PLASMA PROLACTIN AND PROGESTERONE RESPONSES TO MATING ARE ALTERED IN AGED RATS

1981 ◽  
Vol 90 (2) ◽  
pp. 179-191 ◽  
Author(s):  
S. HENDRICKS ◽  
C. A. BLAKE
Keyword(s):  
Plasma Concentrations ◽  
External Jugular Vein ◽  
Female Rats ◽  
Plasma Prolactin ◽  
Aged Rats ◽  
Pregnant Rats ◽  
Pregnant Rat ◽  
Plasma Progesterone ◽  
The One ◽  
The Right

The effects of varying amounts of copulatory stimulation on patterns of plasma concentrations of prolactin and progesterone were evaluated in 3- and 12-month-old female rats. The 12-month-old group included rats which still exhibited oestrous cycles and rats in persistent vaginal oestrus (PVO). The extent of copulatory stimulation was defined by the number of intromissions received during mating: ≤5,15 or > 50. Blood samples were drawn over the 8 days after mating through a cannula inserted into the right external jugular vein. Plasma from the samples was assayed for prolactin and progesterone. In aged but still cyclic rats, pregnancy rates were positively correlated with the number of intromissions received during mating. Only one rat in PVO became pregnant. All animals which became pregnant and rats in PVO which, after mating, exhibited a disruption of the pattern of PVO, showed the nocturnal surge of plasma prolactin characteristic of pregnant and pseudopregnant rats. While these surges persisted until day 8 after mating in pregnant animals, they were absent by this time in the rats in PVO. Prolactin surges were present in some but not all of the aged rats which did not become pregnant. Progesterone concentrations were raised in all pregnant animals except the one pregnant rat in PVO and, while not related to the number of intromissions, concentrations were higher 8 days after mating in young compared with those in aged pregnant rats. Plasma progesterone was low in rats in PVO regardless of disruption of the pattern of PVO. We have concluded that the failure of limited copulatory stimulation to induce pregnancy in older rats results, at least in part, from its failure to initiate nocturnal prolactin surges. Nevertheless, our data suggest that matings which are not experimentally limited should provide ample stimulation to establish such surges. Although reduced plasma concentrations of prolactin and progesterone at pro-oestrus and reduced plasma progesterone through part of gestation may contribute to decreasing fertility in aged rats, other unidentified factors appear to be involved in mediating the capacity of extensive copulatory stimulation to induce pregnancy in these animals.

scholarly journals Age-Related Effects on Right Femoral Bone of Male Wistar Rats: A Morphometric and Biomechanical Study

2021 ◽  
Author(s):  
Sheila Martins Puelker ◽  
Sonia Regina Ribeiro de Castro ◽  
Romeu Rodrigues de Souza ◽  
Laura Beatriz Mesiano Maifrino ◽  
Ricardo Aparecido Baptista Nucci ◽  
...  
Keyword(s):  
Cortical Thickness ◽  
Wistar Rats ◽  
Female Rats ◽  
Male Rats ◽  
Aged Rats ◽  
Femoral Bone ◽  
Middle Aged ◽  
Left Femur ◽  
Bone Stiffness ◽  
The Right

Abstract Introduction Study of the variations of bone characteristics with age in different animal models is important to design musculoskeletal studies. Thus, this study aimed to evaluate the bone mass, dimensions, and biomechanical parameters of the femur in young, middle-aged, and aged Wistar rats. Materials and Methods Thirty male rats (Rattus norvegicus) were divided in three groups (n = 10 per group)—3-month-old young rats, 12-month-old middle-aged rats, and 18-months-old aged rats. The right femurs were subjected sequentially to morphometric study (bone weight, cortical thickness) and biomechanical tests (maximum resistance strength and bone stiffness). Results We observed a significant increase in femur histological (cortical thickness) and biomechanical (maximum strength and bone stiffness) parameters with aging when compared with young animals. Conclusions With the advancing age, the right femoral bone of middle-aged and old animals had greater variations when compared with young animals. However, further studies with the aid of a comparison between right and left femur and other long bones in both male and female rats are needed to corroborate with our findings.

