Title: CHANGES IN HYPOTHALAMIC PEPTIDASE ACTIVITY DURING THE OESTROUS CYCLE IN THE ADULT FEMALE RAT
Abstract: ABSTRACT The activity of peptidases in the rat hypothalamus which are capable of inactivating oxytocin has previously been found to vary with stimuli known to influence gonadotrophin release and may be related to both luteinizing hormone (LH) and luteinizing hormone releasing factor (LH-RF) release ( Griffith & Hooper 1972 a,b ). In the present study, enzyme activity was determined in normal female rats during the morning and afternoon of each stage of the oestrous cycle, in normal rats, and in female rats injected neonatally with testosterone. The activity of the supernatant fraction was found to be not significantly different during the morning of each stage, but was greatly decreased on the afternoon of pro-oestrus; particulate activity did not vary during the oestrous cycle. Supernatant and particulate activities were found to be the same in normal male rats and testosterone-treated females, as previously shown. Both fractions' activities were significantly less than those found in the oestrous cycle, other than on the afternoon of pro-oestrus. These results indicate changes in hypothalamic peptidase activity during the oestrous cycle which may be inversely related to LH and LH-RF release; they also confirm the masculinizing effect of neonatal testosterone on the hypothalamus.
Publication Year: 1973
Publication Date: 1973-09-01
Language: en
Type: article
Indexed In: ['crossref', 'pubmed']
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Cited By Count: 6
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