Proliferative Capacity of the Hypophysial Portal Vessels

Harris, G. W.; Jacobsohn, Dora

doi:10.1038/165854a0

Cited by 23 publications

(9 citation statements)

References 2 publications

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“…Kanematsu & Sawyer (1973) showed elevated plasma PRL levels after the hypophyseal stalk was transected in the rat. These results showed that the neuroendocrine control of the pituitary hormones from the hypothalamus via the pituitary-portal system were dominantly controlled by stimulators, with the exception of PRL, which was regulated negatively by dopamine (Harris & Jacobsohn 1950, 1952, MacLeod 1969, Kanematsu & Sawyer 1973. Additionally, neuroendocrinological control of gonadotropin from the hypothalamus is maintained primarily via the stimulation associated with GnRH.…”

Section: Discussionmentioning

confidence: 70%

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Hypophysiotropic role of RFamide-related peptide-3 in the inhibition of LH secretion in female rats

Murakami¹,

Matsuzaki²,

Iwasa³

et al. 2008

Journal of Endocrinology

223

174

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Gonadotropin-inhibitory hormone (GnIH), a newly discovered hypothalamic RFamide peptide, inhibits reproductive activity by decreasing gonadotropin synthesis and release in birds. The gene of the mammalian RFamide-related peptides (RFRP) is orthologous to the GnIH gene. This Rfrp gene gives rise to the two biologically active peptides RFRP-1 (NPSF) and RFRP-3 (NPVF), and i.c.v. injections of RFRP-3 suppress LH secretion in several mammalian species. In this study, we show whether RFRP-3 affects LH secretion at the pituitary level and/or via the release of GnRH at the hypothalamus in mammals. To investigate the suppressive effects of RFRP-3 on the mean level of LH secretion and the frequency of pulsatile LH secretion in vivo, ovariectomized (OVX) mature rats were administered RFRP-3 using either i.c.v. or i.v. injections. Furthermore, the effect of RFRP-3 on LH secretion was also investigated using cultured female rat pituitary cells. With i.v. administrations, RFRP-3 significantly reduced plasma LH concentrations when compared with the physiological saline group. However, after i.c.v. RFRP-3 injections, neither the mean level of LH concentrations nor the frequency of the pulsatile LH secretion was affected. When using cultured pituitary cells, in the absence of GnRH, the suppressive effect of RFRP-3 on LH secretion was not clear, but when GnRH was present, RFRP-3 significantly suppressed LH secretion. These results suggest that RFRP-3 does not affect LH secretion via the release of GnRH, and that RFRP-3 directly acts upon the pituitary to suppress GnRH-stimulated LH secretion in female rats.

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Section: Discussionmentioning

confidence: 70%

“…In the classic study of Harris & Jacobsohn (1950, 1952, transplantation of the pituitary from the sella turcia to the renal capsule resulted in atrophy of the thyroid, the cortex of adrenal, and the gonad. Kanematsu & Sawyer (1973) showed elevated plasma PRL levels after the hypophyseal stalk was transected in the rat.…”

Section: Discussionmentioning

confidence: 99%

Hypophysiotropic role of RFamide-related peptide-3 in the inhibition of LH secretion in female rats

Murakami¹,

Matsuzaki²,

Iwasa³

et al. 2008

Journal of Endocrinology

223

174

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“…Transection of the pituitary stalk results in disruption of neuronal and circulatory connections between the hypothalamus and the pituitary in the rat. Neuronal damage is long lasting; diabetes insipidus is observable long after the transection, but there is a strong capacity of regeneration of the hypophysial portal vessels in the rat (25)(26)(27). This restored portal vessel connection also restores the regulation of anterior hypothalamic hormone secretions, thus GH secretion.…”

