [3H]oestradiol in ovariectomized rats was measured following in vivo progesterone pre-treatment and found to be significantly increased after 48, 72, 96 and 120 h of pre-treatment. Increased [3H]oestradiol retention was also observed for at least up to 72 h after removal of the progesterone pre-treatment source. This retention was measured as dpm per mg dry tissue weight. [3H]Oestradiol retention was also measured in the nuclear fraction of tissues incubated with [3H]oestradiol in vitro. Following 72 h of in vivo progesterone pre-treatment, the nuclear fraction from the pituitary was found to retain significantly more [3H]oestradiol than corresponding fractions from non-treated animals. In contrast to ovariectomized females, no increase in [3H]oestradiol retention was found in the pituitary of orchidectomized males pre-treated with progesterone for 72 h. [3H]Oestradiol retention by pituitaries of ovariectomized rats injected on the day of birth with 200 μg oestradiol benzoate (OeB) or 500 μg testosterone propionate (TP) was significantly decreased in comparison to control animals. When the rats were pre-treated in vivo with oestradiol for 6 or 72 h and [3H]oestradiol retention was measured 6 or 24 h after this pre-treatment, the OeB and TP treated animals retained significantly less [3H]oestradiol under most treatment conditions. Progesterone pretreatment for 24 or 72 h in vivo followed by measurement of [3H]oestradiol retention immediately or 6 or 24 h later resulted in a significant increase in [3H]oestradiol retention for the control animals. In contrast, the neonatally OeB or TP treated animals differed significantly by not showing increased retention. When [3H]oestradiol retention of the pituitary was measured in vitro following homogenization at 0°C and incubation at 37°C for 1 h, the nuclear fraction from both OeB and TP treated animals was found to retain less hormone per unit DNA; however, this decrease was significant only for the TP animals. Thus, males and androgen- or oestrogensterilized females have an altered and reduced augmentation of pituitary oestradiol retention in response to both oestrogen and progesterone pretreatments.

scholarly journals Androgen responsiveness of the liver of the developing rat

1974 ◽  
Vol 144 (2) ◽  
pp. 225-229 ◽  
Author(s):  
J-Å Gustafsson
Keyword(s):  
Testosterone Propionate ◽  
Neonatal Period ◽  
Female Rats ◽  
Male Rats ◽  
Second Phase ◽  
Final Phase ◽  
Male And Female ◽  
Androgen Treatment ◽  
Male And Female Rats ◽  
Developing Rat

The activities of the hepatic microsomal 2α-, 2β-, 7α- and 18-hydroxylase systems active on 5α-[4-14C]androstane-3α,17β-diol were studied in male and female rats which had been castrated at birth and at the age of 7, 13, 21, 27, 34, 43 and 55 days, treated for 5 days with 2mg of testosterone propionate/kg body weight and killed 6 days after castration. The 7α-hydroxylase system was affected very little by androgen treatment at all stages during development. On the other hand it was found that the rat liver passed through three phases during development with respect to androgen responsiveness as judged by changes in the activities of the 2α, 2β- and 18-hydroxylase systems: a first phase (from the neonatal period up to about 19 days of age) with a relative androgen unresponsiveness in both male and female rats, a second phase (from about 27 to about 33 days of age) when male and female rats responded equally well to androgens and a final phase (from about 40 days of age) with a successively decreasing androgen responsiveness in female rats but with a retained responsiveness in male rats. The hypothesis is presented that neonatal imprinting of the liver by testicular androgen(s) determines the development and degree of androgen responsiveness of liver tissue in the rat.

