Lead (Pb) alters the norepinephrine-induced secretion of luteinizing hormone releasing hormone from the median eminence of adult male rats in vitro

Journal Article · Sat Jan 01 04:00:00 EST 1994 · Life Sciences; (United States)

DOI:https://doi.org/10.1016/0024-3205(94)00482-X· OSTI ID:6786729

Bratton, G R; Hiney, J K; Dees, W L ^[1]

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1. Texas A M Univ., College Station, TX (United States)

In the present study, the authors evaluated the in vitro effects of lead (Pb) on basal and stimulated luteinizing hormone releasing hormone (LHRH) and Prostaglandin E[sub 2] (PGE[sub 2]) secretion. Median eminences (ME) were removed from brains of adult male rats and preincubated for 15 minutes in Krebs-Ringer bicarbonate glucose buffer in an atmosphere of 95% O[sub 2]-5% CO[sub 2]. These media were discarded and all MEs were subjected to one of the following experiments. In Experiment 1, all MEs were incubated for 30 minutes in medium only. These media were collected and replaced with medium only (controls) or with medium containing Pb doses ranging from 5 to 20 [mu]M. After this 60-minute incubation, media were collected, then replaced with new medium containing 60 [mu]M norepinephrine (NE), or NE plus each dose of Pb, then incubated for a final 30-minute period. Experiment 2 was conducted as above, except PGE[sub 2] (2.8 [mu]M) replaced the NE. In both experiments, the amounts of LHRH released was measured by RIA. In experiment 3, NE was again used for the challenge; however, this time, the amount of PGE[sub 2] released was measured by RIA. Results indicate that Pb did not alter basal LHRH release, but compared with controls, significantly blocked NE-induced LHRH release in a dose-related manner. Conversely, Pb had no effect on the PGE[sub 2]-induced release of LHRH. Additionally, Pb did not alter basal PGE[sub 2] release; however, it significantly blocked the NE-induced release of PGE[sub 2]. Since NE-induced LHRH release is mediated by PGE[sub 2], these results support the hypothesis that Pb is capable of altering the hypothalamus and suggest that this effect is due, at least in part, to the diminished PGE[sub 2] synthesis/release within the ME, resulting in diminished LHRH secretion.

• OSTI ID: 6786729
• Journal Information: Life Sciences; (United States), Journal Name: Life Sciences; (United States) Vol. 55:8; ISSN 0024-3205; ISSN LIFSAK
• Country of Publication: United States
• Language: English

Related Subjects

560300* -- Chemicals Metabolism & Toxicology
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ADRENAL HORMONES
AUTONOMIC NERVOUS SYSTEM AGENTS
BIOLOGICAL EFFECTS
BODY
BRAIN
CARDIOTONICS
CARDIOVASCULAR AGENTS
CENTRAL NERVOUS SYSTEM
DRUGS
ELEMENTS
HORMONES
HYPOTHALAMUS
LEAD
LH-RH
LIBERINS
METABOLISM
METALS
NERVOUS SYSTEM
NEUROREGULATORS
NORADRENALINE
ORGANIC COMPOUNDS
ORGANS
PEPTIDE HORMONES
PITUITARY HORMONES
PROSTAGLANDINS
PROTEINS
SECRETION
SYMPATHOMIMETICS