Prenatal exposure to ethanol causes partial diabetes insipidus in adult rats

2004 ◽  
Vol 287 (2) ◽  
pp. R277-R283 ◽  
Author(s):  
Daniel S. Knee ◽  
Aileen K. Sato ◽  
Catherine F. T. Uyehara ◽  
John R. Claybaugh
Keyword(s):  
Diabetes Insipidus ◽  
Water Intake ◽  
Plasma Osmolality ◽  
Liquid Diet ◽  
Female Rats ◽  
Adult Rats ◽  
Pregnant Rats ◽  
Adult Rat ◽  
Mrna Content ◽  
The Right

Chronic consumption of ethanol in adult rats and humans leads to reduced AVP-producing neurons, and prenatal ethanol (PE) exposure has been reported to cause changes in the morphology of AVP-producing cells in the suprachiasmatic nucleus of young rats. The present studies further characterize the effects of PE exposure on AVP in the young adult rat, its hypothalamic synthesis, pituitary storage, and osmotically stimulated release. Pregnant rats were fed a liquid diet with 35% of the calories from ethanol or a control liquid diet for days 7–22 of pregnancy. Water consumption and urine excretion rate were measured in the offspring at 60–68 days of age. Subsequently, the offspring were infused with 5% NaCl at 0.05 ml·kg−1·min−1 with plasma samples taken before and at three 40-min intervals during infusion for measurement of AVP and osmolality. Urine output and water intake were ∼20% greater in PE-exposed rats than in rats with no PE exposure, and female rats had a greater water intake than males. The relationship between plasma osmolality and AVP in PE-exposed rats was parallel to, but shifted to the right of, the control rats, indicating an increase in osmotic threshold for AVP release. Pituitary AVP was reduced by 13% and hypothalamic AVP mRNA content was reduced by 35% in PE-exposed rats. Our data suggest that PE exposure can cause a permanent condition of a mild partial central diabetes insipidus.

EFFECTS OF PINEALECTOMY AND CONSTANT LIGHT AND DARKNESS ON PROLACTIN LEVELS IN THE PITUITARY AND PLASMA AND ON PITUITARY ULTRASTRUCTURE OF THE RAT

1972 ◽  
Vol 54 (2) ◽  
pp. 263-NP ◽  
Author(s):  
R. RELKIN ◽  
M. ADACHI ◽  
S. A. KAHAN
Keyword(s):  
Plasma Concentrations ◽  
Virgin Female ◽  
Female Rats ◽  
Constant Light ◽  
Constant Darkness ◽  
Plasma Prolactin ◽  
Continuous Darkness ◽  
Prolactin Content ◽  
Intermediate Degree ◽  
Pituitary Prolactin

SUMMARY The effects of constant light, constant darkness and diurnal lighting, in combination with pinealectomy or sham-pinealectomy, on pituitary and plasma concentrations of radioimmunoassayable prolactin were investigated in 8-week-old male and virgin female rats. Two to three days after operation random groups of pinealectomized and sham-pinealectomized animals of the same sex were placed together in either continous light, continuous darkness or diurnal light, and killed 21 days later. Compared with sham-operated diurnally-illuminated controls, constant darkness caused a decrease in pituitary prolactin content and a rise in plasma prolactin levels. Pinealectomy or constant illumination reversed the effect of constant darkness, resulting in an increase in pituitary prolactin content and a fall in plasma prolactin levels when compared with sham-operated diurnally-illuminated controls. Electron microscopy of lactotrophic cells of the sham-pinealectomized animals exposed to constant darkness revealed few cytoplasmic granules, whereas these cells in the sham-pinealectomized animals exposed to constant light contained abundant granules; compared with the former groups, lactotrophic cells of sham-pinealectomized rats exposed to diurnal lighting revealed an intermediate degree of granulation.

scholarly journals Intracerebroventricular administration of the prolactin (PRL) receptor antagonist, S179D PRL, disrupts parturition in rats

Reproduction ◽  
2007 ◽  
Vol 134 (1) ◽  
pp. 155-160 ◽  
Author(s):  
B C Nephew ◽  
J Amico ◽  
H M Cai ◽  
A M Walker ◽  
R S Bridges
Keyword(s):  
Receptor Antagonist ◽  
Plasma Concentrations ◽  
Female Rats ◽  
Plasma Progesterone ◽  
Blood Samples ◽  
Period Effects ◽  
Preliminary Study ◽  
Nulliparous Female ◽  
Plasma Prl

