scholarly journals Prostaglandin F2a-Induced Prolactin Release and Luteolysis in the Goat

1979 ◽  
Vol 32 (1) ◽  
pp. 109 ◽  
Author(s):  
GR McMahon ◽  
RP Shearman ◽  
DA Shutt ◽  
I D Smith
Keyword(s):  
Luteal Phase ◽  
Late Gestation ◽  
Plasma Prolactin ◽  
Transient Effect ◽  
Prolactin Release ◽  
Plasma Progesterone ◽  
Prostaglandin F2a

Injection of prostaglandin F2? (PGF2 .) initiated a significant increase in plasma prolactin levels in all goats except those in anoestrus. Luteolysis occurred in non-pregnant goats during the mid luteal phase when the goats were given PGF2? either with Or without the suppression of prolactin release by bromocryptine (CB154). Luteolysis and subsequent parturition also occurred in pregnant goats in mid and late gestation after PGF2? injection, with an associated release of prolactin and decrease in plasma progesterone. Acute prolactin release in response to injection of thyrotrophin releasing factor may have had a transient effect on plasma progesterone levels, but did not appear to be luteolytic in either pregnant or non-pregnant goats.

Changes in the gene expression of progesterone receptor and prolactin receptor in sow mammary gland between late gestation and lactation

1998 ◽  
Vol 1998 ◽  
pp. 179-179
Author(s):  
H. M. Miller ◽  
W. T. Dixon ◽  
G. R. Foxcroft ◽  
F. X. Aherne
Keyword(s):  
Progesterone Receptor ◽  
Prolactin Receptor ◽  
Plasma Concentrations ◽  
Progesterone Receptors ◽  
Late Gestation ◽  
Rapid Decline ◽  
Plasma Prolactin ◽  
Early Lactation ◽  
Plasma Progesterone ◽  
Receptor Mrna

Lactogenesis is triggered by a rapid decline in plasma progesterone concentration combined with a peak in plasma prolactin concentration; in mice, there is a concurrent loss of mammary progesterone receptors (Haslam and Shyamala, 1980). The aims of this experiment were to determine the pattern of change of progesterone receptor and prolactin receptor mRNA during late gestation and early lactation and to determine whether abundance of mRNA for the two receptors are related to each other, to plasma concentrations of progesterone and prolactin or to piglet performance.

Changes in the gene expression of progesterone receptor and prolactin receptor in sow mammary gland between late gestation and lactation

1998 ◽  
Vol 1998 ◽  
pp. 179-179
Author(s):  
H. M. Miller ◽  
W. T. Dixon ◽  
G. R. Foxcroft ◽  
F. X. Aherne
Keyword(s):  
Progesterone Receptor ◽  
Prolactin Receptor ◽  
Plasma Concentrations ◽  
Progesterone Receptors ◽  
Late Gestation ◽  
Rapid Decline ◽  
Plasma Prolactin ◽  
Early Lactation ◽  
Plasma Progesterone ◽  
Receptor Mrna

Lactogenesis is triggered by a rapid decline in plasma progesterone concentration combined with a peak in plasma prolactin concentration; in mice, there is a concurrent loss of mammary progesterone receptors (Haslam and Shyamala, 1980). The aims of this experiment were to determine the pattern of change of progesterone receptor and prolactin receptor mRNA during late gestation and early lactation and to determine whether abundance of mRNA for the two receptors are related to each other, to plasma concentrations of progesterone and prolactin or to piglet performance.

EFFECT OF LOW ZINC INTAKE DURING PREGNANCY ON PLASMA PROLACTIN, PROGESTERONE, PROSTAGLANDIN, CORTISOL AND PROTEIN CONCENTRATIONS OF EWES DURING THE PERIPARTURIENT PERIOD

1986 ◽  
Vol 66 (3) ◽  
pp. 643-651 ◽  
Author(s):  
J. A. FITZGERALD ◽  
G. A. EVERETT ◽  
J. APGAR
Keyword(s):  
Plasma Concentrations ◽  
Normal Pregnancy ◽  
Late Gestation ◽  
Plasma Prolactin ◽  
Plasma Parameters ◽  
Zinc Intake ◽  
Periparturient Period ◽  
Prostaglandin F ◽  
The Mean ◽  
Pregnant Ewe

The effect of low dietary Zn intake upon several plasma endocrine and metabolic profiles was examined during late gestation in the ewe. Thirty adult, primiparous Finncross ewes were fed a low Zn diet with (+Zn, n = 14) or without (0Zn, n = 16) supplemental Zn in the drinking water starting day 1 of pregnancy. Although the mean prepartum progesterone and prolactin concentrations were lower (P < 0.05 and P < 0.01, respectively) in 0Zn than in +Zn ewes, the peak prolactin concentrations in 0Zn ewes at lambing were similar to +Zn ewes. Both basal and thyrotropin-releasing-hormone (TRH)-induced prolactin release were less (P < 0.01) in 0Zn ewes 2 d postpartum. Plasma concentrations of 13, 14-dihydro-15-keto prostaglandin F2α (PGFM) of ewes sampled within 45 min post-lambing were lower (P < 0.05) in 0Zn ewes. There was no difference in cortisol concentrations within 45 min after lambing between 0Zn and + Zn ewes. Plasma protein concentrations in 0Zn ewes were higher (P < 0.01) than those in +Zn ewes during pregnancy. In summary, these data show that low Zn intake in the pregnant ewe affected several endocrine and metabolic plasma parameters associated with normal pregnancy and parturition. Key words: Zinc, parturition, dystocia, feed intake, ovine

