Abstract
Age-related changes in hypothalamic luteinizing hormone-releasing hormone (LHRH) and luteinizing hormone (LH) secretion were studied in young (6 months), middle-aged (12 months) and old (18 months) female rats. The LHRH levels in the mid-hypothalamic area were higher in intact middle-aged and old females than in young ones. Additionally, there was no age difference in the hypothalamic LHRH levels in male rats. In order to clarify the significance of this age-related increase in female rats, we examined the effects of progesterone treatment in estrogen-primed ovariectomized young and old rats on the LHRH levels in the median eminence (ME) and on plasma LH levels. We found phasic changes in ME-LHRH and plasma LH levels in estrogen-primed rats following progesterone treatment in rats of both ages, but the progesterone-induced change in ME-LHRH levels tended to be delayed in old rats compared with young females. This delay may correspond to the delayed onset, slow and low magnitude of plasma LH increase in old females. the ME-LHRH levels were generally higher in old rats than in young rats. Nevertheless, we found that the increase in plasma LH in response to progesterone treatment in estrogen-primed ovariectomized females was smaller in old rats than young rats. These results suggest that the LHRH secretory mechanism changes with age in female rats. Such alterations may result in the accumulation of LHRH in the mid-hypothalamic area and an increase in ME-LHRH.
| Original language | English |
|---|---|
| Pages (from-to) | 213-221 |
| Number of pages | 9 |
| Journal | Endocrinologia Japonica |
| Volume | 37 |
| Issue number | 2 |
| DOIs | |
| Publication status | Published - Jan 1 1990 |
| Externally published | Yes |
Fingerprint
ASJC Scopus subject areas
- Endocrinology
- Engineering(all)
Cite this
Hypothalamic luteinizing hormone-releasing hormone (LHRH) and LH secretion in aging female rats. / Takahashi, S.; Nomura, K.; Kawashima, S.
In: Endocrinologia Japonica, Vol. 37, No. 2, 01.01.1990, p. 213-221.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Hypothalamic luteinizing hormone-releasing hormone (LHRH) and LH secretion in aging female rats
AU - Takahashi, S.
AU - Nomura, K.
AU - Kawashima, S.
PY - 1990/1/1
Y1 - 1990/1/1
N2 - Age-related changes in hypothalamic luteinizing hormone-releasing hormone (LHRH) and luteinizing hormone (LH) secretion were studied in young (6 months), middle-aged (12 months) and old (18 months) female rats. The LHRH levels in the mid-hypothalamic area were higher in intact middle-aged and old females than in young ones. Additionally, there was no age difference in the hypothalamic LHRH levels in male rats. In order to clarify the significance of this age-related increase in female rats, we examined the effects of progesterone treatment in estrogen-primed ovariectomized young and old rats on the LHRH levels in the median eminence (ME) and on plasma LH levels. We found phasic changes in ME-LHRH and plasma LH levels in estrogen-primed rats following progesterone treatment in rats of both ages, but the progesterone-induced change in ME-LHRH levels tended to be delayed in old rats compared with young females. This delay may correspond to the delayed onset, slow and low magnitude of plasma LH increase in old females. the ME-LHRH levels were generally higher in old rats than in young rats. Nevertheless, we found that the increase in plasma LH in response to progesterone treatment in estrogen-primed ovariectomized females was smaller in old rats than young rats. These results suggest that the LHRH secretory mechanism changes with age in female rats. Such alterations may result in the accumulation of LHRH in the mid-hypothalamic area and an increase in ME-LHRH.
AB - Age-related changes in hypothalamic luteinizing hormone-releasing hormone (LHRH) and luteinizing hormone (LH) secretion were studied in young (6 months), middle-aged (12 months) and old (18 months) female rats. The LHRH levels in the mid-hypothalamic area were higher in intact middle-aged and old females than in young ones. Additionally, there was no age difference in the hypothalamic LHRH levels in male rats. In order to clarify the significance of this age-related increase in female rats, we examined the effects of progesterone treatment in estrogen-primed ovariectomized young and old rats on the LHRH levels in the median eminence (ME) and on plasma LH levels. We found phasic changes in ME-LHRH and plasma LH levels in estrogen-primed rats following progesterone treatment in rats of both ages, but the progesterone-induced change in ME-LHRH levels tended to be delayed in old rats compared with young females. This delay may correspond to the delayed onset, slow and low magnitude of plasma LH increase in old females. the ME-LHRH levels were generally higher in old rats than in young rats. Nevertheless, we found that the increase in plasma LH in response to progesterone treatment in estrogen-primed ovariectomized females was smaller in old rats than young rats. These results suggest that the LHRH secretory mechanism changes with age in female rats. Such alterations may result in the accumulation of LHRH in the mid-hypothalamic area and an increase in ME-LHRH.
UR - http://www.scopus.com/inward/record.url?scp=0025179413&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0025179413&partnerID=8YFLogxK
U2 - 10.1507/endocrj1954.37.213
DO - 10.1507/endocrj1954.37.213
M3 - Article
C2 - 2226340
AN - SCOPUS:0025179413
VL - 37
SP - 213
EP - 221
JO - Endocrine Journal
JF - Endocrine Journal
SN - 0918-8959
IS - 2
ER -