Pulsatile release of oxytocin into the circulation of the ewe during oestrus, mating and the early luteal phase

Gilbert, C.; Jenkins, Kirk; Wathes, D C

doi:10.1530/jrf.0.0910337

Cited by 34 publications

(21 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Such an experimental procedure is closer to conditions in vim, as evident from previous work demonstrating the rhythmic activity of oxytocinergic neurons in the paraventricular nucleus (46) and pulsatile release of OT into the circulation (47). However, the mechanism of rapid glucocorticoid inhibition on stimulated ACTH secretion is still unclear.…”

Section: Discussionmentioning

confidence: 85%

“…In addition, the short exposure (30 min) to corticosterone or glucocorticoid agonist and antagonist indicate the potency and specificity of the steroid effects on ACTH secretion due to pulsatile application of secretagogues. Such an experimental procedure is eloser to conditions in vivo, as evident from previous work demonstrating the rhythmic activity of oxytocinergic neurons in the paraventricular nueleus (46) and pulsatile release of OT into the circulation (47).…”

mentioning

confidence: 99%

See 1 more Smart Citation

Glucocorticoids rapidly inhibit oxytocin-stimulated adrenocorticotropin release from rat anterior pituitary cells, without modifying intracellular calcium transients.

1993

View full text Add to dashboard Cite

Glucocorticoid hormones suppress the secretion of ACTH evoked by secretagogues such as CRF and arginine vasopressin. In this study, we investigated the effects of glucocorticoids on ACTH release induced by oxytocin (OT) and on intracellular free calcium ion levels in corticotropes prepared from the adenohypophyses of female Wistar rats.Pulsatile additions of physiological concentration of OT (10 nM) to superfused anterior pituitary cells caused pulsatile ACTH release about 4-fold above basal secretion with similar peak amounts of ACTH du ring subsequent OT pulses. Exposure of the cells to corticosterone (100 nM) or to a selective glucocorticoid receptor agonist RU 28362 (100 nM) for 30 min suppressed OT-stimulated but not basal ACTH release by approximately 60%. Inhibition gradually disappeared during subsequent pulses of OT in the absence of corticosterone. Pretreatment with I

show abstract

Section: Discussionmentioning

confidence: 85%

mentioning

confidence: 99%

Glucocorticoids rapidly inhibit oxytocin-stimulated adrenocorticotropin release from rat anterior pituitary cells, without modifying intracellular calcium transients.

1993

View full text Add to dashboard Cite

show abstract

“…Oxytocin is also secreted into the blood during coitus in female goats (McNeilly & Ducker 1972), but there is an inconsistent increase in rabbits (Todd & Lightman 1986), and although oxytocin secretion in ewes increases in the presence of a ram, there is no further rise in secretion during mating itself (Gilbert et al 1991). Large doses of oxytocin given systemically facilitate lordosis in ovariectomised, oestrogen-primed rats.…”

Section: Sexual Activitymentioning

confidence: 99%

60 YEARS OF NEUROENDOCRINOLOGY: The posterior pituitary, from Geoffrey Harris to our present understanding

Leng¹,

Pineda²,

Sabatier³

et al. 2015

Journal of Endocrinology

View full text Add to dashboard Cite

Geoffrey Harris pioneered our understanding of the posterior pituitary, mainly with experiments that involved the electrical stimulation of the supraoptico-hypophysial tract. In the present essay, we explain how his observations included clues to the pulsatile nature of the oxytocin signal -clues that were followed up by subsequent workers, including his students and their students. These studies ultimately led to our present understanding of the milk-ejection reflex and of the role of oxytocin in parturition. Discoveries of wide significance followed, including: the recognition of the importance of pulsatile hormone secretion; the recognition of the importance of stimulus-secretion coupling mechanisms in interpreting the patterned electrical activity of neurons; the physiological importance of peptide release in the brain; the recognition that peptide release comes substantially from dendrites and can be regulated independently of nerve terminal secretion; and the importance of dynamic morphological changes to neuronal function in the hypothalamus. All of these discoveries followed from the drive to understand the milk-ejection reflex. We also reflect on Harris's observations on vasopressin secretion, on the effects of stress, and on oxytocin secretion during sexual activity.

