Hypothalamic areas involved in prostaglandin(PG) induced gonadotropin release. I. Effects of PGE2 and PGF(2α) implants on luteinizing hormone release

Sergio Ojeda, H. E. Jameson, S. M. McCann

Research output: Contribution to journalArticle

39 Citations (Scopus)

Abstract

Ovariectomized rats had a cannula inserted unilaterally within various hypothalamic areas. Several days later they were primed with a sc dose of 10 μg of estradiol benzoate (Eb). Two days after priming they were etherized and an initial blood sample was drawn from the external jugular vein. An inner cannula containing PGE2 or PGF(2α) at its tip was inserted into the previously implanted outer cannula. Blood samples were drawn at 20, 40, 60, and 120 min following the implantation. PGE2 induced a 4-5-fold increase in plasma LH 40 to 60 min following its implantation in the arcuate nucleus-median eminence region (ARH-ME). Levels were already significantly elevated at 20 min. When PGE2 was placed slightly more dorsally, close to the ventromedial nucleus (VMH), LH titers rose to comparable levels but only after a delay of 120 min. PGE2 implanted in the caudal portion of the ARH-ME or dorsally in the VMH-dorsomedial nuclei, barely increased plasma LH, whereas its placement in the anterior portion of the ARH-ME clearly elevated LH titers. PGE2 implants located more than 1 mm lateral from the midline or outside the hypothalamus were ineffective. When PGE2 was placed in the preoptic area (POA) or anterior ventral portion of the anterior hypothalamic area (AHA), plasma LH levels rose strikingly, the first significant increase being observed at 20 min. PGE2 implants located in the vicinity of the paraventricular nucleus-dorsal portion of AHA were much less effective. PGF(2α) implanted in the ARH-ME or POA induced a small increase in plasma LH and the implantation of empty cannulae in the same areas was ineffective. Intrapituitary implants of PGE2 failed to alter plasma LH significantly. The results indicate that PGE2 acts at the ARH-ME region to induce LH release and that an even more effective site of action seems to be located in the POA-AHA. Since these are areas which contain LHRH, the results support the view that PGs can activate LHRH-secreting neurons in these regions.

Original languageEnglish (US)
Pages (from-to)1585-1594
Number of pages10
JournalEndocrinology
Volume100
Issue number6
StatePublished - 1977
Externally publishedYes

Fingerprint

Prostaglandins F
Luteinizing Hormone
Gonadotropins
Dinoprostone
Prostaglandins
Anterior Hypothalamic Nucleus
Preoptic Area
Gonadotropin-Releasing Hormone
Mediodorsal Thalamic Nucleus
Median Eminence
Arcuate Nucleus of Hypothalamus
Paraventricular Hypothalamic Nucleus
Jugular Veins
Hypothalamus
Neurons
Cannula

ASJC Scopus subject areas

  • Endocrinology
  • Endocrinology, Diabetes and Metabolism

Cite this

Hypothalamic areas involved in prostaglandin(PG) induced gonadotropin release. I. Effects of PGE2 and PGF(2α) implants on luteinizing hormone release. / Ojeda, Sergio; Jameson, H. E.; McCann, S. M.

In: Endocrinology, Vol. 100, No. 6, 1977, p. 1585-1594.

Research output: Contribution to journalArticle

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