Therapeutic Effect of Selected Biomaterials (Mg/Zn/F-CaPs, Administered by Injection) on Bone Properties of Ovariectomized Rats

2006 ◽  
Vol 309-311 ◽  
pp. 243-246 ◽  
Author(s):  
Makoto Otsuka ◽  
Ayako Oshinbe ◽  
Atsuo Ito ◽  
Kuniko Otsuka ◽  
William I. Higuchi ◽  
...  
Keyword(s):  
Therapeutic Effect ◽  
Bone Mineral ◽  
Area Under The Curve ◽  
Ovariectomized Rats ◽  
Control Group ◽  
Mineral Density ◽  
Bone Properties ◽  
Ovx Rats ◽  
Significant Difference ◽  
The Right

The purpose of this study was to evaluate the efficacy of magnesium (Mg), zinc (Zn) and fluoride (F)-containing calcium phosphate compounds (Mg/Zn/F-CaP) in correcting the bone mineral deficiency noted in ovariectomized (OVX) rats. In order to evaluate therapeutic effect of selected Mg/Zn/F-BCP preparations (G2: 1.13%Mg/13.6%Zn/2.5%F, G3:7.76%Mg/1.89%Zn /3.01%F and G4:2.72%Mg/3.75%Zn/1.35%F), suspensions consisting of Mg/Zn/F-CaP preparations and of Zn-TCP (G1: 6.17%Zn) powder were injected in the right thigs of OVX rats for 4 weeks. Injection of Zn-TCP powder suspension in G1 and G2 groups led to the recovery of plasma Zn levels in OVX rats. The area under the curve of plasma Zn for the G2, G1 and Normal (not ovariectomized) control group (GN) groups were significantly lower than those of the group G3, G4 and OVX /untreated control (GC) groups (p<0.05). The bone mineral density (BMD) of the right femur was significantly higher than that of the left in G1, G2, G3 and G4 groups on day 28. However, there was no significant difference in the BMD between the left and right femur in the GC and GN groups.

EFFECTS OF DIHYDROTESTOSTERONE AND OESTRADIOL ON SEXUAL DIFFERENTIATION IN MALE RATS

1980 ◽  
Vol 84 (3) ◽  
pp. 397-407 ◽  
Author(s):  
P. VAN DER SCHOOT
Keyword(s):  
Sexual Differentiation ◽  
Testosterone Propionate ◽  
Neonatal Period ◽  
Combined Treatment ◽  
Female Rats ◽  
Male Rats ◽  
Normal Male ◽  
Oestradiol Benzoate ◽  
The Brain ◽  
Copulatory Behaviour

Adult male rats which had been castrated at birth and treated with the non-aromatizable androgen dihydrotestosterone propionate (DHTP) showed incomplete copulatory behaviour. When tested with oestrous female rats during treatment with testosterone propionate (TP) they readily mounted these females and showed frequent penile intromissions but rarely ejaculated. In a long series of observations the proportion of ejaculating rats in tests of 30 min did not exceed 50%. Neonatally castrated rats treated with DHTP during infancy thus seemed to be capable of ejaculation in adulthood during treatment with TP, but the threshold for the occurrence of the ejaculatory reflex seemed to be higher than in normal male rats. By replacing treatment in adulthood with TP by a combined treatment with DHTP and oestradiol benzoate (OB), the frequency of ejaculation was not increased. It was concluded that the incomplete copulatory behaviour was not due to reduced efficiency of aromatization of androgen within the brain of these rats. The addition of OB to DHTP during the neonatal period of treatment enhanced the frequency of ejaculation in adulthood. The combined treatment of 0·1 mg DHTP on days 1, 3 and 5 with 0·01 mg OB on day 1 made adult copulatory behaviour during treatment with TP indistinguishable from that of rats castrated on day 10 or rats castrated at birth and treated with TP during infancy. It was concluded that the masculine organization of systems and structures involved in the display of male copulatory behaviour occurs under the influence of both non-aromatizable androgen and oestrogen, oestrogen being most likely the substance required to 'organize' the central nervous aspects of the regulation of this behaviour. The absence neonatally of nonaromatizable androgen and/or oestrogen results in specific deficiencies in adult copulatory behaviour as compared with the behaviour of normal male rats.