show abstract

“…Receptors for oxytocin have been demonstrated in the non-pregnant uterus of human females and laboratory animals (Fuchs et al, 1985;Miller et al, 1993;Ivell et al, 1995). It has been shown that oxytocin is released from the posterior lobe of the pituitary gland in response to vaginal distension, in response to cervical stimulation and during intercourse in response to tactile as well as emotional stimuli (Fox et al, 1970;Fox and Fox, 1971;Fox, 1973;Fox, 1976;Gilbert et al, 1991;Murphy et al, 1987). In addition to its classic hypothalamic site of production, synthesis of oxytocin has also been demonstrated within the endometrium and the ovary respectively (Garcia Villar et al, 1983;Okuda et al, 1992;Ivell et al, 1995;Khan-Dawood et al, 1995).…”

Section: Normal and Disturbed Function Of The Uterus And Fallopian Tubesmentioning

confidence: 99%

Sperm transport in the human female genital tract and its modulation by oxytocin as assessed by hysterosalpingoscintigraphy, hysterotonography, electrohysterography and Doppler sonography

Wildt

Kissler²,

Licht³

et al. 1998

Human Reproduction Update

139

View full text Add to dashboard Cite

The transport function of the uterus and oviducts and its modulation by oxytocin has been examined using hysterosalpingoscintigraphy, recording of intrauterine pressure, electrohysterography and Doppler sonography of the Fallopian tubes. After application to the posterior vaginal fornix, a rapid (within minutes) uptake of the labelled particles into the uterus was observed during the follicular and during the luteal phase of the cycle in all patients. Transport into the oviducts, however, could only be demonstrated during the follicular phase. Transport was directed predominantly into the tube ipsilateral to the ovary bearing the dominant follicle; the contralateral oviduct appeared to be functionally closed. The proportion of patients exhibiting ipsilateral transport did increase concomitant with the increase of the diameter of the dominant follicle. That ipsilateral transport has biological significance is suggested by the observation that the pregnancy rate following spontaneous intercourse or insemination was significantly higher in those women in whom ipsilateral transport could be demonstrated than in those who failed to exhibit lateralization. Oxytocin administration was followed by a dramatic increase in the amount of material transported to the ipsilateral tube, as demonstrated by radionuclide imaging and by Doppler sonography following instillation of ultrasound contrast medium. Continuous recording of intrauterine pressure before and after oxytocin administration did show an increase in basal tonus and amplitude of contractions and a reversal of the pressure gradient from a fundo-cervical to a cervico-fundal direction. These actions of oxytocin were accompanied by an increase in amplitude of potentials recorded by electrohysterography. These data support the view that uterus and Fallopian tubes represent a functional unit that is acting as a peristaltic pump and that the increasing activity of this pump during the follicular phase of the menstrual cycle is reflected by an increased transport into the oviduct ipsilateral to the ovary bearing the dominant follicle. In addition, they strongly suggest a critical role of oxytocin in this process. Failure of this mechanism appears to be a cause of subfertility or infertility, as indicated by the low pregnancy rate following intrauterine insemination or normal intercourse in the presence of patent Fallopian tubes. It may be regarded as a new nosological entity for which we propose the term tubal transport disorder (TTD). Since pregnancy rate of such patients is normal when treated with in-vitro fertilization (IVF), hysterosalpingoscintigraphy seems to be useful for the choice of treatment modalities in patients with patent Fallopian tubes suffering from infertility.

show abstract

Pulsatile release of oxytocin into the circulation of the ewe during oestrus, mating and the early luteal phase

Cited by 34 publications

References 13 publications

Glucocorticoids rapidly inhibit oxytocin-stimulated adrenocorticotropin release from rat anterior pituitary cells, without modifying intracellular calcium transients.

Glucocorticoids rapidly inhibit oxytocin-stimulated adrenocorticotropin release from rat anterior pituitary cells, without modifying intracellular calcium transients.

60 YEARS OF NEUROENDOCRINOLOGY: The posterior pituitary, from Geoffrey Harris to our present understanding

Sperm transport in the human female genital tract and its modulation by oxytocin as assessed by hysterosalpingoscintigraphy, hysterotonography, electrohysterography and Doppler sonography

Contact Info

Product

Resources

About