The Effect of Methionine Enkephalin on Prolactin and Luteinizing Hormone Levels in Intact and Castrated Rats

Rita Goldberg; N. Conforti; I. M. Spitz

doi:10.1055/s-2007-1018931

Hormone and Metabolic Research, Table of Contents

Horm Metab Res 1982; 14(2): 89-92
DOI: 10.1055/s-2007-1018931

The Effect of Methionine Enkephalin on Prolactin and Luteinizing Hormone Levels in Intact and Castrated Rats

Rita Goldberg¹ , N. Conforti² , I. M. Spitz¹

¹Department of Endocrinology and Metabolism, Shaare Zedek Medical Centre, Jerusalem, Israel
²Laboratory of Neurophysiology, Department of Neurology, Hebrew University Hadassah Medical School, Jerusalem, Israel

Abstract

PDF Download

Summary

The methionine enkephalin (ME) induced responses of prolactin (PRL) and luteinizing hormone (LH) were studied in control and castrated rats bearing chronically-implanted cannulae in the right lateral ventricle. In control rats, 500 μg ME caused a rise in PRL from a mean ± SD basal value of 22.8 ± 12.2 ng/ml to a peak of 195.2 ± 93.8 ng/ml (p < 0.001). The peak occurred 10 min after ME administration and was short-lived. In the same rats, 14 days after castration, there was a significant reduction in both basal (p < 0.001) and peak PRL response to ME (p < 0.01), similar to that previously observed with other PRL-inducing stimuli. LH levels, on the other hand, were unaffected by ME treatment in both control and castrated rats.

Key-Words:

Methionine Enkephalin - Prolactin - Luteinizing Hormone - Intact and Castrated Rats

PDF (371 kb)