The prolactin (PRL) receptor antagonist S179D PRL delays the onset of maternal behavior in steroid-primed nulliparous female rats. The present study investigated the role of the neural PRL system in the process of parturition. A preliminary study indicated that S179D PRL treatments administered by ALZET minipump to the lateral ventricle severely disrupted parturition. To examine the likely causes of this disruption, a group of timed-pregnant catheterized rats was continuously infused with S-179D PRL (0.001 and 0.1 ng/h) or vehicle control to the lateral ventricles for 3 days (gestation days 21–23), and serial blood samples were taken throughout this period. Effects of the treatments on parturition were recorded, and blood samples were assayed for PRL, progesterone, and oxytocin. Significantly fewer S179D PRL-treated rats successfully delivered by 1500 h on day 23 of gestation when compared with controls. The higher dose of S179D PRL also significantly suppressed the prepartum rise in PRL throughout the prepartum period, while the lower dose only affected plasma PRL during the first 24 h of treatment. No significant effects of the antagonist on plasma progesterone or oxytocin were detected. We conclude that disruption of parturition by S179D PRL is not caused by significant alterations in the plasma concentrations of progesterone or oxytocin. S179D PRL may indirectly act on parturition through the modulation of prepartum PRL. These findings suggest a previously unrecognized role for PRL in the regulation of parturition.

A COMPARISON OF THE CONCENTRATION OF C14 IN THE TISSUES OF PREGNANT AND NONPREGNANT FEMALE RATS FOLLOWING THE INTRAVENOUS ADMINISTRATION OF VITAMIN K1-C14 AND VITAMIN K3-C14

1957 ◽  
Vol 35 (1) ◽  
pp. 691-697 ◽  
Author(s):  
J. D. Taylor ◽  
G. J. Millar ◽  
R. J. Wood
Keyword(s):  
Skeletal Muscle ◽  
Vitamin K ◽  
Intravenous Administration ◽  
Fetal Liver ◽  
Live Weight ◽  
Fetal Tissue ◽  
Female Rats ◽  
Pregnant Rats ◽  
Pregnant Rat ◽  
Significant Difference

The C14 content was determined of the livers, spleens, skeletal muscle, blood, feces, and urine of both pregnant and nonpregnant female rats and of the placentas, fetal livers, fetuses, and amnionic fluids of pregnant rats following the intravenous administration of 5 mg./kg. of either vitamin K1-C14 or vitamin K3-C14. The C14 concentrations of the livers of the rats given vitamin Kt were about 24 times larger than those of animals that had received vitamin K3-C14. A fivefold difference in the same direction exists between the concentrations in the spleens of the two groups. The C14 levels for skeletal muscle, blood, placenta, fetal liver, and fetal tissue were of similar magnitude regardless of whether vitamin Kt or vitamin K3 was administered. Isotope dilution tests revealed that following intravenous administration of vitamin K1-C14 the amount of radioactivity present as unchanged vitamin Kt-C14 was 12% for fetal tissue, 59% for placenta, and 120% for the maternal liver. The dry weights of the livers of pregnant rats were larger than those of nonpregnant rats and the increase was proportional to the live weight of the pregnant rat. No significant difference could be demonstrated in the percentage of the injected dose of vitamin K1 deposited in the livers of pregnant or nonpregnant rats. The same was true for vitamin K3-C14. The results of this experiment indicate that vitamin K3-C14 is not concentrated in the liver of the rat whereas vitamin K1-C14 is. Furthermore, it would appear that both vitamin K1 and vitamin K3 can pass the placental barrier of the rat.

scholarly journals Plasma Formate Is Greater in Fetal and Neonatal Rats Compared with Their Mothers

2020 ◽  
Vol 150 (5) ◽  
pp. 1068-1075 ◽  
Author(s):  
Margaret E Brosnan ◽  
Garrett Tingley ◽  
Luke MacMillan ◽  
Brian Harnett ◽  
Theerawat Pongnopparat ◽  
...  
Keyword(s):  
Virgin Female ◽  
Female Rats ◽  
Neonatal Rats ◽  
Adult Rats ◽  
Pregnant Rats ◽  
Highly Active ◽  
Expression Of Genes ◽  
Methylenetetrahydrofolate Dehydrogenase ◽  
Glycine Cleavage ◽  
The One