Section: Role Of Mbh In Neuroendocrine Regulation and In The Regulatimentioning

confidence: 86%

The anterolateral projections of the medial basal hypothalamus affect sleep

Péterfi¹,

Makara²,

Obál³

et al. 2009

American Journal of Physiology-Regulatory, Integrative and Comp

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Peterfi Z, Makara GB, Obál F Jr, Krueger JM. The anterolateral projections of the medial basal hypothalamus affect sleep. Am J Physiol Regul Integr Comp Physiol 296: R1228 -R1238, 2009. First published February 4, 2009 doi:10.1152/ajpregu.90958.2008-The role of the medial basal hypothalamus (MBH) and the anterior hypothalamus/preoptic area (AH/POA) in sleep regulation was investigated using the Halász knife technique to sever MBH anterior and lateral projections in rats. If both lateral and anterior connections of the MBH were cut, rats spent less time in non-rapid eye movement sleep (NREMS) and rapid eye movement sleep (REMS). In contrast, if the lateral connections remained intact, the duration of NREMS and REMS was normal. The diurnal rhythm of NREMS and REMS was altered in all groups except the sham control group. Changes in NREMS or REMS duration were not detected in a group with pituitary stalk lesions. Water consumption was enhanced in three groups of rats, possibly due to the lesion of vasopressin fibers entering the pituitary. EEG delta power during NREMS and brain temperatures (Tbr) were not affected by the cuts during baseline or after sleep deprivation. In response to 4 h of sleep deprivation, only one group, that with the most anterior-to-posterior cuts, failed to increase its NREMS or REMS time during the recovery sleep. After deprivation, Tbr returned to baseline in most of the treatment groups. Collectively, results indicate that the lateral projections of the MBH are important determinants of duration of NREMS and REMS, while more anterior projections are concerned with the diurnal distribution of sleep. Further, the MBH projections involved in sleep regulation are distinct from those involved in EEG delta activity, water intake, and brain temperature.anterior hypothalamus/preoptic area; sleep regulation; non-rapid eye movement sleep A RELATIONSHIP BETWEEN THE somatotropic axis and sleep was first recognized 40 years ago when the association between plasma growth hormone (GH) levels and non-rapid eye movement sleep (NREMS) was described by Takahashi et al. (77). Subsequently, much evidence has supported the hypothesis that hypothalamic growth hormone releasing hormone (GHRH) is involved in NREMS sleep regulation and, through its induction of pituitary release of GH, rapid eye movement sleep (REMS) as well (reviewed in Ref. 55). Within the hypothalamus, the majority of the GHRH-containing perikarya resides in the arcuate nucleus (ARC) (50,51,66). A smaller number of GHRH-containing neurons are found around the ventral border of the ventromedial nucleus, the dorsomedial nucleus, and in the parvocellular portion of the paraventricular nucleus (PVN), and the posterior hypothalamus. Previously, we showed that microinjection of GHRH into the medial preoptic region/anterior hypothalamus promotes NREMS, while injection of a GHRH antagonist peptide inhibited NREMS (80). The stimulated areas likely included the rostral portion of the periventricular (PeV) nucleus due to diffusion. Sites in the posterior...

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“…PHYSIOLOGICAL CONTROL SYSTEMS AND GOVERNING GONADAL FUNCTION passing through the roof of the mouth in order to perform a hypophysectomy without injuring the hypothalamus (reviewed by Anderson and Haymaker, 1974)! 50 After the second world war, Harris, using Smith's method for hypophysectomy, went on to show, first with Green 51,52 and then with Jacobsohn, 53,54 that the pituitary portal vessels acted as a "humoral relay" between the central nervous system and the anterior pituitary, that the direction of the portal circulation was brain-to-pituitary (confirming Wislocki's assumptions, 55 and refuting Popa and Fielding's) 56 and that the pituitaries, which were not themselves sexually differentiated, exerted their effects on the gonads only if the hypothalamo-hypophysial vascular connection was intact or had been reestablished. 47 Indeed, by 1936, van Dyke, in his Physiology and Pharmacology of the Pituitary Body, was able to list nine animal species and eight methods for hypophysectomizing them, and felt that Smith's method was the best.…”

Section: Introductionmentioning

confidence: 99%

Puberty in Mice and Rats

Prévot

2015

Knobil and Neill's Physiology of Reproduction

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Proliferative Capacity of the Hypophysial Portal Vessels

Cited by 23 publications

References 2 publications

Hypophysiotropic role of RFamide-related peptide-3 in the inhibition of LH secretion in female rats

Hypophysiotropic role of RFamide-related peptide-3 in the inhibition of LH secretion in female rats

The anterolateral projections of the medial basal hypothalamus affect sleep

Puberty in Mice and Rats

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