Effects of arginine vasotocin, oxytocin, and arginine vasopressin on steroid-induced surges of luteinizing hormone and prolactin in ovariectomized rats

1980 ◽  
Vol 94 (2) ◽  
pp. 166-173 ◽  
Author(s):  
Ronald L. Salisbury ◽  
Richard J. Krieg ◽  
Hugo R. Seibel
Keyword(s):  
Luteinizing Hormone ◽  
Arginine Vasotocin ◽  
Ovariectomized Rats ◽  
Sprague Dawley ◽  
Lh Surge ◽  
Ovx Rats ◽  
Sprague Dawley Rats ◽  
Oestradiol Benzoate ◽  
Significant Augmentation ◽  
Low Levels

Abstract. Several studies have indicated that arginine vasotocin (AVT), a nonapeptide closely related to vasopressin (ADH) and oxytocin (OT), may act as a pineal antigonadotrophic factor. The present studies were designed to investigate the effects of AVT on the luteinizing hormone (LH) and prolactin (Prl) release induced by sequential steroid priming of ovariectomized (OVX). rats. Sprague-Dawley rats were used 6–8 weeks post-OVX. After implantation of an intra-atrial bleeding catheter, animals were primed with 5 μg of oestradiol benzoate (EB) at 08.00 h on the next morning. Forty-eight hours later 1.5 mg of progesterone (P) was injected and animals were divided into groups which received either saline, AVT (1 of 4 doses), ADH, or OT. The saline or peptides were infused via the intra-atrial catheter at 10.00, 11.00, 12.00, and 13.00 h. Hourly blood sampling was performed at 11.00–18.00 h, and at 21.00 h. The 11.00, 12.00, and 13.00 h samples were taken 10 min after saline or peptide infusion. LH and Prl responses to the peptide infusions could be divided into pre-surge and surge effects. AVT caused a slight, but significant elevation of the normally low levels of LH and Prl which occurred before the onset of their surges. Only the highest dose of AVT (1.0 μg) blocked the LH surge. ADH, however, was capable of stimulating LH and Prl release during the pre-surge period and of inhibiting the LH surge. AVT at a dose of 0.5 or 1.0 μg specifically blocked the onset of the Prl surge, causing Prl to drop to its lowest level at 14.00 h - the time at which Prl levels were maximal in saline-treated animals. After this initial inhibition, however, Prl levels rebounded to show a delayed surge. OT infusion, on the other hand, caused a significant augmentation of the Prl surge. These data indicate that AVT may specifically block the onset of the Prl surge seen after sequential steroid priming of OVX rats, while OT may facilitate the Prl surge.

CIRCADIAN RHYTHM OF PROLACTIN SURGES INDUCED BY STIMULATION OF THE UTERINE CERVIX IN THE OVARIECTOMIZED RAT: ITS SEXUAL DIFFERENTIATION AND PREOPTIC REGULATION

1981 ◽  
Vol 91 (2) ◽  
pp. 325-334 ◽  
Author(s):  
MASAZUMI KAWAKAMI ◽  
JUN ARITA
Keyword(s):  
Circadian Rhythm ◽  
Uterine Cervix ◽  
Testosterone Propionate ◽  
Neonatal Period ◽  
Female Rats ◽  
Male Rats ◽  
Ovariectomized Rats ◽  
Optic Chiasma ◽  
Bilateral Lesions ◽  
Stimulation Of

Stimulation of the uterine cervix (CS) induced a nocturnal surge of prolactin at 04.00 h and a diurnal surge at 17.00 h in normal ovariectomized rats. However, the CS-induced prolactin surges did not occur in ovariectomized rats which had been treated with 250 μg testosterone propionate during the neonatal period. Chronic bilateral lesions of the suprachiasmatic nucleus (SCN) completely abolished the CS-induced nocturnal and diurnal surges of prolactin release which were observed in sham-lesioned, ovariectomized rats. Furthermore, bilateral lesions of the medial basal part of the suprachiasmatic area (MBSC), lying rostral to the SCN, were also effective in blocking the CS-induced nocturnal and diurnal surges. Lesions which destroyed mainly the optic chiasma and extended partially into the MBSC and SCN did not block the CS-induced prolactin surges. These results suggest that one reason for the failure of ovary-grafted male rats and neonatally androgenized female rats to maintain pseudopregnancy is the extinction of the circadian rhythm of the two daily prolactin surges, and that the MBSC, in addition to the SCN which is known to be a generator of other circadian rhythms, is involved in generation of the rhythm of prolactin surges.

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