ABSTRACT Background Formate can be incorporated into 10-formyl-tetrahydrofolate (10-formyl-THF), which is a substrate for purine synthesis, and after further reduction of the one-carbon group, may be used as a substrate for thymidylate synthesis and for homocysteine remethylation. Objective We examined plasma formate concentrations and the expression of genes involved in the production and utilization of formate in fetal and neonatal rats and in pregnant and virgin female rats. Methods In 1 experiment, plasma formate was measured by GC-MS in rats aged 1–56 d. In a second experiment, virgin female (adult) rats, 19-d pregnant rats (P) and their male and female fetuses (F), and 3-d-old (N) and 7-d-old (J) offspring had plasma and amniotic fluid analyzed for formate by GC-MS, mRNA abundance in liver and placenta by qPCR, and several plasma amino acids by HPLC. Results The plasma formate concentration was significantly higher in fetuses at embryonic day 19 than in the mothers. It was also significantly higher in neonatal rats but slowly returned to adult concentrations by ∼3 wk. The abundance of mitochondrial monofunctional 10-formyl-tetrahydrofolate synthetase (Mthfd1l) mRNA was significantly higher in placenta (PP) and F liver than in liver of N or J. Expression of mitochondrial bifunctional NAD-dependent methylene-tetrahydrofolate dehydrogenase/methenyl-tetrahydrofolate cyclohydrolase (Mthfd2) was significantly enriched in PP and liver of P, intermediate in F liver, and much lower in liver of N and J, relative to PP. Serine hydroxymethyltransferase 2 (Shmt2), methylenetetrahydrofolate dehydrogenase 1 (Mthfd1), and glycine decarboxylase protein of the glycine cleavage system (Gldc) mRNA expression was significantly lower in PP compared with other groups. Cytoplasmic NAD(P)-dependent 10-formyl-tetrahydrofolate dehydrogenase (Aldh1/1) and mitochondrial NAD(P)-dependent 10-formyl-tetrahydrofolate dehydrogenase (Aldh1/2) , genes responsible for the catabolism of 10-formylTHF, were very weakly expressed in PP, low in livers of F and N, and reached the significantly higher adult levels in J. Serine, glycine, and methionine concentrations in plasma of F were significantly higher than in plasma of P. Conclusions Formate metabolism is highly active in fetuses and in placenta of pregnant rats.

Effects of antiserum to thyrotrophin-releasing hormone on the concentrations of plasma prolactin, thyrotrophin and LH in the pro-oestrous rat

1985 ◽  
Vol 104 (2) ◽  
pp. 205-209 ◽  
Author(s):  
A. M. Horn ◽  
H. M. Fraser ◽  
G. Fink
Keyword(s):  
Plasma Concentrations ◽  
Passive Immunization ◽  
Immune Serum ◽  
Female Rats ◽  
Plasma Prolactin ◽  
Thyrotrophin Releasing Hormone ◽  
Blood Samples ◽  
Releasing Hormone ◽  
Sheep Blood

ABSTRACT The possible role of thyrotrophin-releasing hormone (TRH) in causing the pro-oestrous surge of prolactin was investigated in conscious female rats by passive immunization with a specific anti-TRH serum raised in sheep. Blood samples were withdrawn through a previously implanted intra-atrial cannula. The i.p. injection of 1 ml anti-TRH serum, but not non-immune sheep serum, at 13.00 h of pro-oestrus delayed by about 1 h the onset of the prolactin surge, but the peak of the surge was similar to that in animals injected with the non-immune serum. The plasma concentrations of TSH were significantly reduced by the anti-TRH serum, but plasma concentrations of LH were not significantly affected. These results show that TRH may play an important role in the timing and initiation, but not the maintenance of the prolactin surge in the pro-oestrous rat. J. Endocr. (1985) 104, 205–209

LEVELS OF α-MELANOTROPHIN IN THE PLASMA AND PITUITARY GLANDS OF FETAL AND JUVENILE RATS, AND IN THE PLASMA OF ADULT FEMALE RATS DURING PREGNANCY AND LACTATION

1980 ◽  
Vol 84 (3) ◽  
pp. 363-370 ◽  
Author(s):  
J. F. WILSON ◽  
MERRILL A. MORGAN
Keyword(s):  
Plasma Concentrations ◽  
Postnatal Period ◽  
Female Rats ◽  
Pregnant Rats ◽  
Juvenile Rats ◽  
Stress Effects ◽  
Fetal Rats ◽  
Pregnancy And Lactation ◽  
Pituitary Glands ◽  
Reproductive Processes