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 Changes in prolactin secretion in the short- and long-term after adrenalectomy

2012 ◽  
Vol 56 (4) ◽  
pp. 244-249 ◽  
Author(s):  
Maria Thereza C. Laguna-Abreu ◽  
Carla Germano ◽  
Ayrton C. Moreira ◽  
José Antunes-Rodrigues ◽  
Lucila Elias ◽  
...  
Keyword(s):  
Hpa Axis ◽  
Plasma Corticosterone ◽  
Prolactin Secretion ◽  
Plasma Prolactin ◽  
Peptidergic Neurons ◽  
Prolactin Release ◽  
Short And Long Term ◽  
Hypothalamus Pituitary Adrenal Axis ◽  
Pituitary Adrenal Axis

OBJECTIVE: To evaluate the modulation of the hypothalamus-pituitary-adrenal axis (HPA) on prolactin secretion in rats after adrenalectomy (ADX). MATERIALS AND METHODS: Plasma corticosterone, ACTH, and prolactin concentrations were measured by radioimmunoassay in rats after bilateral ADX in the short- (3 hours and 1day) and long-term (3, 7, and 14 days). RESULTS: Animals that underwent ADX showed undetectable corticosterone levels and a triphasic ACTH response with a transient increase (3h), a decrease (1d), and further increase in the long-term after ADX. Sham animals showed a marked increase in corticosterone and ACTH levels three hours after surgery, with a decrease to basal levels thereafter. Plasma prolactin levels were not changed after ADX. CONCLUSION: There are different points of equilibrium in the HPA axis after the glucocorticoid negative feedback is removed. Prolactin plasma secretion is not altered in the short or long- term after ADX, suggesting that the peptidergic neurons essential for prolactin release are not activated after ADX.

The use of salivary progesterone assays in the assessment of ovarian function in postmenarcheal girls

1984 ◽  
Vol 102 (2) ◽  
pp. 265-268 ◽  
Author(s):  
G. F. Read ◽  
D. W. Wilson ◽  
I. A. Hughes ◽  
K. Griffiths
Keyword(s):  
Luteal Phase ◽  
Ovarian Function ◽  
Age Groups ◽  
Premenopausal Women ◽  
Chronological Age ◽  
First Year ◽  
Published Data ◽  
Sufficient Data ◽  
Plasma Progesterone ◽  
Probable Occurrence

ABSTRACT Menstrual cycle profiles of salivary progesterone were derived from daily samples obtained from 75 postmenarcheal girls aged between 12 and 17 years. Data were analysed to establish the proportion of girls exhibiting ovulatory cycles in each of several age groups following menarche or in groups based solely on chronological age. 'Luteal'-phase profiles of salivary progesterone, which were similar in shape to those characteristic of mature premenopausal women, were taken to indicate the probable occurrence of ovulation. The percentage of cycles in those subjects judged to be ovulatory, grouped according to gynaecological age, rose from 14% in the first year to 56% in the fourth year. Those classified according to chronological age, and where sufficient data permitted reliable estimates of the percentage of subjects ovulating, rose from 11% at 12 years of age to 64% for girls aged 16. These data are in reasonable concordance with published data using plasma progesterone and urinary methods for establishing ovulatory incidence, and indicate the value of salivary progesterone measurements in studies of ovarian function in adolescence. J. Endocr. (1984) 102, 265–268

Decreased thermal conductance during the luteal phase of the menstrual cycle in women

1990 ◽  
Vol 69 (6) ◽  
pp. 2029-2033 ◽  
Author(s):  
P. Frascarolo ◽  
Y. Schutz ◽  
E. Jequier
Keyword(s):  
Menstrual Cycle ◽  
Thermal Equilibrium ◽  
Luteal Phase ◽  
Thermal Conductance ◽  
Heat Losses ◽  
Tympanic Temperature ◽  
Whole Body ◽  
Direct Calorimetry ◽  
Plasma Progesterone ◽  
Metabolic Heat

To study the influence of the menstrual cycle on whole body thermal balance and on thermoregulatory mechanisms, metabolic heat production (M) was measured by indirect calorimetry and total heat losses (H) were measured by direct calorimetry in nine women during the follicular (F) and the luteal (L) phases of the menstrual cycle. The subjects were studied while exposed for 90 min to neutral environmental conditions (ambient temperature 28 degrees C, relative humidity 40%) in a direct calorimeter. The values of M and H were not modified by the phase of the menstrual cycle. Furthermore, in both phases the subjects were in thermal equilibrium because M was similar to H (69.7 +/- 1.8 and 72.1 +/- 1.8 W in F and 70.4 +/- 1.9 and 71.4 +/- 1.7 W in L phases, respectively). Tympanic temperature (Tty) was 0.24 +/- 0.07 degrees C higher in the L than in the F phase (P less than 0.05), whereas mean skin temperature (Tsk) was unchanged. Calculated skin thermal conductance (Ksk) was lower in the L (17.9 +/- 0.6 W.m-2.degrees C-1) than in the F phase (20.1 +/- 1.1 W.m-2.degrees C-1; P less than 0.05). Calculated skin blood flow (Fsk) was also lower in the L (0.101 +/- 0.008 l.min-1.m-2) than in the F phase (0.131 +/- 0.015 l.min-1.m-2; P less than 0.05). Differences in Tty, Ksk, and Fsk were not correlated with changes in plasma progesterone concentration. It is concluded that, during the L phase, a decreased thermal conductance in women exposed to a neutral environment allows the maintenance of a higher internal temperature.

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