α-Melanotrophin was detected by radioimmunoassay in the pituitary glands of fetal rats from day 17 of gestation. The pituitary content of α-melanotrophin increased regularly, at a gradually decreasing rate, throughout gestation and in the postnatal period. Concentrations of α-melanotrophin in the plasma of fetal and newborn rats were below the detection limit of the radioimmunoassay (10 pmol/l). Detectable concentrations were first found in young rats on day 3 after birth and did not differ significantly from those in their mothers throughout the period of suckling. Plasma concentrations of α-melanotrophin were raised in pregnant rats during the last 4 days of gestation and after parturition. They returned to basal levels in the 2 weeks after delivery. After weaning at 3 weeks of age, a large increase in the plasma concentration of α-melanotrophin was detected in juvenile rats. Plasma levels had returned to the normal adult range by 6 weeks of age. The increases in α-melanotrophin in the blood were thought to be the result of non-specific stress effects. The data did not provide evidence for a role for α-melanotrophin in reproductive processes in the rat.

Regulation in pregnant mink (Mustela vison) of plasma progesterone and prolactin concentrations and regulation of onset of the spring moult by daylight ratio and melatonin injections

1983 ◽  
Vol 61 (9) ◽  
pp. 1959-1963 ◽  
Author(s):  
L. Martinet ◽  
D. Allain ◽  
M. Meunier
Keyword(s):  
Prolactin Secretion ◽  
The Other ◽  
Short Photoperiod ◽  
Plasma Prolactin ◽  
Positive Relation ◽  
Vernal Equinox ◽  
Plasma Progesterone ◽  
Progesterone Secretion ◽  
The One ◽  
L 13

In pregnant or pseudopregnant mink maintained under natural daylight conditions and mated early in March, plasma prolactin and progesterone levels began to increase after the vernal equinox. The onset of spring moult was observed a few days later. When the females were transferred to a 15 h light (L): 9 h dark (D) photoperiod just after mating, prolactin and progesterone increase was advanced by several days; when the mink were transferred to an 11 h L: 13 h D schedule, these increases, as well as the onset of spring moult, were delayed or inhibited. A daily afternoon injection of melatonin mimicked the effects of short photoperiod. A positive relation was observed between plasma prolactin on the one hand and progesterone secretion or onset of moulting on the other. These results suggest that short photoperiod or melatonin effects might act by inhibiting prolactin secretion.

Vasorelaxation and vascular binding sites for atrial natriuretic peptide in pregnant rats

1988 ◽  
Vol 254 (6) ◽  
pp. H1027-H1033
Author(s):  
J. St-Louis ◽  
A. Parent ◽  
J. Gutkowska ◽  
J. Genest ◽  
E. L. Schiffrin
Keyword(s):  
Atrial Natriuretic Peptide ◽  
Natriuretic Peptide ◽  
Binding Sites ◽  
Female Rats ◽  
Pregnant Rats ◽  
Binding Characteristics ◽  
Vascular Bed ◽  
Mesenteric Vascular Bed ◽  
The Right ◽  
Atrial Natriuretic

To investigate the role of atrial natriuretic peptide (ANP) in pregnancy, we measured, in cyclic and pregnant female rats (9- and 21-days pregnant), the vascular responsiveness to ANP using helical strips of the thoracic aorta, the binding characteristics of 125I-labeled ANP in a membrane preparation of the mesenteric vascular bed, and the plasma level and the atrial content of immunoreactive ANP (IR-ANP). On aorta strips, concentration-response (C-R) curves to phenylephrine (PE) were measured and were slightly displaced to the right in the aorta of both groups of pregnant rats in comparison with the cyclic rats. There was a potentiation of the relaxant response of ANP on the PE-precontracted aortic strips of 9-day pregnant rats but it was not statistically modified in tissues of 21-day pregnant rats in comparison with strips from cyclic rats. The number of binding sites (Bmax) for ANP in the mesenteric vascular bed was similar in cyclic rats and the two groups of pregnant rats. The dissociation constant (KD) of ANP was lower in 9-day pregnant rats than in cyclic and 21-day pregnant ones. Plasma IR-ANP was not different in 9-day pregnant rats and cyclic rats but was markedly decreased at the end of gestation. Atrial content of IR-ANP increased at the end of gestation, but not in midpregnancy in comparison with cyclic rats. These results indicate that despite the reported important increase in blood volume during gestation the secretion of ANP is not increased and suggest that the ANP-volume relationship is reset during pregnancy in the rat.

Sign in / Sign up

Export Citation Format

Share Document